All-in-one coupling of 3D hybridized nanocarbon microelectrode for portable monitoring of doxycycline hyclate

The simultaneous balance of electrode materials and electrode structures can energize the development of innovative electrochemical sensors. In this work, a 3D nanocarbon layer of hybrid heteroatoms and metal atoms (CN/Fe) with excellent electrical properties and abundant active sites was self-constructed on the surface of a quartz-based nanofiber by high-temperature pyrolysis. Further, the nanofiber tip was selected as the sensing region to develop an electrochemical sensing platform with high sensitivity, miniaturization, and portability. A common broad-spectrum antibiotic (Doxycycline hyclate, DOX) was used as a model to evaluate the designed miniaturized sensing platform, and the stability, reproducibility, and applicability of the microsensor were verified in a variety of real samples, including algal solution, milk, human serum, and cell culture media. The results show that the proposed sensing platform has a detection limit as low as 82 nM in aqueous environments. Furthermore, it is further shown that coupling the design of electrode materials and electrode structures facilitates the development of electrochemical sensors with more practical applications. This concept will open up new avenues for the development of electrochemical sensors that meet many application scenarios.