A mediator and spatial-resolution induced dual-ratiometric self-powered photoelectrochemical aptasensor for accurate detection of antibiotics

This work reports a dual-ratiometric self-powered photoelectrochemical sensor (SPPS) by the combination of the photocathode with potassium persulfate (K2S2O8) as mediator and the photoanode with spatial-resolution technique. The key point is to utilize the activation and conversion of K2S2O8 as a mediator to generate two power peaks (PMax1 and PMax2) simultaneously. Spatial-resolution technique offers reference signals (PMax3 and PMax4) for two power peaks, respectively. With chloramphenicol (CAP) as model analytes, a dual-ratiometric SPPS was developed with aptamer as recognition unit. Briefly, the specific capture of CAP increased the power peaks gradually to produce sensing signals which is capable of quantifying CAP. The sensor can provide two sets of sensing signals related to the CAP concentration, i.e., PMax1/PMax3 (R = 0.997) and PMax2/PMax4 (R = 0.999) with a detection limit (S/N = 3) of 0.29 pM. Compared with single-signal or single-ratiometric SPPS, the dual-ratiometric SPPS exhibits improved analytical performances, proposing a feasible way to realize self-checking and anti-interference. [Display omitted] •A dual-ratiometric self-powered sensor was proposed for the first time.•The sensor was obtained by coupling K2S2O8 with spatial-resolution technique.•V2C MXene was introduced to improve the sensitivity.•The self-powered sensor showed self-checking and anti-interference capability.•The work offers a strategy for building multiple-ratiometric self-powered sensors.