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December 11, 2013 Saleh Group has co-authored a journal article in Environmental Science and Technology .

Saleh Group has co-authored a journal article in Environmental Science and Technology titled: "Effects of Chloride and Ionic Strength on Physical Morphology, Dissolution, and Bacterial Toxicity of Silver Nanoparticles". ARM Nabiul Afrooz and Nirupam Aich also co-authored this paper. This work is a result of successful collaboration with Dr. Mary J Kirisits' group at UT Austin. The article studies role of chloride at controlled ionic strength conditions on toxicity of silver nanoparticles (AgNPs). The paper elucidates mechanisms of toxicity using aggregation state, fractal dimension, morphology, and dissolution properties of AgNPs.

Abstract: In this study, we comprehensively evaluate chloride- and ionic-strength-mediated changes in the physical morphology, dissolution, and bacterial toxicity of silver nanoparticles (AgNPs), which are one of the most-used nanomaterials. The findings isolate the impact of ionic strength from that of chloride concentration. As ionic strength increases, AgNP aggregation likewise increases (such that the hydrodynamic radius [HR] increases), fractal dimension (Df) strongly decreases (providing increased available surface relative to suspensions with higher Df), and the release of Ag(aq) increases. With increased Ag+ in solution, Escherichia coli demonstrates reduced tolerance to AgNP exposure (i.e., toxicity increases) under higher ionic strength conditions. As chloride concentration increases, aggregates are formed (HR increases) but are dominated by AgCl0(s) bridging of AgNPs; relatedly, Df increases. Furthermore, AgNP dissolution strongly increases under increased chloride conditions, but the dominant, theoretical, equilibrium aqueous silver species shift to negatively charged AgClx(x-1)- species, which appear to be less toxic to E. coli. Thus, E. coli demonstrates increased tolerance to AgNP exposure under higher chloride conditions (i.e., toxicity decreases). Expression measurements of katE, a gene involved in catalase production to alleviate oxidative stress, support oxidative stress in E. coli as a result of Ag+ exposure. Overall, our work indicates that the environmental impacts of AgNPs must be evaluated under relevant water chemistry conditions.


August 22, 2013 A workshop on problem-based learning for nanotechnology has successfully been arranged by Drs. Saleh, Caicedo, and Pierce at USC.

A workshop on problem-based learning for nanotechnology has successfully been arranged by Drs. Saleh, Caicedo, and Pierce at USC. Eminent scholars in the fields of nanotechnology, society and technology, and education attended the workshop. The workshop is an outcome of the NSF grant, funded by Dr. Mary Poats' NUE program. This workshop had been extremely exciting and resulted in stimulating discussions at the interface of nanotechnology and society. Saleh Lab sincerely thanks the participants and expects to continue to contribute in the field of nano-education with the support of Drs. Caicedo and Pierce and the respected participants.






August 14, 2013 Saleh Group has published a journal article in Nanotechnology.

Saleh Group has published a journal article in Nanotechnology titled: "Preparation of Non-Aggregating Aqueous Fullerenes in Highly Saline Solutions with A Biocompatible Non-Ionic Polymer". Nirupam Aich, fourth year PhD student is the lead author in this paper. The article prepares non-aggregating nC60s and nC70s using a bio-compatible polymeric coating.

Abstract: Size-tunable stable aqueous fullerenes were prepared with different concentrations of biocompatible block-copolymer pluronic (PA) F-127, ranging from 0.001% to 1% (w/v). Size uniformity increased with the increase in PA concentration, yielding optimum 58.8+/-5.6 and 61.8+/-5.6 nm nC60s and nC70s, respectively (0.10 %w/v PA), as observed using dynamic light scattering technique. Fullerene aqueous suspensions also manifested enhanced stability in saline solution, Dulbecco's Modified Eagle Medium (DMEM), and Roswell Park Memorial Institute (RPMI) culture medium. Transmission electron microscopy was performed to elaborate on the morphology and size specificity of fullerene clusters. Physicochemical characterizations of the suspended fullerenes were performed through UV-Vis spectroscopy and electrophoretic mobility measurements. PA molecules showed size restriction by encasement, as observed via molecular dynamic simulation. Such solubilization with controllable size and non-aggregating behavior can facilitate application-enhancement and mechanistic environmental and toxicological studies of size-specific fullerenes.


August 5, 2013 Saleh Lab has been awarded a grant by National Science Foundation (NSF).

Saleh Lab has been awarded a grant by Nano Environmental Health and Safety Program at the National Science Foundation (NSF). The project is titled: "Collaborative Research: Fate, Transport, and Organismal Uptake of Rod-Shaped Nanomaterials". It is a three-way collaborative effort between Dr. Saleh, Dr. Vikesland of Virginia Tech, and Dr. Murphy of University of Illinois-Urbana Champaign. The Saleh Lab will evaluate the role of aspect ratio on aggregation and deposition behavior of nanomaterials.



July 11, 2013 Saleh Group has published a journal article in Chemosphere.

Saleh Group has published a journal article in Chemosphere titled: "Fractal Structures of Single-Walled Carbon Nanotubes in Biologically Relevant Conditions: Role of Chirality vs. Media Conditions". Recently graduated PhD student, Iftheker A Khan is the lead author in this paper. The article evaluates fractal dimension of single-walled carbon nanotubes in biological media conditions and studies the role of chirality on fractal structure formation.

Abstract: Aggregate structure of covalently functionalized chiral specific semiconducting single-walled carbon nanotubes (SWNTs) was systematically studied employing static light scattering (SLS). Fractal dimensions (Df) of two specific chirality SWNTs- SG65 and SG76 SWNTs with (6, 5) and (7, 6) chiral enrichments - were measured under four biological exposure media conditions, namely: Dulbecco's modified eagle medium (DMEM), minimum essential medium (MEM), Roswell Park Memorial Institute (RPMI) 1640 medium, and 0.9% saline solution. The SWNTs exhibited chiral dependence on Df with SG65 showing more fractal or loosely bound aggregate structures, i.e., lower Df values (range of 2.24+/-0.03 to 2.64+/-0.05), compared to the SG76 sample (range of 2.58+/-0.13 to 2.90+/-0.08). All the Df values reported are highly reproducible, measured from multiple SLS runs and estimated with 'random block-effects' statistical analysis that yielded all p values to be <0.001. The key mechanism for such difference in Df between the SWNT samples was identified as the difference in van der Waals (VDW) interaction energies of these samples, where higher VDW of SG76 resulted in tighter packing density. Effect of medium type showed lower sensitivity; however, presence of di-valent cations (Ca2+) in DMEM and MEM media resulted in relatively loose or more fractal aggregates. Moreover, presence of fetal bovine serum (FBS) and bovine serum albumin (BSA), used to mimic the in-vitro cell culture condition, reduced the Df values, i.e., created more fractal structures. Steric hindrance to aggregation was identified as the key mechanism for creating the fractal structures. Also, increase in FBS concentration from 1% to 10% resulted in increasingly lower Df values.

Full Paper


June 28, 2013 Saleh Group has published a journal article in Environmental Science and Technology.

Saleh Group has published a journal article in Environmental Science and Technology titled: "Single-Walled Carbon Nanotube Transport in Representative Municipal Solid Waste Landfill Conditions". Recently graduated PhD student, Iftheker A Khan is the lead author in this paper. The article studies transport of single-walled carbon nanotubes in complex landfill conditions. This study is a result of a successful collaboration of the Saleh Lab with Dr. Berge's municipal solid waste research.

