Subscriber access provided by University of Otago Library
Article
Zeta Potential (#) for Metal Oxide Nanoparticles: A Predictive Model Developed by Nano-QSPR Approach Alicja Mikolajczyk, Agnieszka Gajewicz, Bakhtiyor Rasulev, Nicole Schaeublin, Elisabeth Maurer-Gardner, Saber M. Hussain, Jerzy Leszczynski, and Tomasz Puzyn Chem. Mater., Just Accepted Manuscript • DOI: 10.1021/cm504406a • Publication Date (Web): 09 Mar 2015 Downloaded from http://pubs.acs.org on March 16, 2015
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Chemistry of Materials is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 11
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Chemistry of Materials
Zeta Potential (ζ) for Metal Oxide Nanoparticles: A Predictive Model Developed by Nano-QSPR Approach †
†
Alicja Mikolajczyk , Agnieszka Gajewicz , Bakhtiyor Rasulev§,‡, Nicole Schaeublin¶, † Elisabeth Maurer-Gardner¶, Saber Hussain¶, Jerzy Leszczynski§ and Tomasz Puzyn * †
Laboratory of Environmental Chemometrics, Institute for Environmental and Human Health Protection, Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland § Interdisciplinary Nanotoxicity Center, Department of Chemistry and Biochemistry, Jackson State University, Jackson, 39217-0510 Mississippi, USA ‡ Center for Computationally Assisted Science and Technology, North Dakota State University, NDSU Research Park Dr, P.O. Box 6050, Fargo, ND 58108, USA ¶ Biological Interaction of Nanomaterials, Applied Biotechnology Branch, Human Effectiveness Directorate 711th, Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base OH, USA
ABSTRACT: Physico-chemical characterization of nanoparticles in the context of theirs transport and fate in the environment is an important challenge for risk assessment of nanomaterials. One of the main characteristics that define the behavior of nanoparticles in solution is zeta potential (ζ). In this paper we have demonstrated the relationship between zeta potential and a series of intrinsic physico-chemical features of 15 metal oxide nanoparticles revealed by computational study. The developed here Quantitative Structure-Property Relationship model (nano-QSPR) was capable to predict ζ of metal oxide nanoparticles utilizing only two descriptors: (i) the spherical size of nanoparticles – a parameter from numerical analysis of Transmission Electron Microscopy (TEM) images and (ii) the energy of the highest occupied molecular orbital per metal atom - a theoretical descriptor calculated by quantum mechanics at semiempirical level of theory (PM6 method). The obtained consensus model is characterized by reasonably well predictivity (Q2ext=0.87). Therefore, the developed model can be utilized to in silico evaluation of properties of novel engineered nanoparticles. This study is a first step in developing a comprehensive and computationally-based system to predict physico-chemical properties that are responsible for aggregation phenomena in metal oxide nanoparticles.
1 ACS Paragon Plus Environment
Chemistry of Materials
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 11
There are also additional factors influencing agglomeration/aggregation phenomena come into play when serum is introduced to the cell culture media. The proteins in the serum can both discourage agglomeration of some nanoparticles after dispersion4a, as well as cause nanoparticle agglomeration due to the adsorption of serum proteins onto the surface.4c The formation of the corona is a complex and dynamic phenomenon, which requires considerable more research in order to elucidate not only the factors that contribute to its formation, but also, how it may affect the agglomeration of nanoparticles. Numerous studies have attempted to address the characterization and evaluation of nanoparticles behavior experimentally. Experimental evaluation of nanoparticles’ interactions with biological systems is expensive and timeconsuming. Thus, there is an increased interest in the application of faster and much less expensive computational techniques such as Quantitative Structure-Property Relationship (QSPR) models. The use of QSPR not only eliminates the need of extensive experimental testing, but, in addition, provides valuable suggestions on the mechanism of the studied phenomena at the molecular level.1, 7 Our group previously investigated various nanoparticles’ properties, and developed efficient nano-QSAR and nano-QSPR models.1, 7b, 7c, 8 In this work we applied the nano-QSPR approach together with novel nano-structural descriptors derived from Transmission Electron Microscopy (TEM) images to describe relationships between zeta potential (ζ) and structural features of 15 metal oxide nanoparticles (MeOxNPs).
INTRODUCTION
Apart from many benefits related to wide application of nanomaterials in every-day-life products, rapidly developing nanotechnology may result in many serious threats such as environmental contamination and possible human health problems. Thus, designing of new nanomaterials should be always accompanied by a comprehensive risk assessment.1 Toxicity of nanoparticles to living organisms depends on various structural features (intrinsic properties), such as: chemical composition, crystalline form, size, shape, porosity, surface area, and surface chemistry.2 Accordingly to changes in the dispersing environment, nanoparticles can rapidly agglomerate and in effect, form particles having large diameters. On the contrary, when the organism uptakes an agglomerate of nanoparticles from the environment, depending on the biological conditions (mainly pH) the agglomerate may dissociate and like a “Trojan horse”, becomes a source of much smaller (often also more toxic) particles in the body.3 Thus, the agglomeration phenomenon largely influences toxicity of nanoparticles.4 Such properties of nanoparticles that describe their behavior are known as extrinsic properties. The ease of formation of agglomerates strongly depends on the surface charge that stabilizes dispersed nanoparticles and prevents them from agglomeration. However, the available experimental techniques are unable to measure surface charge directly; its value can only be estimated by measuring zeta potential (ζ) in a given media.4b Therefore, zeta potential (ζ) (in the limit of ZP ± 30 eV) is an extremely important parameter in determining stability of nanoparticles in complex media. Theoretical and experimental results have confirmed that zeta potential (ζ) is affected not only by the suspension conditions such as pH, temperature, ionic strength, and even the types of ions, but also by the intrinsic particle properties such as size and concentration, respectively.4b, 5 Zeta potential has been used to diagnose the cellular interaction with charged ions or molecules. It was shown that the presence of negatively charged ions or molecules decreases the surface zeta potential and, on the contrary, the presence of positively charged ions increases the surface zeta potential.6
EXPERIMENTAL SECTION Nanoparticles and characterization. Data containing the experimental values of zeta potential (endpoint) of selected 15 MeOx NPs (Table 1), which were acquired from our previous study where human keratinocyte cell line (HaCaT) was investigated.8d To verify morphology and size, one drop of a 100 µg/mL solution (RPMI-1640 media, at pH = 7.5 (ATCC, Manassas, VA), supplemented with 10% (v/v) fetal bovine serum (FBS, ATCC) and 1% (w/v) penicillin/streptomycin (Sigma, St. Louis, MO) was spotted on a forever/carbon-coated TEM grid (EMS Diasum, Hatfield, PA) and allowed to dry.
Table 1. Sumary characterization of data used in the study MeOx NPs V2O3 Al2O3 Fe2O3 Sb2O3 La2O3 ZnO Y2O3 SnO2 In2O3 TiO2 WO3 ZrO2 SiO2 CoO Bi2O3
Particle size (nm) n/a 44.0 32.0 90.0-210.0 46.0 71.0 38.0 46.1 29.8 42.3 30.0-70.0 46.7 15.0
