Cholesterol is an essential ingredient in mammals, and serum cholesterol is a major component of atherosclerotic plaques. The level of cholesterol in human serum has become an important index for clinical diagnosis and prevention of cardiovascular disease. In this paper, a simple and ultrasensitive cholesterol biosensor based on graphene oxide (GO) and gold nanoparticles (Au NPs) co-mediated enzymatic silver deposition was designed by immobilizing cholesterol oxidase (CHOD), cholesterol esterase (CHER) and GO onto the surface of Au NPs modified screen-printed carbon electrode (SPE). Under the synergistic effect of CHER, CHOD and GO, the cholesterol was hydrolyzed to generate hydrogen peroxide, which can reduce the silver (Ag) ions in the solution to metallic Ag which deposited on the surface of Au NPs modified SPE. The ultrasensitive detection of cholesterol was achieved by anodic stripping voltammetry measurement of the enzymatically deposited Ag. Under optimal conditions, the anodic stripping peak current of Ag increased with the increasing cholesterol concentration in the range from 0.01 μg/mL to 5000 μg/mL with a limit of detection of 0.001 μg/mL (S/N = 3). In addition, the ultrasensitive cholesterol biosensor exhibited higher specificity, acceptable reproducibility and excellent recoveries for cholesterol detection.

胆固醇是哺乳动物中必不可少的成分，血清胆固醇是动脉粥样硬化斑块的主要成分。人血清中的胆固醇水平已成为临床诊断和预防心血管疾病的重要指标。本文通过将胆固醇氧化酶（CHOD），胆固醇酯酶（CHER）和GO固定在表面上，设计了一种基于氧化石墨烯（GO）和金纳米颗粒（Au NPs）共同介导的酶促银沉积的简单且超灵敏的胆固醇生物传感器。 Au NPs修饰的丝网印刷碳电极（SPE）的制造。在CHER，CHOD和GO的协同作用下，胆固醇被水解生成过氧化氢，该过氧化氢可以将溶液中的银（Ag）离子还原为沉积在Au NPs改性SPE表面的金属Ag。胆固醇的超灵敏检测是通过阳极溶出伏安法测定酶促沉积的银来实现的。在最佳条件下，Ag的阳极溶出峰电流随着胆固醇浓度的增加而增加，范围从0.01μg/ mL到5000μg/ mL，检出限为0.001μg/ mL（S / N = 3）。此外，超灵敏胆固醇生物传感器显示出更高的特异性，可接受的重现性和出色的胆固醇检测回收率。