Photoelectrochemical aptasensor based on PTCDA/TiO2 efficient sensitization effect for sensitive protein analysis

Herein, a photoelectrochemical (PEC) aptasensor for sensitive detection of C-reactive protein (CRP) was designed based on the efficient sensitization effect of 3,4,9,10-Perylene tetracarboxylic dianhydride (PTCDA) towards titanium dioxide (TiO2). Initially, TiO2 and PTCDA were continuously incubated on electrode surface to produce a strong PEC signal owing to the PTCDA/TiO2 sensitization structure. Subsequently, electrodeposition of gold nanoparticles (dep Au) was performed to connect with the incubated CRP aptamer (S1) via Au-N bonds. After that, 1-hexanethiol (HT) was added on the surface of the modified electrode to block the non-specific adsorption sites. Eventually, with the addition of CRP, the PEC signal decreased significantly because the CRP-S1 complexes generated by the specific recognition of CRP and S1 resulted in high steric hindrance effect and inhibited electron transfer. Under optimal conditions, the proposed PEC aptasensor was applied successfully for sensitive CRP detection with a wide linear range from 10 pg/mL to 10 & mu;g/mL and a low detection limit of 3.33 pg/mL. Moreover, the designed PEC aptasensor based on PTCDA/TiO2 sensitized structure might be a versatile tool that provides a powerful alternative to traditional proteins, ions and RNAs detection methods by changing the corresponding recognition sequences.