分别制备了以L-半胱氨酸(L-cyst.)或以巯基乙酸(TGA)保护的银纳米颗粒,并用紫外-可见分光光度法和透射电子显微技术(TEM)对两种不同状态的银纳米颗粒的结构作了表征。由其吸收光谱图显示,L-cyst.和TGA保护的银纳米颗粒的吸收峰依次位于384 nm和392 nm波长处;由TEM的检测结果表明:上述2种形态银纳米颗粒的粒度大小依次在10~40 nm和20~30 nm范围内。试验中发现,以L-cyst.保护的银纳米颗粒与曙红Y之间有明显的相互作用,导致其吸收峰从384 nm红移至395 nm;以TGA保护的银纳米颗粒与曙红Y之间未见有相互反应。初步探讨了其作用机理,认为系由于结合于银纳米颗粒表面的L-半胱氨酸分子所带的正电荷与曙红Y分子上的负电荷之间的静电作用的结果。

Silver nanoparticles were prepared under the protection of either L-cysteine (L-cyst.) or thioglycollic acid (TGA). The structures of these 2 different states of silver nanoparticles were characterized by UV-VIS spectrophotometry and transmission electron microscope (TEM). As shown by the UV-VIS absorption spectra, absorption maxima at 384 nm and 392 nm were found for the L-cyct.-protected and TGA-protected silver nanoparticles respectively. It was shown by the results of TEM study, the sizes of the L-cyst.-protected and TGA-protected Ag-nanoparticles were found in the ranges of 10-40 nm and 20-30 nm respectively. It was found that significant interaction was observed between the L-cyst.-protected Ag-nanoparticles and eosin Y, giving a bathochromic shift of absorption maximum from 384 nm to 395 nm; and that no interaction between the TGA-protected Ag-nanoparticles and eosin Y was observed. Electrostatic action between the positively charged L-cyst. molecules at the surface of Ag-nanoparticles and the negatively charged eosin Y molecules was proposed as the chemism of the interaction.