Abstract: Single-walled carbon nanotubes (SWNTs) are being used in many consumer products and devices. It is likely that as some of these products reach the end of their useful life, they will be discarded in municipal solid waste landfills. However, there has been little work evaluating the fate of nanomaterials in solid waste environments. The purpose of this study is to systematically evaluate the influence of organic matter type and concentration in landfill-relevant conditions on SWNT transport through a packed-bed of mixed municipal solid waste (MSW) collectors. The influence of individual waste materials on SWNT deposition is also evaluated. Transport experiments were conducted through saturated waste-containing columns over a range of simulated leachate conditions representing both mature and young leachates. Results indicate that SWNT transport may be significant in mature waste environments, with mobility decreasing with decreasing humic acid concentration. SWNT mobility in the presence of acetic acid was inhibited, suggesting their mobility in young waste environments may be small. SWNTs also exhibited collector media-dependent transport, with greatest transport in glass and least in paper. These results represent the first study evaluating how leachate age and changes in waste composition influence potential SWNT mobility in landfills.

Full Paper


June 3, 2013 Saleh Group has published an article on nanotechnology education in the Journal of Nano Education.

Saleh Group has published an article on nanotechnology education in the Journal of Nano Education. The title of the article is: "Nano in a Global Context: Modular Course Design with Integrated Ethics Improves Core Knowledge in Nanotechnology". Dr. Saleh is the lead author in this article. USC's Drs. Juan Caicedo (Civil and Environmental Engineering) and Ann Johnson (History and Philosophy) are the other lead authors in this article. This article is the first in a series of education based papers that resulted from Saleh Group's NSF grant on nanotechnology edcaution

Abstract: A problem-based learning (PBL) course was designed to teach the principles and application of nanotechnology through a real-world problem of global significance: water decontamination. The novel course design also attempted a close integration of social and ethical component of nanotechnology through a weekly lecture on these aspects, in parallel to the technical component. Overall the course pursued three principal goals: introduce nanotechnology to engineering students who otherwise have no formal exposure to this emerging technology; integrate the approaches pertaining to nanotechnology offered by different engineering disciplines; and fully incorporate discussions about the practical ethical implications of implementing nano in a real, developing world context. In this endeavor, the course structure was based on introductory modules discussing fundamental principles of nanotechnology as well as key issues related to water contamination in developing countries. Four inquiry-based modules followed the introductory segment engaged students in learning nanotechnology principles to solve water contamination issues, namely: arsenic removal, virus detection, mechanical sensing, and detection of arsenic. Assessment conducted via pre- and post-tests and a survey using a nanotechnology concept inventory show substantial gain in core knowledge. It is believed that the PBL based course design alongside with the integrated social and ethical component encouraged the students to learn and apply the principles of nanotechnology toward a real-life social problem. The ethical perspective has likely reinforced the purpose of learning and thus has resulted in an enhanced learning experience.



May 17, 2013 Saleh Group has co-authored an article published in Il Nuovo Cimento C, a journal published by Italian Physical Society.

Saleh Group has co-authored an article published in Il Nuovo Cimento C, a journal published by Italian Physical Society. The title of the paper is: "Nanoparticle dynamics in the presence and absence of a cellular uptake altering chemical". Fourth year PhD student, A. R. M. Nabiul Afrooz is a co-author in this paper. The article is a result of the collaboration between the Saleh Lab and Dr. Saber Hussain of AFRL.

Abstract: The far-reaching applications of nanoparticles (NPs) in drug delivery, medical imaging, diagnostics, and therapeutics have led to an increased potential for interfacing with a diverse range of biological environments. While metallic NPs such as copper NPs have been explored for their antimicrobial and catalytic properties, they have been shown to induce undesirable toxic effects. Nonetheless, biomodulators may be employed to control this cytotoxicity. Dynasore is a dynamin GTPase inhibitor that has been shown to rapidly and reversibly block clathrindependent endocytic traffic within minutes of application. Here, we demonstrate that Dynasore can chemically bio-modulate the toxic effects of copper nanoparticles (Cu NPs), but not through reducing Cu NP internalization. In fact, Dynasore seems to possess secondary effects that have been unreported to date. We propose and test three potential mechanisms of cytotoxicity modulation: 1) through changes in agglomeration pattern, 2) through potential quenching of reactive oxygen species (ROS), and 3) through Cu+2 ion chelation. These results have far-reaching implications for understanding the complex interactions that occur at the interface of NPs in biological environments, especially during mechanistic chemical modification strategies.


Full Paper


April 29, 2013 Dr. Saleh has officially accepted a faculty position at the department of Civil, Architectural and Environmental Engineering (CAEE), Cockrell School of Engineering, University of Texas at Austin. .

Dr. Saleh has officially accepted a faculty position at the department of Civil, Architectural and Environmental Engineering (CAEE), Cockrell School of Engineering, University of Texas at Austin. He will join there in January 2014. Saleh Lab will continue the ongoing research at USC and ensure a seamless transition to UT Austin. We thank the support of all the funding agencies (NSF, NIH, USAF, SCDOT, GSE&C), and collaborators for enabling to establish a successful research program.



April 09, 2013 Nirupam Aich, a 4th year PhD student in the Saleh Group, has been awarded the Support to Promote Research and Creativity (SPARC) Graduate Research Fellowship.

Nirupam Aich, a 4th year PhD student in the Saleh Group, has been awarded the Support to Promote Research and Creativity (SPARC) Graduate Research Fellowship. He is one of the first recipients of this fellowship and the only environmental engineering graduate student awardee, to receive this prestigious fellowship awarded by the Office of the Vice President for Research. The $5000 SPARC fellowship, which rewards excellence in graduate student grant writing and creativity in research, will benefit Nirupam's dissertation and other academic activities.



March 03, 2013 Saleh Group has published a journal article in Journal of Intelligent Material Systems and Structures titled: "Triboluminescence for Distributed Damage Assessmentin Cement Based Materials".

Saleh Group has published a journal article in Journal of Intelligent Material Systems and Structures titled: "Triboluminescence for Distributed Damage Assessmentin Cement Based Materials". Third year PhD student, NirupamAich is the lead author in this paper. The article presents a simple and novel method to detect crack on cementitious matrices using a triboluminescent material.

Abstract: Triboluminescent (TL) materials are promising in the field of Structural Health Monitoring (SHM) for real time crack detection and related damage assessment. This study presents a simple, however novel, image processing protocol to detect and quantify luminescence from crack-formation in cement based matrices. 2" × 2" (5.1 cm x 5.1 cm)mortar cubes were loaded in compression with an external coating of manganese doped zinc sulfide (ZnS:Mn) TL material. The concentration of TL material and rate of loading were varied to evaluate luminescence response. A DSLR camera was employed to capture luminescence from the resulting cracks which formed and propagated during failure. The images were then analyzed with an image processor and total luminescence/pixel along the cracks was quantified. Results show that overall luminescence increase with the increase in TL concentration as well as with the rate of loading. This article presents a novel method that can be applied to monitor crack formation in cement based materials, providing reliable accuracy in luminescence quantification.



February 21, 2013 Dr Saleh's poster titled "Mechanistic hetero-aggregation of gold nanoparticles for a Wide Range of Solution chemistries" has been awarded Honorable Mention at the 1st Sustainable Nanotechnology Conference, Arlington, VA.

