Aptamer‐functionalized Ti 3 C 2 ‐MXene Nanosheets with One‐step Potentiometric Detection of Programmed Death‐ligand 1

This communication describes a simple sensitive one‐step potentiometric aptasensing method for quantitative detection of a referenced therapeutic biomarker (programmed death‐ligand 1, PD−L1). The aptasensor is constructed by modifying PD−L1‐specific aptamer on Ti 3 C 2 ‐MXene nanosheets‐functionalized electrode. Introduction of PD−L1 induces the specific reaction between PD−L1 and aptamer, thereby resulting in the change of spatial structures. The surface electric potential of modified electrode is shifted upon addition of PD−L1 proteins before and after the reaction of aptamer with the analyte. Interestingly, potentiometric aptamer with Ti 3 C 2 ‐MXene nanosheets can achieve a higher sensitivity and a lower detection limit toward target PD−L1 relative to aptamer‐modified electrode. Experimental results indicated that the linear range and detection limit of using Ti 3 C 2 ‐MXene nanosheets were 0.01–100 ng mL −1 and 7.8 pg mL −1 PD−L1, respectively. Meanwhile, the specificity, reproducibility, storing stability and accuracy of potentiometric aptasensor are acceptable for the screening of PD−L1 in human serum samples.