Colorimetric Biosensor for Detection of Cancer Biomarker by Au Nanoparticle-Decorated BiSe Nanosheets.

The colorimetric biosensors have attracted intensive interest; however, their relatively low sensitivity limits their applications in clinic detection. Herein, we develop an effective colorimetric biosensor based on highly catalytic active Au nanoparticle-decorated BiSe (Au/BiSe) nanosheets. Au/BiSe nanosheets are facilely synthesized by simply sonicating Au precursor with the as-synthesized BiSe nanosheets in aqueous solution. Because of the low redox potential and typical topological insulating properties, BiSe nanosheets is capable of providing and accumulating electrons on its surface. Such unique properties of BiSe nanosheets contribute to strong synergistic catalytic effects with Au nanoparticles, particularly when Au/BiSe nanosheets are utilized for catalyzing the reduction of 4-nitrophenol (4-NP) by NaBH (K = 386.67 sg). The excellent catalytic activity of Au/BiSe nanosheets can be "switched off" upon treatment of antibody of cancer biomarker such as anticarcinoembryonic antibody (anti-CEA). Addition of the corresponding antigen such as cancer biomarker carcinoembryonic antibody (CEA) can successively help "switch on" the catalytic activity of Au/BiSe nanosheets, where the resuming degree however depends on the antigen concentration. This cancer biomarker depended catalytic behavior therefore allows Au/BiSe nanosheets to be employed as a colorimetric sensor for detection of a particular cancer biomarker, for the reduction of 4-nitrophenol (4-NP) by NaBH itself involves apparent color change. The sensor shows high sensitivity and selectivity for the cancer biomarker, even for a concentration as low as 160 pg/mL for CEA, which fully satisfies the requirement for real clinical applications. The developed colorimetric sensor shows good generality for detection of different types of cancer biomarkers, such as α-fetoprotein (AFP) and prostate-specific antigen (PSA). Furthermore, real clinic sample analyzing result shows that the prepared biosensor is efficient for detection of CEA, providing an alternative method in cancer diagnosis.