Nagasaki Y, Kataoka K
Department of Materials Science, Tokyo University of Science, Noda 278-8510, Japan.
IEE Proc Nanobiotechnol. 2005 Apr;152(2):89-96. doi: 10.1049/ip-nbt:20055021.
The synthesis of poly(ethylene glycol)-b-poly(2-N,N-dimethylaminoethylmethacrylate) processing an acetal group at the PEG chain end (acetal-PEGPAMA) is reported. The obtained acetal-PEGPAMA block copolymer was found to reduce tetrachloroauric acid at room temperature to produce gold nanoparticles. The size of these nanoparticles was controllable in the range of 6 to 13 nm by changing the initial Au3+: polymer ratio. In addition to the reduction of tetrachloroauric acid, acetal-PEGPAMA bonds on the surface of the obtained gold nanoparticles to improve their dispersion stability in an aqueous medium even at a salt concentration as high as two. Biotinyl-PEGPAMA-anchored gold nanoparticles undergo specific aggregation in the presence of streptavidin thereby revealing their promising utility as colloidal sensing systems for use in biological systems. Biotin-PEGPAMA can also be utilised for the preparation of a functionally PEGylated quantum dot (QD). When CdCl2 and Na2S were mixed in aqueous media in the presence of the biotin-PEGPAMA, a CdS QD with an approximately 5 nm size was prepared. The polyamine segment was anchored onto the surface of the formed CdS nanoparticle, whereas the PEG segment was tethered onto the surface to form a hydrophilic palisade, thus improving the dispersion stability in aqueous media even under a high salt concentration condition. An effective fluorescent resonance energy transfer (FRET) was observed by the specific interaction of the biotin-PEGPAMA stabilised CdS QD with TexasRed-labelled streptavidin with the physiological ionic strength of 0.15 M. The extent of the energy transfer was in proportion to the concentration of the TexasRed-streptavidin. This FRET system using the PEGylated CdS QD coupled with fluorescent-labelled protein can be utilised as a highly sensitive bioanalytical system.
报道了在聚乙二醇（PEG）链端带有缩醛基团的聚（乙二醇）-b-聚（2-N，N-二甲基氨基乙基甲基丙烯酸酯）（缩醛-PEGPAMA）的合成。发现所得到的缩醛-PEGPAMA嵌段共聚物在室温下能还原氯金酸以制备金纳米颗粒。通过改变初始Au3+与聚合物的比例，这些纳米颗粒的尺寸可在6至13nm范围内控制。除了还原氯金酸外，所得到的金纳米颗粒表面的缩醛-PEGPAMA键可提高其在水介质中的分散稳定性，即使在盐浓度高达2时也是如此。生物素化的PEGPAMA锚定的金纳米颗粒在链霉亲和素存在下会发生特异性聚集，从而显示出其作为用于生物系统的胶体传感系统的潜在用途。生物素-PEGPAMA还可用于制备功能化的聚乙二醇化量子点（QD）。当在生物素-PEGPAMA存在下于水介质中混合CdCl2和Na2S时，制备了尺寸约为5nm的CdS QD。多胺链段锚定在形成的CdS纳米颗粒表面，而PEG链段则连接在表面形成亲水性栅栏，从而即使在高盐浓度条件下也能提高在水介质中的分散稳定性。在生理离子强度为0.15M的条件下，通过生物素-PEGPAMA稳定的CdS QD与TexasRed标记的链霉亲和素的特异性相互作用，观察到了有效的荧光共振能量转移（FRET）。能量转移的程度与TexasRed-链霉亲和素的浓度成正比。这种使用聚乙二醇化CdS QD与荧光标记蛋白相结合的FRET系统可作为一种高灵敏度的生物分析系统。
