MXene-derived Ti3C2 quantum dots-based ratiometric fluorescence probe for ascorbic acid and acid phosphatase determination

As a burgeoning zero-dimensional nanomaterial, MXene quantum dots which are derived from two-dimensional transition-metal carbides have attracted a lot of interest lately. The transformation of two-dimensional MXene into zero-dimensional structures of a few nanometers enables these recently discovered materials to possess an exceptional quantum size effect and remarkable photoluminescence characteristics. Hence, we synthesized N doped Ti3C2 MXene quantum dots (N-Ti3C2 MQDs) exhibiting bright blue fluorescence through small-molecule amine-assisted solvothermal strategy. In this work, we constructed a novel ratiometric fluorescence biosensor for the determination of ascorbic acid (AA) and acid phosphatase (ACP) based on the excellent optical performance of N-Ti3C2 MQDs and combined o-phenylenediamine (OPD). This ratiometric strategy was established based on the inner filter effect between N-Ti3C2 MQDs and the oxide of OPD. Sensitive fluorometric analyses of AA and ACP were achieved successfully in the respective ranges of 2-240 mu M and 0.15-3.75 U/L with respective limits of detection down to 0.82 mu M and 0.02 U/L. Moreover, the response time of this fluorescence sensor for AA and ACP determination was less than 1.5 h. The intraday and interday relative standard deviations for AA and ACP assay were all below 8.3 %, suggesting the good reproducibility of this sensor. In addition, the profuse color changed under UV light with analytes concentrations increased and exhibited great potential for visual detection and on -site application. The proposed method was further utilized to screen of potential ACP inhibitors, indicating that this probe has great potential in clinical practice.