Department of Chemistry, Howard University, Washington, DC 20059, USA.
J Colloid Interface Sci. 2013 Jul 15;402:40-9. doi: 10.1016/j.jcis.2013.03.018. Epub 2013 Apr 2.
The primary objective of this study is to investigate the interactive forces that promote the adsorption of bio-conjugated nanoparticles onto proteins. To elucidate the interactive forces, we demonstrate an approach using synthetic and model biological surfaces to study adsorption of bio-conjugated nanoparticles. Real-time adsorption of BSA conjugated silver nanoparticles (Ag/BSA NPs) on the immobilized substrates was followed by surface plasmon resonance (SPR). The extent of adsorption of the nanoparticles on the synthetic surface was found to be larger for self-assembled monolayers (SAMs) with ionizable terminal groups and lower for SAMs with unionizable terminal groups. For model biological substrate, the extent of nanoparticles adsorption was found to relate to the pKa of immobilized proteins. For collagen immobilized substrate, the adsorption of Ag/BSA nanoparticles showed a significantly higher SPR response than that of free BSA. The extent of nanoparticles adsorption on the collagen immobilized substrate was also influenced by the type and concentration of electrolyte used in dispersing nanoparticles. Our findings indicate that the adsorption of nanoparticles to immobilized surface has contributions from electrostatic interactions, hydrophobic, and/or hydrogen bonding. This work provides the framework to study interactions that may arise when bio-conjugated nanoparticles are transported in biological systems.
本研究的主要目的是研究促进生物共轭纳米粒子吸附到蛋白质上的相互作用力。为了阐明相互作用力，我们展示了一种使用合成和模型生物表面来研究生物共轭纳米粒子吸附的方法。通过表面等离子体共振（SPR）实时跟踪 BSA 共轭银纳米粒子（Ag/BSA NPs）在固定化基底上的吸附。研究发现，带有可离子化端基的自组装单层（SAMs）对纳米粒子的吸附程度较大，而带有不可离子化端基的 SAMs 则较小。对于模型生物底物，纳米粒子的吸附程度与固定化蛋白质的 pKa 有关。对于胶原蛋白固定化底物，Ag/BSA 纳米粒子的吸附显示出比游离 BSA 更高的 SPR 响应。纳米粒子在胶原蛋白固定化基底上的吸附程度也受到分散纳米粒子所用电解质的类型和浓度的影响。我们的研究结果表明，纳米粒子在固定化表面上的吸附来自于静电相互作用、疏水性和/或氢键。这项工作为研究生物共轭纳米粒子在生物系统中运输时可能产生的相互作用提供了框架。