Dr Saleh's poster titled "Mechanistic hetero-aggregation of gold nanoparticles for a Wide Range of Solution chemistries" has been awarded Honorable Mention at the 1st Sustainable Nanotechnology Conference, Arlington, VA. The award was announced on Nov 6, 2012 and has recently been listed in Sustainable Nanotechnology's February newsletter. This poster presented the results of a recently published paper in ES&T. Please refer to the published article here.



January 28, 2013 Saleh Group has published a journal article in Environmental Science and Technology titled: "Mechanistic Hetero-aggregation of Gold Nanoparticles in a Wide Range of Solution Chemistry".

Saleh Group has published a journal article in Environmental Science and Technology titled: "Mechanistic Hetero-aggregation of Gold Nanoparticles in a Wide Range of Solution Chemistry". Third year PhD student, ARM Nabiul Afrooz is the lead author in this paper. The article studies aggregation of gold nanospheres in presence of non-ionic polymeric surfactant coated single-walled carbon nanotubes in a wide range of solution chemistry.

Abstract:

Hetero-aggregation behavior of gold nanospheres (AuNS) in presence of pluronic acid (PA) modified single-walled carbon nanotubes (PA-SWNTs), was systematically studied for a wide range of mono- and di-valent (NaCl and CaCl2) electrolyte conditions. Homo-aggregation rates of AuNS were also determined to delineate hetero-aggregation mechanisms. Time resolved dynamic light scattering (DLS) was employed to monitor aggregation. The homo-aggregation of AuNS showed classical Derjaguin-Landau-Verwey-Overbeek (DLVO) type behavior with defined reaction limited (RLCA) and diffusion limited (DLCA) aggregation regimes. PA-SWNTs homo-aggregation on the other hand showed no response with electrolyte increase. AuNS hetero-aggregation rates on the other hand, showed regime dependent response. At low electrolyte or RLCA regime, AuNS hetero-aggregation showed significantly slower rates, compared to its homo-aggregation behavior; while, enhanced hetero-aggregation was observed for DLCA regime. The key mechanisms of hetero-aggregation of AuNS are identified as 'obstruction to collision' at RLCA regime and 'facilitating enhanced attachment' at DLCA regime, manifested by the presence of PA-SWNTs. Presence of Suwannee River humic acid (SRHA) also showed aggregation enhancement for both homo- and hetero-systems, in presence of divalent Ca2+ ions. Bridging between SRHA molecules is identified as the key mechanism for increased aggregation rate. The findings of this study are relevant, particularly to co-existence of engineered nanomaterials. The strategy of using non-aggregating PA-SWNTs is a novel experimental strategy that can be adopted elsewhere to further the hetero-aggregation studies for a wider set of particles and surface coatings.



January 23, 2013 Nabiul Afrooz awarded the prestigious American Chemical Society (ACS) Environmental Chemistry Graduate Student Award 2013.

ARM Nabiul Afrooz, a 3rd year PhD student in the Saleh Group has been awarded the prestigious American Chemical Society (ACS) Environmental Chemistry Graduate Student Award 2013. Nabiul competed nationally with the top environmental engineering graduate students to win this award. Award was based upon students' records in course work, evidence of research productivity and recommendations from graduate faculty advisor. Primary emphasis is given to Nabiul's potential for future contributions as professionals in environmental chemistry. Nabiul will receive a check from ACS Environmental Chemistry Division and his Institution's, and advisor's names will be posted on the ACS website for one full year. Congratulations Nabiul!


January 23, 2013 Saleh Group has published a journal article in Environmental Science and Technology titled: "Chirality Affects Aggregation Kinetics of Single-Walled Carbon Nanotubes".

Saleh Group has published a journal article in Environmental Science and Technology titled: "Chirality Affects Aggregation Kinetics of Single-Walled Carbon Nanotubes". Recently graduated PhD student, Iftheker A Khan is the lead author in this paper. The article studies the role of chirality on aggregation of single-walled carbon nanotubes.

Abstract:

Aggregation kinetics of chiral-specific semiconducting single-walled carbon nanotubes (SWNTs) were systematically studied through time-resolved dynamic light scattering. Varied monovalent (NaCl) and divalent (CaCl2) electrolyte composition was used as background solution chemistry. Suwannee River humic acid (SRHA) was used to study the effects of natural organic matter on chirally separated SWNT aggregation. Increasing salt concentration and introduction of divalent cations caused aggregation of SWNT clusters by suppressing the electrostatic repulsive interaction from the oxidized surfaces. The (6,5) SWNTs, i.e., SG65, with relatively lower diameter tubes compared to (7,6), i.e., SG76, showed substantially higher stability (7 and 5 folds for NaCl and CaCl2, respectively). The critical coagulation concentration (CCC) values were 96 and 13 mM NaCl in case of NaCl and 2.8 and 0.6 mM CaCl2 for SG65 and SG76, respectively. The increased tube diameter for (7,6) armchair SWNTs likely presented with higher van der Waals interaction and thus increased the aggregation propensity substantially. The presence of SRHA enhanced SWNT stability in divalent CaCl2 environment through steric interaction from adsorbed humic molecules; however showed little or no effects for monovalent NaCl. The mechanism of aggregation-describing favorable interaction tendencies for (7,6) SWNTs-is probed through ab initio molecular modeling. The results suggest that SWNT stability can be chirality dependent in typical aquatic environment.



December 7, 2012 A R M Nabiul Afrooz awarded Bert Storey Fellowship

A R M Nabiul Afrooz, a third year PhD student in the Saleh Group has been awarded the Bert Storey Fellowship, 2012-2013. This fellowship is awarded by Civil and Engineering Department of the College of Engineering and Computing in USC to the top civil and environmental graduate student. The fellowship is named after Mr. Bert Storey, a long time patron of the University. Nabiul will receive an honorarium to support his research activities. Congratulations Nabiul!


November 23, 2012 Saleh Group has co-authored a journal article published in J Mater Chem B.

Saleh Group has co-authored a journal article published in J Mater Chem B titled: "A novel core-shell microcapsule for encapsulation and 3D culture of embryonic stem cells". This work is a result of a collaborative work with Dr. Xiaoming He of Ohio State University.

Abstract:

In this study, we report the preparation of a novel microcapsule of 100 ?m with a liquid (as compared to a solid-like alginate hydrogel) core and an alginate-chitosan-alginate (ACA) shell for encapsulation and culture of embryonic stem (ES) cells in the miniaturized 3D space of the liquid core. Murine R1 ES cells cultured in the microcapsules were found to survive (>90%) well and proliferate to form either a single aggregate of pluripotent cells or an embryoid body (EB) of more differentiated cells in each microcapsule within 7 days, depending on the culture medium used. This novel microcapsule technology allows massive production of the cell aggregates or EBs of uniform size and controllable pluripotency, which is important for the practical application of stem cell based therapy. Moreover, the semipermeable ACA shell was found to significantly reduce immunoglobulin G (IgG) binding to the encapsulated cells by up to 8.2 times, compared to non-encapsulated cardiac fibroblasts, mesenchymal stem cells, and ES cells. This reduction should minimize inflammatory and immune responses induced damage to the cells implanted in vivo because IgG binding is an important first step of the undesired host responses. Therefore, the ACA microcapsule with selective shell permeability should be of importance to advance the emerging cell-based medicine.


