Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Langmuir. 2011 Aug 16;27(16):10167-73. doi: 10.1021/la201291k. Epub 2011 Jul 12.
The interaction of lysozyme protein (M.W. 14.7 kD) with two sizes of silica nanoparticles (16 and 25 nm) has been examined in aqueous solution using UV-vis spectroscopy and small-angle neutron scattering (SANS). The measurements were performed on fixed concentration (1 wt %) of nanoparticles and varying concentration of protein in the range 0 to 2 wt %. The adsorption isotherm as obtained using UV-vis spectroscopy suggests strong interaction of the two components and shows an exponential behavior. The saturation values of adsorption are found to be around 90 and 270 protein molecules per particle for 16 and 25 nm sized nanoparticles, respectively. The adsorption of protein on nanoparticles leads to the aggregation of particles and these structures have been studied by SANS. The aggregates are characterized by fractal structure coexisting with unaggregated particles at low protein concentrations and free proteins at higher protein concentrations. Further, contrast variation SANS measurements have been carried out to differentiate the adsorbed and free protein in these systems.
溶菌酶蛋白（分子量 14.7kD）与两种尺寸的二氧化硅纳米颗粒（16nm 和 25nm）在水溶液中的相互作用已通过紫外-可见光谱和小角中子散射（SANS）进行了研究。测量是在固定浓度（1wt%）的纳米颗粒和变化的蛋白浓度范围为 0 至 2wt%下进行的。紫外-可见光谱得到的吸附等温线表明两种组分之间存在强烈的相互作用，并呈现出指数行为。对于 16nm 和 25nm 大小的纳米颗粒，分别发现吸附的饱和值约为 90 和 270 个蛋白分子/颗粒。纳米颗粒上的蛋白吸附导致颗粒的聚集，这些结构已通过 SANS 进行了研究。聚集物的特征是分形结构与低蛋白浓度下未聚集的颗粒共存，以及高浓度下的游离蛋白共存。此外，还进行了对比变化 SANS 测量，以区分这些体系中的吸附蛋白和游离蛋白。
