2D carbon network arranged into high-order 3D nanotube arrays on a flexible microelectrode: integration into electrochemical microbiosensor devices for cancer detection

In this work, we develop a new type of mesoporous 2D N, B, and P codoped carbon network (NBP-CNW) arranged into high-order 3D nanotube arrays (NTAs), which are wrapped onto a flexible carbon fiber microelectrode, and this microelectrode is employed as a high-performance carbon-based nanocatalyst for electrochemical biosensing. The NBP-CNW-NTAs synthesized by a facile, controllable, ecofriendly and sustainable template strategy using ionic liquids as precursors possess a high structural stability, large surface area, abundant active sites, and effective charge transport pathways, which dramatically improve their electrocatalytic activity and durability in the redox reaction of cancer biomarker H2O2. Benefiting from these unique structural merits, superb electrochemical activity and good biocompatibility, the NBP-CNW-NTAs-modified microelectrode demonstrates excellent sensing performance toward H2O2 and is embedded in a homemade microfluidic electrochemical biosensor chip for the real-time tracking of H2O2 secreted from different live cancer cells with or without radiotherapy treatment, which provides a new strategy for distinguishing the types of cancer cells and evaluating the radiotherapeutic efficacy of cancer cells. Furthermore, the functional microelectrode is integrated into an implantable probe for the in situ detection of surgically resected human specimens to distinguish cancer tissues from normal tissues. These will be of vital significance for cancer diagnoses and therapy in clinical practice.