Temperature Platform Constructed Using a Cu2O–Cu31S16 Photothermal Conversion System for the Simple Quantitative Analysis of Tumor Markers

The quantitative detection of carcinoembryonic antigen (CEA) indicators is a critical step in the early clinical diagnosis of cancer because CEA is closely related to the development of cancer. However, the most commonly used methods for CEA detection mainly involve comparing or measuring the color depth of colored substance solutions, which is not highly accurate, particularly when a second colored substance is present in the solution to be evaluated. Herein, we rationalized the design of a photothermal probe based on calcium carbonate (CaCO3) as a protective shell (Cu2O@CaCO3) for cuprous oxide (Cu2O) nanoparticles to prevent Cu2O oxidation and hyaluronic acid (HA) to confer material biocompatibility (Cu2O@CaCO3@HA). Cu2O can be specifically activated by hydrogen sulfide (H2S), transformed into Cu31S16 nanoparticles and display significant photothermal properties that can be visualized for bioanalysis by simply recording the temperature signal with a thermal imager. In addition, the presence of redox pairs can provide further electrochemically assisted validation of the temperature identification system. Given the portable, economical, and sensitive biosensing, we anticipate that future activatable nanoprobes may be used to assist in early cancer diagnosis and screening.