Full Paper


November 19, 2012 Saleh Group has published a journal article in Chemosphere.

Saleh Group has published a journal article in Chemosphere titled: "Spheres vs. Rods: The Shape of Gold Nanoparticles Influences Aggregation and Deposition Behavior". 3rd year graduate student A R M Nabiul Afrooz is the lead author in this paper. The article presents a fundamental study of shape-dependent aggregation and deposition of nano-scale gold in environmentally relevant systems. This article is the first in the series of articles resulting from a successful collaborative with Dr. Catherine Murphy at UIUC and Dr. Saber Hussain at USAF.

Abstract:

The influence of shape on nanomaterial aggregation and deposition was systematically studied with poly-acrylic acid (PAA) coated uniform-sized gold nanospheres (AuNSs) and nanorods (AuNRs). Time resolved dynamic light scattering was employed to study their aggregation kinetics in a wide range of mono- and di-valent electrolyte conditions. Results indicated that PAA coated AuNSs have higher aggregation propensity compared to anisotropic PAA coated AuNRs, as observed through critical coagulation concentration (CCC). The CCC values were estimated as 50 mM NaCl and 1.8 mM CaCl2 for AuNS, which showed substantial increase to 250 mM NaCl and 7 mM CaCl2 for anisotropic AuNRs. Though electrokinetic behavior showed similar surface potential for the spherical and rod-shaped materials, the geometric differences between the samples have likely resulted in unique conformation of the PAA coatings, leading to different magnitudes of steric hindrances and hence yielding the observed aggregation behavior. The deposition kinetics was monitored using the quartz crystal microbalance with dissipation technique. AuNRs showed relatively slower deposition compared to AuNSs for low electrolytes concentrations. With the increase in electrolyte concentration, the differences in deposition rates between spheres and rods diminished. The results from this study showed that the shape of nanomaterials can influence interfacial properties and result in unique aggregation and deposition behavior under typical aquatic conditions.


Full Paper


November 13, 2012 Nirupam has successfully defended his MS thesis.

Nirupam Aich has successfully defended his MS thesis titled: "Method Development for Transmission Electron Microscopy of Carbon Nanotubes and for Distributed Sensing with Triboluminescent Materials in The Premise of Sustainable Infrastructure". Both the papers presented in this thesis have already been accetpted for publication. Congratulations Nirupam! Nirupam is continuing at USC as a PhD student.


October 04, 2012 Dr. Saleh has held an outreach effort at the Dutch Fork High School, Irmo, SC.

Dr. Saleh has held an outreach effort at the Dutch Fork High School, Irmo, SC. The outreach involved a seminar on nanotechnology, followed by an activity on 'surface area to volume ratio' using fullerene models. Dr. Saleh extended this outreach through Dutch Fork High School's Physical Sciences Honors course (Course No.: 3211STHW) with 48 freshmen. This activity will be repeated at the end of this month. A more extensive outreach effort involving a three class series with lectures, hands on activities, and EM via Skype program will be executed over Spring 2013.


September 28, 2012 Society of Toxicology (SOT) has inducted Dr. Saleh as a full member.

Society of Toxicology (SOT) has inducted Dr. Saleh as a full member. Dr. Saleh is honored with the induction and will be deeply involved in the SOT activities. The first of such activities is a professional course offering by Dr Saleh titled: 'Aggregation Behavior of Nanomaterials Under Biological Exposure Conditions' at the 52nd SOT Annual Meeting from March 10-14, 2013 at San Antonio, TX.


September 24, 2012 Saleh Group has published a journal article in J Res Updates in Poly Sci titled: "Applied TEM Approach for Micro/Nanostructural Characterization of Carbon Nanotube Reinforced Cementitious Composites".

Saleh Group has published a journal article in J Res Updates in Poly Sci titled: "Applied TEM Approach for Micro/Nanostructural Characterization of Carbon Nanotube Reinforced Cementitious Composites". 3rd year graduate student Nirupam Aich is the lead author in this paper. The article presents a novel approach to perform electron microscopy on complex cementitious composite matrices to characterize carbonaceous nanomaterial and cement matrix compatibility. This article is the first in the series of articles in the making on Saleh Group's collaborative effort with Drs. Ziehl and Matta at USC.


August 30, 2012 Saleh Lab has received an R01 funding from the National Institute of Health (NIH).

Saleh Lab has received an R01 funding from the National Institute of Health (NIH). The project titled: "Contribution of Toll-like Receptors in the Pulmonary Response to Nanoparticles and Pathogens" is a collaborative effort with Dr. Tara Sabo-Attwood at the University of Florida. The Saleh Lab will evaluate nanotube-virus interfacial interaction to study the mechanisms of immune signals of lung epithelial cells triggered by the pathogenic and particulate entities.


August 23, 2012Dr. Iftheker A Khan has successfully defended his doctoral dissertation work titled: "Aggregation Behavior of Chiral Single-Walled Carbon Nanotubes and Their Transport in Landfill Conditions".

Dr. Iftheker A Khan has successfully defended his doctoral dissertation work titled: "Aggregation Behavior of Chiral Single-Walled Carbon Nanotubes and Their Transport in Landfill Conditions". Dr. Khan has already published 5 journal articles with 4 more under review. His achievements has earned him a post-doctoral position at the National Center for Toxicological Research (NCTR) at Little Rock, AR. Congratulations Dr. Khan!

NCTR

May 01, 2012 Iftheker A Khan Chosen as USC Graduate School Summer Dissertation Fellow

Iftheker A khan, a final year PhD student in the Saleh Group has been chosen as the 2012 USC Graduate School Summer Dissertation Fellow. This fellowship is awarded by the University of South Carolina Graduate School and only four students in the entire university is bestowed with such an honor. Iftheker's excellent academic record and exemplary research performance has earned him this honor. As part of this fellowship, Iftheker will receive a $2,500 financial award toward his graduation and dissertation completion. Congratulations Iftheker!


April 20, 2012 Samuel P. Rollings won the 1st prize in Discovery Day

Samuel P. Rollings, a senior at USC and a Magellan Scholar working in Saleh Lab has won the 1st prize at Discovery Day. The title of his poster was "Modular Nano-enabled Sorption Cartridge for Water Treatment". This work is focused on developing a simply yet novel technique to coat filter surfaces with advanced nanomaterials. Congratulations Sam!


April 13, 2012 Saleh Group has published a journal article in Applied Biochemistry and Biotechnology titled, "Effect of Gold Nanosphere Surface Chemistry on Protein Adsorption and Cell Uptake in Vitro".

Saleh Group has published a journal article in Applied Biochemistry and Biotechnology titled, "Effect of Gold Nanosphere Surface Chemistry on Protein Adsorption and Cell Uptake in Vitro". 3rd year graduate student ARM Nabiul Afrooz and Dr. Saleh are co-authors in this paper with the nanotoxicology research group at Wright Patterson Air Force Base.


