Photoelectrochemical aptasensing of lead(II) ion based on the in situ generation of photosensitizer of a self-operating photocathode

•A self-operating photocathode is firstly utilized for photoelectrochemical ion sensing.•Pb2 + induces the in situ formation of hemin sensitized NiO photocathode.•The method is highly sensitive and selective for Pb2 +.

The first example of metal ions sensing based on self-operating photocathode is demonstrated. Lead ion (Pb2 +) induces the allosteric transition of K+-stabilized G-quadruplex intercalated with hemin, which releases hemin to sensitize the p-type NiO electrode, forming the self-operating photocathode. The cathodic photocurrent linearly increases with the concentration of Pb2 + in the range of 20 to 1500 nM with a detection limit of 4.0 nM.

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