Browsing by Subject "Zeta potential"
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Item Open Access Biocompatibility studies on lanthanum oxide nanoparticles(Royal Society of Chemistry, 2015) Brabu, B.; Haribabu, S.; Revathy, M.; Anitha, S.; Thangapandiyan, M.; Navaneethakrishnan, K. R.; Gopalakrishnan, C.; Murugan, S. S.; Kumaravel, T. S.Lanthanum oxide nanoparticles (LONP), a rare earth metal oxide, have unique properties that make them a suitable candidate for several biomedical applications. We investigated certain key in vitro and in vivo biocompatibility endpoints on LONP. LONP were cytotoxic in in vitro assays and predominantly exerted their action via release of reactive oxygen species. These nanoparticles were neither irritants nor sensitizers in a rabbit model. LONP extracts did not exert any acute systemic toxicity effects in mice. On the other hand LONP exerted toxicity to the liver following oral administration, suggesting that these particles are absorbed from the gastrointestinal (GI) tract and deposited in the hepatobiliary system. LONP did not induce any mutation in the Ames test both in the presence or absence of S-9. These observations provide a base line biocompatibility and toxicity data on LONP. The current findings will also be useful in defining standards for nanoparticle containing devices. © The Royal Society of Chemistry.Item Open Access Electrostatic effects on nanofiber formation of self-assembling peptide amphiphiles(Elsevier, 2011) Toksoz, S.; Mammadov R.; Tekinay, A. B.; Güler, Mustafa O.Self-assembling peptide amphiphile molecules have been of interest to various tissue engineering studies. These molecules self-assemble into nanofibers which organize into three-dimensional networks to form hydrocolloid systems mimicking the extracellular matrix. The formation of nanofibers is affected by the electrostatic interactions among the peptides. In this work, we studied the effect of charged groups on the peptides on nanofiber formation. The self-assembly process was studied by pH and zeta potential measurements, FT-IR, circular dichroism, rheology, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. The aggregation of the peptides was triggered upon neutralization of the charged residues by pH change or addition of electrolyte or biomacromolecules. Understanding the controlled formation of the hydrocolloid gels composed of peptide amphiphile nanofibers can lead us to develop in situ gel forming bioactive collagen mimetic nanofibers for various tissue engineering studies including bioactive surface coatings. © 2010 Elsevier Inc.Item Open Access Glycosaminoglycan-Mimetic Signals Direct the Osteo/Chondrogenic Differentiation of Mesenchymal Stem Cells in a Three-Dimensional Peptide Nanofiber Extracellular Matrix Mimetic Environment(American Chemical Society, 2016-02) Arslan, E.; Güler, Mustafa O.; Tekinay, A. B.Recent efforts in bioactive scaffold development focus strongly on the elucidation of complex cellular responses through the use of synthetic systems. Designing synthetic extracellular matrix (ECM) materials must be based on understanding of cellular behaviors upon interaction with natural and artificial scaffolds. Hence, due to their ability to mimic both the biochemical and mechanical properties of the native tissue environment, supramolecular assemblies of bioactive peptide nanostructures are especially promising for development of bioactive ECM-mimetic scaffolds. In this study, we used glycosaminoglycan (GAG) mimetic peptide nanofiber gel as a three-dimensional (3D) platform to investigate how cell lineage commitment is altered by external factors. We observed that amount of fetal bovine serum (FBS) presented in the cell media had synergistic effects on the ability of GAG-mimetic nanofiber gel to mediate the differentiation of mesenchymal stem cells into osteogenic and chondrogenic lineages. In particular, lower FBS concentration in the culture medium was observed to enhance osteogenic differentiation while higher amount FBS promotes chondrogenic differentiation in tandem with the effects of the GAG-mimetic 3D peptide nanofiber network, even in the absence of externally administered growth factors. We therefore demonstrate that mesenchymal stem cell differentiation can be specifically controlled by the combined influence of growth medium components and a 3D peptide nanofiber environment.Item Open Access Zeta potential: A surface electrical characteristic to probe the interaction of nanoparticles with normal and cancer human breast epithelial cells(Springer New York LLC, 2008) Zhang, Y.; Yang, M.; Portney, N. G.; Cui, D.; Budak, G.; Özbay, Ekmel; Ozkan, M.; Ozkan, C. S.We demonstrate the use of surface Zeta potential measurements as a new tool to investigate the interactions of iron oxide nanoparticles and cowpea mosaic virus (CPMV) nanoparticles with human normal breast epithelial cells (MCF10A) and cancer breast epithelial cells (MCF7) respectively. A substantial understanding in the interaction of nanoparticles with normal and cancer cells in vitro will enable the capabilities of improving diagnostic and treatment methods in cancer research, such as imaging and targeted drug delivery. A theoretical Zeta potential model is first established to show the effects of binding process and internalization process during the nanoparticle uptake by cells and the possible trends of Zeta potential change is predicted for different cell endocytosis capacities. The corresponding changes of total surface charge of cells in the form of Zeta potential measurements were then reported after incubated respectively with iron oxide nanoparticles and CPMV nanoparticles. As observed, after MCF7 and MCF10A cells were incubated respectively with two types of nanoparticles, the significant differences in their surface charge change indicate the potential role of Zeta potential as a valuable biological signature in studying the cellular interaction of nanoparticles, as well as specific cell functionality.