New visual immunoassay for prostate-specific antigen using near-infrared exciting CuxS nanocrystals and imaging on smartphone
A photothermal immune-imaging assay was innovatively designed for visual detection of cancer biomarker by using near-infrared (NIR) exciting CuxS nanocrystals and imaging on smartphone-based portable infrared thermal imager. CuxS nanocrystal as a promising photothermal material with high photothermal conversion efficiency combining the results of Rolling circle amplification (RCA) by immune assay was introduced in the detection system. The formation of CuxS nanocrystal concatemer converted NIR optical energy into thermal energy which was output on the smartphone in the form of temperature and thermal contrast imaging. The thermal contrast imaging showed on smartphone could achieve semiquantitative analysis according to series of color changes from blue to red. Moreover, the temperature response with the increasing target concentration could be quantitative analyzed. This photothermal immune-imaging assay scheme provided a promising platform for portable detection of cancer biomarker.