中文摘要：

目的 利用核酸适配体（aptamer）建立一种检测与疾病有关蛋白质的新方法。方法 用金纳米颗粒（AuNP）修饰的寡核苷酸适配子与蛋白质结合，同时另一个生物素化的寡核苷酸适配子也结合于蛋白质，构成一个三明治形式的复合物，接着三明治复合物被卵白素结合于酶标板上，利用银离子强化技术对复合物上的蛋白质浓度信息进行放大，然后用酶标仪对吸光度进行检测。结果（1）本研究可以得到吸光度与PDGF—BB浓度的剂量一效应关系曲线，在一定的浓度范围内（1fM～1μM），吸光度与PDGF—BB浓度的对数值呈线形相关，决定系数R^2=0．9801；（2）本方法可以检测出1fmol／L的靶蛋白质。结论本方法有较高灵敏度，不需要复杂的仪器，易于操作，是一种新颖而应用前景的蛋白质标志物分析方法。

英文摘要：

Objective An ultrasensitive colorimetric method for detecting protein by nanoparticle-modified aptamer was established. Methods In this assay, target protein was bound to nanoparticle-modified aptamer and another aptamer probe modified with biotion together forming a sandwich-like complex. Thereafter, the sandwichlike complex was captured in microwell by avidin. After amplification by silver-enhancement, the absorbance resulted from aptamer-protein complex was determined by colorimetry. Results In the range of 1fM- 1μM, the absorbance induced by the concentration of PDGF was dose-dependent, R^2=0. 9801. The minimal detection limit was lfM of targeted protein. Conclusion this new NP-modified aptamer assay could offer an ultrasensitive detection for protein. It requires no complicated or expensive instrument and is easy to use. It has a good future for detecting ultratrace level of disease-related protein markers that can not be detected by conventional methods.