Abstract:

Gold nanoparticles exhibit unique spectral properties that make them ideal for biosensing, imaging, drug delivery, and other therapeutic applications. Interaction of gold nanoparticles within biological environments is dependent on surface characteristics, which may rely on particular capping agents. In this study, gold nanospheres (GNS) synthesized with different capping agents-specifically citric acid (CA) and tannic acid (TA)- were compared for serum protein adsorption and cellular uptake into a lung epithelial cell-line (A549). Both GNS samples exhibited noticeable protein adsorption based on surface charge data after exposure to serum proteins. Light scattering measurements revealed that GNS-CA-protein composites were smaller and less dense compared to GNS-TA-protein composites. The cell uptake characteristics of these NPs were also different. GNS-CA formed large clusters and elicited high uptake, while GNS-TA were taken up as discrete particles, possibly through non-endosomal mechanisms. These results indicate that the capping agents used for GNS synthesis result in unique biological interactions.


April 6, 2012 Saleh Group has recently received a competitive internal grant from the USC's VP of Research, Dr. Nagarkatii's office, under ASPIRE-I program.

Saleh Group has recently received a competitive internal grant from the USC's VP of Research, Dr. Nagarkatii's office, under ASPIRE-I program. The title of the proposals is: "Heteroaggregation and deposition of chirally separated single-walled carbon nanotubes in heterogeneous aquatic systems". This project will deal with development of novel techniques for analyzing fate and transport of nanomaterials in complex natural systems.


March 29, 2012 A journal article in the Journal of Nanoscience and Nanotechnology has been accepted where Dr. Saleh and iftheker Khan are co-authors.

A journal article entitled "Ultrasonication Study for Suspending Single-Walled Carbon Nanotubes in Water" has recently been accepted for publication in the Journal of Nanoscience and Nanotechnology where Dr. Saleh and Iftheker Khan are co-authors. This paper focuses on development of ultrasonication based standardized protocol for single walled carbon nanotube dispersion. .

Abstract:

A systematic calorimetry-based technique was developed to standardize single-walled carbon nanotube (SWNT) dispersion protocol. Simple calorimetric experiments were performed to benchmark the performance of the ultra-dismembrator. Temperature profiles for the sonication period were utilized to estimate energy input to the system. Energy loss profile was generated for the ultra-dismembrator in use and a calibration relationship was formulated that could standardize the sonication process. The standardized protocol was used to prepare aqueous SWNT suspensions-sonicating SWNTs in a varied range of input energy (18-100 kJ) in water. SWNT mass fractions suspended for each energy input was accurately measured and the suspended SWNT samples were characterized for morphology, surface potential, cluster size and structure, and chemical functionality using high resolution transmission electron microscopy (HRTEM), electrophoresis, dynamic and static light scattering (DLS/SLS), and Raman spectroscopy. The study demonstrated that suspended mass of SWNTs increased up to 18 kJ of energy input with no further increase upon continued energy input. The physicochemical properties showed similar trend for energy input. The aggregate cluster size, surface potential behavior, as well as the Raman defect properties plateaued after the initial energy input. The significant changes observed were limited to morphological properties, i.e., shorter length, debundled, and sharp edged SWNTs and fractal cluster formation (lower Df) with increased input energy.


March 28, 2012 Iftheker Khan, a fourth year PhD student in Saleh Group has received 2nd prize in poster presentation on the Graduate Student Day 2012 at the University of South Carolina.

Iftheker Khan, a fourth year PhD student in Saleh Group has received 2nd prize in poster presentation on the Graduate Student Day 2012 at the University of South Carolina. The topic of his poster was 'Fractal Structures of Single-Walled Carbon Nanotubes in Environmental and Biologically Relevant Conditions: Role of Chirality.' Congratulations Iftheker!


January 13, 2012 A journal article in Langmuir has been published where Dr. Saleh and A R M Nabiul Afrooz are co-authors.

A journal article entitled "Does Shape Matter? Bioeffects of Gold Nanomaterials in a Human Skin Cell Model" has recently been published in Langmuir where Dr. Saleh and Nabiul Afrooz are co-authors. This paper focuses on the shape dependent cellular response to gold nanoparticles.

Abstract:

Gold nanomaterials (AuNMs) have distinctive electronic and optical properties, making them ideal candidates for biological, medical, and defense applications. Therefore, it is imperative to evaluate the potential biological impact of AuNMs before employing them in any application. This study investigates two AuNMs with different aspect ratios (AR) on mediation of biological responses in the human keratinocyte cell line (HaCaT) to model potential skin exposure to these AuNMs. The cellular responses were evaluated by cell viability, reactive oxygen species (ROS) generation, alteration in gene and protein expression, and inflammatory response. Gold nanospheres, nominally 20 nm in diameter and coated with mercaptopropane sulfonate (AuNS-MPS), formed agglomerates when dispersed in cell culture media, had a large fractal dimension (Df = 2.57+-0.4) (i.e., tightly bound and densely packed) and were found to be nontoxic even at the highest dose of 100 ?g/mL. Highly uniform, 16.7 nm diameter, and 43.8 nm long polyethylene glycol-capped gold nanorods (AuNR-PEG) also formed agglomerates when dispersed into the cell culture media. However, the agglomerates had a smaller fractal dimension (Df = 1.28+-0.08) (i.e., loosely bound) and were found to be cytotoxic to the HaCaT cells, with a significant decrease in cell viability occurring at 25 microgram/mL and higher. Moreover, AuNR-PEG caused significant ROS production and up-regulated several genes involved in cellular stress and toxicity. These results, combined with increased levels of inflammatory and apoptotic proteins, demonstrated that the AuNR-PEG induced apoptosis. Exposure to AuNS-MPS, however, did not show any of the detrimental effects observed from the AuNR-PEG. Therefore, we conclude that shape appears to play a key role in mediating the cellular response to AuNMs.


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December 06, 2011 A recent journal article from Saleh group titled "Preparation and Characterization of Stable Aqueous Higher Order Fullerenes" has been accepted in Nanotechnology.

A recent journal article from Saleh group titled "Preparation and Characterization of Stable Aqueous Higher Order Fullerenes" has been accepted in Nanotechnology. 2nd year graduate student Nirupam Aich is the lead author of this paper. The paper discussed aqueous solubilization of higher fullerenes and presents their interaction energies at molecular level and physicochemical properties. This paper has been highlighted by the journal as an 'article of particular interest'.
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December 5, 2011 Saleh Group has recently received the Magellan Scholar Program grant from the University of South Carolina titled "MGS Modular Nano-Enabled Sorption Cartridge Design for Water Treatment".

Saleh Group has recently received the Magellan Scholar Program grant from the University of South Carolina titled "MGS Modular Nano-Enabled Sorption Cartridge Design for Water Treatment". This grant will also help Sam Rollings, an undergraduate student from this group to perform innovative research as a prestigious Magellan scholar to remediate water pollution issues. Potential application of carbonaceous nanoparticles to perform in advanced water treatmet processes will be the focus of this research.


November 10, 2011 Saleh Group has recently received a US Air Force grant from the Wright Patterson Air Force Base. The grant will focus on mechanistic understanding of nano-toxicity of metallic nanoparticles.

Saleh Group has recently received a US Air Force (USAF) grant from the Wright Patterson Air Force Base titled, "Developing Predicting Capability for Nanoparticle Aggregation and Aggregate Structure Evolution in Biologically Relevant Systems". The project will focus on mechanistic understanding of nano-toxicity of metallic nanoparticles. This project is a result of a successful collaboration between Dr. Saleh and an eminent toxicologist and scientist Dr. Saber Hussain of USAF.


