Label-free homogeneous photoelectrochemical aptasensing of VEGF165 based on DNA-regulated peroxidase-mimetic activity of metal-organic-frameworks

The application of metal-organic frameworks (MOFs) nanozymes in biosensing has been extensively investigated, however, till now there is still no report on photoelectrochemical (PEC) sensing based on enzyme memetic properties of MOFs. To further expand the utilization of MOFs nanozymes in biosensing, we developed a label-free homogenous PEC aptasensor for the detection of VEGF165, an important cancer biomarker, based on the DNA-regulated peroxidase-mimetic activity of Fe-MIL-88, a type of MOFs. In this strategy, the peroxidase-mimetic property of MOFs is integrated with the label-free homogeneous PEC sensing approach, and highly sensitive detection of VEGF165 is obtained with a detection limit down to 33 fg/mL, superior or comparable to the previously reported values. Moreover, this approach displays outstanding specificity, and has been successfully used to detect VEGF165 added in diluted serum samples. As far as we know, it is the first example to employ the peroxidase-like activity of MOFs in PEC biosensing, which may find potential application in bioanalysis and early disease diagnosis.