Cobalt-ferrocene MOF-based colorimetric biosensing platform for naked-eye detection of human papillomavirus

Human papillomavirus (HPV) screening is an important tool for preventing cervical cancer. Nowadays, fluorescence-detection-based polymerase chain reaction (PCR) technology dominates the HPV screening. However, it suffers from the high costs of fluorescence detectors and probes, which increase detection costs and thus limit the accessibility of HPV screening. Since the concentration of inorganic pyrophosphate ions (PPi) is directly correlated with PCR amplification, the PCR results can be monitored by detecting PPi in the reaction system through a colorimetric reaction. Herein, a cobalt-ferrocene metal-organic framework (Co-Fc MOF)-based colorimetric biosensing platform, which correlated the PCR results with PPi concentration, was constructed for colorimetric detection of HPV16 with the naked eye. Petaloid Co-Fc MOF with exceptional peroxidase (POD)-like activity played a key role in ensuring a high PPi detection sensitivity. Simulation calculation and electron spin resonance results indicated that PPi inhibited the catalytic activity of Co-Fc MOF after being adsorbed on the iron atom of ferrocene. Besides, Co-Fc MOF-based colorimetric biosensing platform showed a high selectivity and accuracy towards PPi without the interference from deoxynucleotide triphosphates (dNTPs) and inorganic salts. Further clinical sample investigation demonstrated that the Co-Fc MOF-based colorimetric biosensing platform could accurately distinguish HPV16-positive and HPV16-negative samples after PCR amplification with the naked eye. The Co-Fc MOF-based colorimetric biosensing platform offers an affordable, convenient, and accurate method for widespread HPV screening and cervical cancer prevention.