October 27, 2011 Nirupam Aich awarded Bert Storey Fellowship.

bert

Nirupam Aich, a second year PhD student in the Saleh Group has been awarded the M. Bert Storey Endowed Graduate Fellowship, 2011-2012. This fellowship is awarded by Civil and Engineering Department of the College of Engineering and Computing in USC to the top Civil and Environmental graduate student. The fellowship is named after Mr. Bert Storey, a long time patron of the University. Nirupam will receive a $1,250 award as acknowledgement of his outstanding performance in study and research. Congratulations Nirupam! Iftheker A. Khan, another senior PhD student in the Saleh Group was awarded the same fellowship last year.

 


September 30, 2011 Saleh Group has published three journal papers in Toxicology and Applied Pharmacology, Reprod Toxicol and Water Res titled, "The effects of TiO2 and Ag nanoparticles on reproduction and development of Drosophila melanogaster and CD-1", "Investigating the effects of functionalized carbon nanotubes on reproduction and development in Drosophila melanogaster and CD-1 mice", and "Removal of bisphenol A and 17a-ethinyl estradiol from landfill leachate using single-walled carbon nanotubes", respectively.

Saleh Group has published three journal papers in Toxicology and Applied Pharmacology, Reprod Toxicol and Water Res titled, "The effects of TiO2 and Ag nanoparticles on reproduction and development of Drosophila melanogaster and CD-1", "Investigating the effects of functionalized carbon nanotubes on reproduction and development in Drosophila melanogaster and CD-1 mice", and "Removal of bisphenol A and 17a-ethinyl estradiol from landfill leachate using single-walled carbon nanotubes", respectively. 2nd year graduate student ARM Nabiul Afrooz, 3rd year graduate student Iftheker A Khan, and Dr. Saleh are co-authors in these papers. The toxicology papers are a result of successful collaboration between the Saleh Group at USC and the Walker Group of Queens University, Canada. The third paper is published as an outcome of Dr. Saleh's research work on SWNT membranes with Dr. Yoon of USC.



August 15, 2011 Dr. Saleh is co-organizing an Environmental Chemistry (ENVR) conference session at the 243rd ACS National Meeting-San Diego next March.

Dr. Saleh is co-organizing an Environmental Chemistry (ENVR) conference session at the 243rd ACS National Meeting-San Diego next March with Drs. John Fortner (University of Washington-St. Louis) and Saber Hussain (Wright Patterson Airforce Base and Wright State University). The title of session is "Nanomaterial Interaction on Biological Interfaces". All the organizers encourage authors to submit abstracts to this session. The abstract submission to PACS is now open thru October 17, 2011.


June 3, 2011 Saleh Group has presented two posters at the first Gordon Research Conference on Environmental Nanotechnology.

Saleh Group has presented two posters at the first Gordon Research Conference on Environmental Nanotechnology. The posters were titled as: "Aggregation Kinetics and Fractal Structures of Chirally Separated Single-Walled Carbon Nanotubes in Environmental and Biologically Relevant Systems" and "Removal of Micropollutants from Landfill Leachate, Seawater, and Brackish Water Using Single-Walled Carbon Nanotubes". These studies were funded by NSF and GSEC, respectively.



April 2, 2011 Saleh Group presented 5 technical papers in the 241st ACS National Meeting held at Anaheim, CA.

In the most recent ACS National Meeting held at Anaheim, CA from March 27-31, 2011, three members from Saleh Group, ARM Nabiul Afrooz, Nirupam Aich, and Iftheker A. Khan, presented five papers in the area of environmental fate, transport, and effects of engineered nanomaterials. These papers were presented in the environmental chemistry division that included topics of aggregation kinetics and aggregate structure studies of chiral single-walled carbon nanotubes (Khan et al.) aggregation behaviour of higher fullerenes and hybrid nanomaterials (Aich and Saleh), and aggregation kinetics of rod-like gold nanomaterials(Afrooz et al).


March 11, 2011 Dr. Saleh has recently presented an invited lecture at Wright Patterson Air Force Base (WPAFB), Dayton, OH.

Dr. Saleh has recently presented an invited lecture at Wright Patterson Air Force Base (WPAFB), Dayton, OH. Dr. Saleh's talk titled, "Aggregation and Surface Interaction of Carbonaceous and Metallic Nanomaterials: Environmental and Biologically Relevant Conditions". Saleh Lab has established a successful collaboration with WPAFB and will continue to work closely with the scientists there in nano-toxicological studies.



February 1, 2011 Iftheker A Khan, a 3rd year PhD student in the Saleh Group has been awarded the prestigious American Chemical Society (ACS) Environmental Chemistry Graduate Student Award 2011.

Iftheker A Khan, a 3rd year PhD student in the Saleh Group has been awarded the prestigious American Chemical Society (ACS) Environmental Chemistry Graduate Student Award 2011. Iftheker competed nationally with the top environmental engineering graduate students to win this award. Award was based upon students' records in course work, evidence of research productivity and recommendations from graduate faculty advisor. Primary emphasis is given to Iftheker's potential for future contributions as professionals in environmental chemistry. The number of applications from qualified recipients exceeded previous years, which makes this award for 2011 highly competitive. Iftheker will receive a check from ACS Environmental Chemistry Division and Iftheker's, his Institution's, and advisor’s names will be posted on the ACS website for one full year. Congratulations Iftheker!


January 28, 2011 Saleh Group has published a recent paper in J Haz Mat. titled, "Barrier properties of poly(vinyl alcohol) membranes containing carbon nanotubes or activated carbon".

Saleh Group has published a recent paper in J Haz Mat. titled, "Barrier properties of poly(vinyl alcohol) membranes containing carbon nanotubes or activated carbon". 3rd year graduate student Iftheker A Khan, former undergrad researcher Atif A Chowdhury, and Dr. Saleh are co-authors in this paper with University of Minnesota’s Bill Arnold. This paper focuses on improvement of PVA membrane properties through incorporation of carbon nanotubes for removal of dissolved tri-chlorobenzene and copper.

Abstract
Carbon nanotube addition has been shown to improve the mechanical properties of some polymers. Because of their unique adsorptive properties, carbon nanotubes may also improve the barrier performance of polymers used in contaminant containment. This study compares the barrier performance of poly(vinyl alcohol) (PVA) membranes containing single-walled carbon nanotubes (SWCNTs) to that for PVA containing powdered activated carbon (PAC). Raw and surface-functionalized versions of each sorbent were tested for their abilities to adsorb 1,2,4-trichlorobenzene and Cu2+, representing the important hydrophobic organic and heavy metal contaminant classes, as they diffused across the PVA. In both cases, PAC (for 1,2,4-trichlorobenzene) and functionalized PAC (for Cu2+) outperformed SWCNTs on a per mass basis by trapping more of the contaminants within the barrier membrane. Kinetics of sorption are important in evaluating barrier properties, and poor performance of SWCNT-containing membranes as 1,2,4-TCB barriers is attributed to kinetic limitations.


Full Paper


December 2, 2010 Iftheker A Khan awarded Bert Storey Fellowship.

Iftheker A khan, a second year PhD student in the Saleh Group has been awarded the M. Bert Storey Endowed Graduate Fellowship, 2010-2011. This fellowship is awarded by Civil and Engineering Department of the College of Engineering and Computing in USC to the top Civil and Environmental graduate student. The fellowship is named after Mr. Bert Storey, a long time patron of the University. Iftheker will receive a $1,250 award that will support his research activities. Congratulations Iftheker!




