Nucleic acid-functionalized metal-organic framework for ultrasensitive immobilization-free photoelectrochemical biosensing

• Published in: Biosensors & bioelectronics 2021-02, Vol.173, p.112832-112832, Article 112832
• Main Authors: Liu, Xiaojuan, Zhao, Yuecan, Li, Feng
• Format: Article
• Language: English
• Subjects: Aptamer; Biosensing Techniques; Carcinoembryonic antigen detection; DNA; Electrochemical Techniques; Exonuclease-assisted recycling amplification; Limit of Detection; Metal-Organic Frameworks; Nucleic acid-functionalized metal-organic frameworks; Nucleic Acids; Photoelectrochemical biosensors
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2020.112832

This work established an immobilization-free photoelectrochemical (PEC) biosensor for ultrasensitive determination of carcinoembryonic antigen (CEA) based on the DNA-functionalized metal-organic frameworks (MOFs) and T7 exonuclease-aided recycling amplification. In this proposal, MOFs were served as nanocarriers for efficient encapsulation of electron donors, while an ingeniously designed hairpin probe (HP) employed as the recognition element. The recognition of CEA by its aptamer sequence in HP triggered the conformational change and the T7 exonuclease-aided recycling amplification, which opened the pore of MOFs to release a large number of electron donors, producing a significantly increased photocurrent. Benefitting from the high loading ability of MOFs and the excellent amplification efficiency of the T7 exonuclease-assisted recycling process, the proposed biosensor is capable of ultrasensitive and highly selective determination of CEA with a detection limit down to 0.36 fg mL-1 and a wide linear range from 1.0 fg mL-1 to 10 ng mL-1. Moreover, the proposed biosensor can also apply to measure CEA in spiked serum samples, indicating that this PEC biosensor holds excellent potential for application in bioanalysis and early disease diagnosis. •An immobilization-free PEC biosensor was constructed for CEA assay.•It is relied on target recognition-induced release of the electron donors from MOFs.•T7 exonuclease-aided recycling amplification was used to improve the sensitivity.•The biosensor shows good performance for CEA with low LOD and wide linear range.•The biosensor exhibits excellent practicability for CEA assay in human serum samples.