Redox-controlled fluorescent sensor for highly reactive oxygen species detection and cell imaging based on dihydrolipoic acid functionalized carbon quantum dots

A novel redox-controlled fluorescent sensor for the detection of highly reactive oxygen species (hROS) was developed based on the unique green fluorescence emission of dihydrolipoic acid functionalized carbon quantum dots (DHLA@N-CQDs). Given the excellent redox characteristic between the disulfide bonds (S–S) and thiol (R-SH), the sensor was designed by bonding N-CQDs and DHLA under the action of coupling agents. When hROS was introduced into the sensing system, a large number of S–S gathered between DHLA@N-CQDs can effectively inhibit the fluorescence of probe. In addition, the as-prepared fluorescent sensor can sense hydroxyl radicals (·OH) and hydrogen peroxide (H 2 O 2 ) in different response ranges, which ensures a high selectivity for hROS detection. Furthermore, the sensor system has been successfully utilized to detect the H 2 O 2 in human saliva samples and the fluorescence imaging of ·OH in HeLa cells, exhibiting the feasibility of fluorescent sensors in practical applications.