October 29, 2010 Dr. Saleh has been selected as the nano-environmental thrust leader of USC Nanocenter.

USC Nanocenter has selected Dr. Saleh as the nano-environmental thrust leader. He is the only untenured Assistant Professor among seven other distinguished Professors in this elite pack of leaders of nanotechnology thrusts. Dr. Saleh's primary role will be to frame USC's nano-environmental research focus in the coming years under the guidance of the Nanocenter Director Tom Vogt.


October 06, 2010 News coverage of NSF education grant in USC Nanocenter website.

USC Nanocenter has profiled Saleh Group's recent grant on nanoeducation in the amount of $200,000, funded by the EEC directorate of the National Science Foundation. The project is titled "NUE: Nano in a Global Context for Engineering Students". Read more on this grant in the Nanocenter website.


October 01, 2010 Saleh Group has been awarded an NSF grant from the EEC directorate amounting $200,000. Dr. Saleh is the PI   in the grant.

Saleh Group has received a grant on nanoeducation in the amount of $200,000, funded by the EEC directorate of the National Science Foundation. The project is titled "NUE: Nano in a Global Context for Engineering Students". Read more on this grant in the Civil and Environmental Engineering department website.


September 3, 2010 Dr. Saleh has been formally nominated as a key member of the Virginia Tech Center of Sustainable Nanotechnology (VTSuN).

Dr. Saleh has been selected as the only outside Virginia Tech faculty to take part in the multi-disciplinary sustainable nanotechnology effort of Virginia Tech Center of Sustainable Nanotechnology (VTSuN) center. The mission of VTSuN is to conduct and publicly disseminate research results concerning the development and evaluation of promising green nanomaterials, nanodevices, and nanotechnologies for their environmental sustainability and safety as well as the application of nanotechnology and nanoscience to environmental sustainability issues. Professor Saleh will be collaborating with the center to understand the environmental transport of nanomaterials in river systems, an area that has remained virtually unexplored. VTSuN's team i.e., Drs. Navid Saleh, Panos Diplas, Clint Dancey, and Michael Hochella, is preparing a number of proposals to be submitted to NSF, NIH, and other funding agencies.


August 26, 2010 Saleh Group presented 4 technical papers in the 240th ACS National Meeting held at Boston, MA.

In the most recent ACS National Meeting held at Boston, MA from August 22-26, 2010, three members from Saleh Group, ARM Nabiul Afrooz, Nirupam Aich, and Iftheker A. Khan, presented four papers in the area of environmental fate, transport, and effects of engineered nanomaterials. These papers were presented in the environmental chemistry division that included topics of aggregation behavior of chiral single-walled carbon nanotubes and hybrid nanomaterials (Khan et al. and Aich and Saleh), deposition behavior of anisotroic gold nanomaterials (Afrooz et al), and antimicrobial effect of anisotropic gold nanomaterials (Afrooz et al).

Proceeding Details:

Afrooz, A. R. M. N., Aich, N., Khan, I. A., Saleh, N. B. "Deposition Behavior of Anisotropic Nanomaterials", ACS National Meeting, Aug 22-26, 2010, Boston, MA.

Khan, I. A., Ferguson, P. L., Sabo-Attwood, T., Saleh, N. B. "Systematic Change in Chirality Affects Aggregation Kinetics of Single-Walled Carbon Nanotubes", ACS National Meeting, Aug 22-26, 2010, Boston, MA.

Aich, N., Saleh, N. B. "Aggregation Kinetics of Fullerene-Single-walled Carbon Nanotube Hybrids", ACS National Meeting, Aug 22-26, 2010, Boston, MA.

Afrooz, A. R. M. N., Zaib, Q., Decho, A. W., Saleh, N. B. "Role of Nanoparticle Geometry on Nano-bio Interaction: A Quest to Separate Physics from Chemistry", ACS National Meeting, Aug 22-26, 2010, Boston, MA.


August 26, 2010 Dr. Sabo-Attwood presented a technical paper in SETAC-Clemson meeting. Saleh group is a key contributor to the research.

Dr. Tara Sabo-Attwood of Environmental Health Science Department of Arnold School of Public Health at the University of South Carolina has presented a research paper on immunomodulatory response of engineered nanomaterials at the Nano 2010 conference. This international conference was jointly organized by SETAC and Clemson University that was held from August 22-26, 2010 at Clemson, SC. Saleh Group works in close collaboration with Dr. Sabo-Attwood to decipher the mechanistic interaction of engineered nanoparticles with eukaryotic cells.

Proceeding Details:

Sabo-Attwood, T., Brusch-Richardson, L., Ariza, M. E., Khan, I. A., Saleh, N. B., "Assessment of Immunomodulatory Potential of Engineered Nanoparticles" Environmental Effects of Nanoparticles and Nanomaterials, SETAC-Clemson University, Aug 22-26, 2010, Clemson, SC.


August 26, 2010 A journal article in Langmuir has been published where Dr. Saleh is a co-author.

A journal article entitled "Multiwalled Carbon Nanotube Filter: Improving Viral Removal at Low Pressure" has recently been published in Langmuir where Dr. Saleh is a co-author. This paper focuses on the possibilities of cost-effective efficient virus removal processes using multiwalled carbon nanotubes filters.

Abstract:

The effective removal of viruses by a multiwalled carbon nanotube (MWNT) filter is demonstrated over a range of solution chemistries. MS2 bacteriophage viral removal by the MWNT filter was between 1.5 and 3 log higher than that observed with a recently reported single-walled carbon nanotube (SWNT) filter when examined under similar loadings (0.3 mg/cm2) of carbon nanotubes (CNTs). The greater removal of viruses by the MWNT filter is attributed to a more uniform CNT-filter matrix that allows effective removal of viruses by physicochemical (depth) filtration. Viral removal by the MWNT filter was examined under a broad range of water compositions (ionic strength, monovalent and divalent salts, solution pH, natural organic matter, alginate, phosphate, and bicarbonate) and filter approach velocities (0.0016, 0.0044, and 0.0072 cm/s). Log viral removal increased as the fluid approach velocity decreased, exhibiting a dependence on approach velocity in agreement with colloid filtration theory for Brownian particles. Viral removal improved with increasing ionic strength (NaCl), from 5.06 log removal at 1 mM NaCl to greater than 6.56 log removal at 100 mM NaCl. Addition of calcium ions also enhanced viral removal, but the presence of magnesium ions resulted in a decrease in viral removal. Solution pH also played an important role in viral removal, with log removals of 8.13, 5.38, and 4.00 being documented at solution pH values of 3.0, 5.5, and 9.0, respectively. Dissolved natural organic matter (NOM) had a negligible effect on viral removal at low concentration (1 mg/L), but higher concentrations of NOM significantly reduced the viral removal by the MWNT filter, likely due to steric repulsion. Addition of alginate (model polysaccharide) also caused a marked decrease in viral removal by the MWNT filter. This highly scalable MWNT-filter technology at gravity-driven pressures presents new, cost-effective options for point-of-use filters for viral removal.


Full Paper


August 01, 2010 Dr. Saleh presented an invited lecture, jointly hosted by departments of Civil and Chemical Engineering, BUET, Dhaka, Bangladesh.

