Highly sensitive photoelectrochemical detection of cancer biomarkers based on CdS/Ni-CAT-1 nanorod arrays Z-scheme heterojunction with spherical nucleic acids-templated copper nanoclusters as signal amplification

Ultrasensitive and accurate detection of low-abundance cancer markers is critical for early diagnosis of cancer. To date, developing high-performance photoelectrode and efficient signal amplification strategies remain core challenges for photoelectrochemical bioanalysis. Herein, a CdS/conductive metal-organic frameworks nickel-catecholates nanorod (Ni-CAT-1 NR) arrays Z-scheme heterojunction was developed as a high-performance photoelectrode for split-type photoelectrochemical aptasensing of carcinoembryonic antigen (CEA, as a model cancer marker) with advanced spherical nucleic acids-templated copper nanoclusters (SNAs-Cu NCs) as signal amplification. The Ni-CAT-1 NR arrays not only match with the energy band of CdS, but also act as a direct pathway for electron transfer to the electrode surface, reducing the photogenerated charges recombination rate. In the presence of CEA, aptamer-modified magnetic beads and aptamer-anchored SNAs-Cu NCs reacted with the target to form a sandwich-like structure and plenty of Cu2+ released from SNAs-Cu NCs by acidolysis could react with CdS/Ni-CAT-1 NR arrays to generate trapping site, reducing the photocurrent. Under optimal conditions, the prepared aptasensor showed a wide linear range from 0.01 pg mL−1-1.0 ng mL−1, a low detection limit of 0.003 pg mL−1, and excellent stability and accuracy, demonstrating a promising platform for biomarkers detection.