title: Study on aggregation behavior of Cytochrome C-conjugated silver nanoparticles using asymmetrical flow field-flow fractionation.
abstract: In this study, 40 nm silver nanoparticles (AgNPs) were synthesized using the citrate reduction method and then the surface of AgNPs was modified by conjugating Cytochrome C (Cyto C) to improve stability and to enhance bioactivity and biocompatibility of AgNPs. It is known that Cyto C may undergo conformational changes under various conditions of pH, temperature, ionic strength, etc., resulting in aggregation of the particles. These parameters also affect the size and size distribution of Cyto C-conjugated AgNPs (Cyto C-AgNP). ζ-potential measurement revealed that the adsorption of Cyto C on the surface of AgNPs is saturated at the molar ratio [Cyto C]/[AgNPs] above about 300. Asymmetrical flow field-flow fractionation (AsFlFFF) analysis showed that hydrodynamic diameter of AgNPs increases by about 4 nm when the particle is saturated by Cyto C. The aggregation behavior of Cyto C-AgNP at various conditions of pH, temperature and ionic strength were investigated using AsFlFFF and UV-vis spectroscopy. It was found that the aggregation of Cyto C-AgNP increases with decreasing pH, increasing temperature and ionic strength due to denaturation of Cyto C on AgNPs and reduction in the thickness of electrostatic double layer on the surface of Cyto C-AgNP.
authors.affiliation: Department of Chemistry, Hannam University, Daejeon 305-811, South Korea.
authors.forename: Sun Tae
authors.initials: ST
authors.lastname: Kim
authors.affiliation: Gyungnam Department of Environmental Toxicology, Korea Institute of Toxicology, Jinju 660-844, South Korea.
authors.forename: Yong-Ju
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Gyungnam Department of Environmental Toxicology, Korea Institute of Toxicology, Jinju 660-844, South Korea.
authors.forename: Yu-Sik
authors.initials: YS
authors.lastname: Hwang
authors.affiliation: Department of Chemistry, Hannam University, Daejeon 305-811, South Korea. Electronic address: slee@hannam.kr.
authors.forename: Seungho
authors.initials: S
authors.lastname: Lee
mesh_terms: D019343:Citric Acid / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry*; D055664:Electrochemical Techniques; D031521:Fractionation, Field Flow / Q000295:instrumentation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010316:Particle Size; D066329:Protein Aggregates; D011485:Protein Binding; D011487:Protein Conformation; D012834:Silver / Q000737:chemistry*; D055672:Static Electricity; D013696:Temperature
chemical_list: D066329:Protein Aggregates; D019343:Citric Acid; D012834:Silver; D045304:Cytochromes c
keywords: Aggregation; Asymmetrical flow field-flow fractionation (AsFlFFF); Cytochrome C–conjugated AgNPs; UV–vis spectroscopy; ζ-potential