Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Colloids Surf B Biointerfaces. 2013 Feb 1;102:879-83. doi: 10.1016/j.colsurfb.2012.10.007. Epub 2012 Oct 13.
The formation and growth of hybrid nanoparticles of a protein BSA and silver by ultrasonic assistance were tracked by surface plasmon resonance signal of silver nanoparticles and light scattering. The hybrid nanoparticles were characterized by surface plasmon resonance spectra, light scattering, TEM, circular dichroism spectroscopy and zeta potential. Size along with the spherical shape of the nanoparticles could be controlled and nanoparticles with diameters ranging from 8 to 140 nm could be obtained, depending upon the ultrasonication time (15-30 min) and molar ratio of AgNO(3)/BSA (20-200). The role of single free thiol group in the reduction of silver ions was also investigated by using DTNB modified BSA and protein conjugated silver nanoparticles were formed even with thiol modified BSA. The growth and size of the nanoparticles were governed by ultrasonic assisted Ostwald ripening. BSA conjugated with silver nanoparticles showed changes in the secondary structure with an increase in the beta sheet structure to 33% as compared to 7% in native BSA as determined by CD spectra. Zeta potential measurements in the pH range of 2.0-12.0 demonstrated that the surface charges of the BSA conjugated silver nanoparticles were similar to that of native BSA suggesting that surface charges and overall three dimensional structure of BSA did not change much. This approach provides a strategy for completely green synthesis of hybrid nanoparticles consisting of a biological entity and an inorganic material. This is the first application of ultrasonic assistance in formation of such hybrid nanomaterials in aqueous media.
超声辅助下蛋白质 BSA 和银形成和生长的杂交纳米粒子通过银纳米粒子的表面等离子体共振信号和光散射进行跟踪。杂交纳米粒子通过表面等离子体共振光谱、光散射、TEM、圆二色光谱和zeta 电位进行表征。可以控制纳米粒子的大小和形状，得到的纳米粒子直径范围为 8 至 140nm，这取决于超声时间（15-30min）和 AgNO(3)/BSA 的摩尔比（20-200）。还通过使用 DTNB 修饰的 BSA 研究了单个游离巯基在还原银离子中的作用，即使使用巯基修饰的 BSA 也可以形成蛋白质共轭的银纳米粒子。纳米粒子的生长和大小受超声辅助的奥斯特瓦尔德熟化控制。与天然 BSA 相比，与银纳米粒子结合的 BSA 显示出二级结构的变化，β片层结构增加到 33%，而天然 BSA 中只有 7%。在 pH 值为 2.0-12.0 的范围内进行的 zeta 电位测量表明，BSA 共轭银纳米粒子的表面电荷与天然 BSA 的表面电荷相似，这表明表面电荷和 BSA 的整体三维结构没有太大变化。该方法为完全绿色合成由生物实体和无机材料组成的杂交纳米粒子提供了一种策略。这是超声辅助在水相介质中形成此类杂交纳米材料的首次应用。
