Ti₃C₂ MXene-based nanozyme as coreaction accelerator for enhancing electrochemiluminescence of glucose biosensing

Delamination of the exfoliated multilayer MXenes with electro-catalysts, not only leads to increasing surface area for high electrochemiluminescent (ECL) signal tracer loading but also provides highly sensitive achievements in a coreaction accelerator manner. To this end, herein, we used bromophenol blue (BPB)-delaminated multilayer Ti₃C₂ MXene as both a coreaction accelerator to promote the electrochemiluminescent (ECL) reaction rate of luminol (LUM) and the co-reactant H₂O₂ and a substrate for retaining high loading of glucose oxidase (GOx)-conjugated polyethylene imine (PEI) along with luminophore species into more open structure of Ti₃C₂ MXene for sensitive detection of glucose. In the presence of glucose, in situ generating H₂O₂ product through a GOx-catalyzed process could produce abundant ^•OH radicals via the peroxidase-like activity of the BPB@Ti₃C₂ in the LUM ECL reaction. Moreover, decreasing the distance between the high-content LUM into the BPB@Ti₃C₂ and the generated ^•OH, minimizes the decomposition of highly active ^•OH, providing a superb ECL signal. Last, the proximity of incorporated GOx into the delaminated Ti₃C₂ MXene near the electrode allows efficient electron transfer between the electrode and enzyme. The integration of such amplifying effects endowed high sensitivity and excellent selectivity for glucose with a low limit of detection of 0.02 μM in the wide range of 0.01 μM-40,000 μM, enabling the feasibility of the glucose analysis in human serum samples. Overall, the enhanced ECL based on the BPB@Ti₃C₂ opens a new horizon to develop highly sensitive MXene-based ECL toward the field of biosensors.