Dr. Saleh presented a technical lecture titled "Applications and Implications of Nanotechnology". The seminar, held ITN Centre at Civil Bldg (BUET), was open for the faculties and students. In his speech Dr. Saleh addressed how the nanotechnology and nanomaterials can be applied to solve environmental and health problems. The seminar was followed by a lively discussion session with audience. Read More


July 16, 2010 Dr. Saleh presented a technical paper in the Clemson Carbon conference.

As a lead researcher in the study of the environmental impact of the carbon based nanomaterials Dr. Saleh was invited to present in the international conference on carbon nano- and macro-scale materials held at Clemson University, Clemson, SC from July 11-16, 2010. Dr. Saleh presented experimental and theoretical insight into the fundamental aggregation and deposition behavior of carbon nanotubes in aquatic environment.

Proceeding Details:

Saleh, N. "Aggregation and Deposition Behavior of Carbon Nanotubes in Aquatic Environments" Clemson Carbon Conference, July 11-16, 2010, Clemson, SC.


July 9, 2010 Dr. Saleh nominated for Marquis Who's Who in Science and Engineering.

Marquis Who's Who has nominated Dr. Saleh for Who's Who in Science and Engineering 2011-2012. Marquis Who's Who is the premiere biographer for American leaders in academia and industry since 1899. This honor is awarded to listees with significant contribution to their respective fields.


July 1, 2010 Saleh Group has been awarded a grant by the USC Nanocenter amounting $20,000.

Saleh Group has been awarded a grant by USC Nanocenter to establish the first of its kind study of environmental fate and transport of hybrid nanomaterials. The project will be accomplished in joint collaboration with Dr. Harry Dorn in Virginia Tech. Read more on the project in our research page.


May 1, 2010 Saleh Group is awarded a grant by GSE&C amounting $220,000. Dr. Saleh is a Co-PI in the grant.

Saleh Group has been awarded a grant by Goldstar E&C, Korea, to study effect of carbon nanotubes in removing endocrine disrupting compounds from wastewater. Dr. Saleh, a Co-PI in the project, is a key contributor to the nanomaterial characterization, functionalization, and use. The project will be accomplished in joint collaboration with Drs. Yeomin Yoon (PI) and Joseph Flora (Co-PI) in USC. Read more on the project in our research page.


March 11, 2010 Leslyn Brusch-Richardson has presented a paper in the 49th Annual Meeting of Society of Toxicology, held at Salt lake City, UT. Saleh group is a key contributor in the study.

Leslyn Brusch-Richardson, a co-advised student of Drs. Navid Saleh and Tara Sabo-Attwood has presented a research paper on immunomodulatory response of engineered nanomaterials at the Society of Toxicology (SOT) Annual meeting held at Salt Lake City, UT from March 07-11, 2010. Saleh Group works in close collaboration with Dr. Sabo-Attwood to decipher the mechanistic interaction of engineered nanoparticles with eukaryotic cells.

Proceeding Details:

Brusch-Richardson, L., Ariza, M. E., Saleh, N. B., Sabo-Attwood, T. "Development of a High Throughput Assay to Assess the Immunomodulatory Potential of Engineered Nanoparticles" Society of Toxicology 49th Annual Meeting, March 07-11, 2010, Salt lake City, UT.


February 25, 2010 Saleh Group has published a paper in Environ. Sci. Technol. Dr. Saleh is the lead author in the paper.

A journal article titled "Influence of Biomacromolecules and Humic Acid on Aggregation Kinetics of Single-Walled Carbon Nanotubes" has recently been published in Environmental Science & Technology that studies aggregation behavior of single-walled carbon nanotubes (SWNTs) in natural organic matter and biomacromolecules of biological and environmental relevance. The study chose humic acid, bovine serum albumin (BSA), Luria broth (LB), and alginate as the natural and biological macromolecules to study the aggregation kinetics of SWNTs.

Abstract

The initial aggregation kinetics of single-walled carbon nanotubes (SWNTs) were studied using time-resolved dynamic light scattering. Aggregation of SWNTs was evaluated in the presence of natural organic matter [Suwannee River humic acid (SRHA)], polysaccharide (alginate), protein [bovine serum albumin (BSA)], and cell culture medium [Luria-Bertani (LB) broth] with varying solution concentrations of monovalent (NaCl) and divalent (CaCl2) salts. Increasing salt concentration and adding divalent calcium ions induced SWNT aggregation by screening electrostatic charge and thereby suppressing electrostatic repulsion, similar to observations with aquatic colloidal particles. The presence of biomacromolecules significantly retarded the SWNT aggregation rate. BSA protein molecules were most effective in reducing the rate of aggregation followed by SRHA, LB, and alginate. The slowing of the SWNT aggregation rate in the presence of the biomacromolecules and SRHA can be attributed to steric repulsion originating from the adsorbed macromolecular layer. The remarkably enhanced SWNT stability in the presence of BSA, compared to that with the other biomacromolecules and SRHA, is ascribed to the BSA globular molecular structure that enhances steric repulsion. The results have direct implications for the fate and behavior of SWNTs in aquatic environments and biological media.


Full Paper

October 1, 2009 Saleh Group has been awarded an NSF grant from the CBET directorate amounting $400,000. Dr. Saleh is the PI in the grant.

Saleh Group has received a grant in the amount of $400,000, funded by the CBET directorate of the National Science Foundation. The project is titled "Influence of diameter and chirality of single-walled carbon nanotubes on their fate and effects in the aquatic environment". Read more on this grant in our research page.


April 8, 2009 A journal article in Environ Sci and Technol has been published where Dr. Saleh is a co-author.

A journal article titled "Effect of Adsorbed Polyelectrolytes on Nanoscale Zero Valent Iron Particle Attachment to Soil Surface Models" has recently been published in Environmental Science & Technology which discusses the effect of coatings on the interaction of nanoscale zerovalent iron (NZVI) and soil surface. Dr. Saleh is a co-author in this paper.

Abstract

Polyelectrolyte coatings significantly increase the mobility of nanoscale zerovalent iron (NZVI) in saturated porous media. The effect can be attributed to improved colloidal stability of NZVI suspensions, decreased adhesion to soil surfaces, or a combination of the two effects. This research explicitly examines how coatings control NZVI adhesion to model soil surfaces. NZVI was coated with three different polyelectrolyte block copolymers based on poly(methacrylic acid), poly(methyl methacrylate or butyl methacrylate), and poly(styrenesulfonate) or with a poly(styrenesulfonate) homopolymer. SiO2 and a humic acid film served as model soil surfaces. The polyelectrolytes increased the magnitude of the electrophoretic mobility of NZVI over a broad pH range relative to unmodified NZVI and shifted the isoelectric point outside the typical groundwater pH range. Quartz crystal microgravimetry measurements indicated extensive adhesion of unmodified NZVI to SiO2. Polyelectrolyte coatings decreased adhesion by approximately 3 orders of magnitude. Adding 50 mM NaCl to screen electrostatic repulsions did not significantly increase adhesion of modified NZVI. Coated NZVI did not adhere to humic acid films for either 1 mM NaHCO3 or 1 mM NaHCO3 + 50 mM NaCl. The lack of adhesion even in a high ionic strength medium was attributed to electrosteric repulsion, as opposed to electrostatic double layer repulsion, between the polyelectrolyte-coated NZVI and the negatively charged surfaces. The lack of significant adhesion on either model surface was observed for all polymer architectures investigated.


Full Paper