Au and Pt Nanoparticles Grown on Flexible Carbon Fiber Cloth Supports Decorated with Cerium Metal Organic Frameworks for the Real-Time Detection of H₂O₂ in Live Cancer Tissue

Flexible electrochemical biosensors have ignited great interest because they possess the potential to provide continuous and real-time physiological information via dynamic and noninvasive measurements of biochemical markers in biofluids. In this work, a cerium metal–organic framework (Ce-UiO-66- 4,4-biphenyl dicarboxylic acid (BPDC)) was first grown in situ on flexible carbon fiber cloth (CFC) by a one-step hydrothermal method. To further shorten the response time of the biosensor, we used the controllable growth of gold nanoparticles (NPs) and the peroxidase activity of platinum NPs to simultaneously deposit Au and Pt NPs on the surface of Ce-UiO-66-BPDC/CFC, and constructed a supersensitive sensing interface with good electrocatalytic activity. Under the optimal experimental conditions, the detection limit of the enzyme-free H2O2 electrochemical sensor was as low as 89 nM (S/N = 3). Moreover, due to the excellent biocompatibility and flexibility of the Au–Pt/Ce-UiO-66-BPDC/CFC (APCC) bioplatform, lung cancer cells (A549) can be directly cultured on the electrodes to achieve real-time monitoring of the H2O2 released by living cells (2.43 × 10–14 mol cell–1). More importantly, the practical application of APCC fiber microelectrodes explored the real-time monitoring of the release of H2O2 from fresh tissues surgically excised from breast, breast cancer, and lung cancer, which provided an advanced tool for further research on reactive oxygen species biology, such as oxidative stress and subsequent pathology.