This study explores the engineering of hybrid nanotube (CNT) microwires to enhance the performance of biofuel cells (BFCs) for miniaturized biomedical devices. The researchers found that CNT microwires, which are highly porous and have a large specific surface area, significantly improve electron transfer and mass transport compared to conventional carbon fiber (CF) electrodes. Under physiological conditions, the maximum power density of a miniature membraneless glucose/oxygen BFC using CNT microwires was four times higher than that of a CF BFC. The improved performance is attributed to the enhanced porosity, efficient enzyme-enzyme and enzyme-electrode connections, and reduced overpotentials for glucose electrooxidation and oxygen electroreduction. The study demonstrates the potential of CNT microwires in developing high-power, miniaturized BFCs for applications such as continuous glucose monitoring in diabetes management.This study explores the engineering of hybrid nanotube (CNT) microwires to enhance the performance of biofuel cells (BFCs) for miniaturized biomedical devices. The researchers found that CNT microwires, which are highly porous and have a large specific surface area, significantly improve electron transfer and mass transport compared to conventional carbon fiber (CF) electrodes. Under physiological conditions, the maximum power density of a miniature membraneless glucose/oxygen BFC using CNT microwires was four times higher than that of a CF BFC. The improved performance is attributed to the enhanced porosity, efficient enzyme-enzyme and enzyme-electrode connections, and reduced overpotentials for glucose electrooxidation and oxygen electroreduction. The study demonstrates the potential of CNT microwires in developing high-power, miniaturized BFCs for applications such as continuous glucose monitoring in diabetes management.