Emerging electroactive bio-microneedles for innovative minimally invasive theranostic applications

Microneedles (MNs) have emerged as a transformative minimally invasive platform in biomedicine, enabling painless transdermal drug delivery and diagnostic applications. However, conventional MNs face critical limitations, including functional singularity, inefficient drug utilization, and immune complications. Recent advancements in electroactive bio-microneedles (Ebio-MNs) offer innovative solutions by synergizing electrical responsiveness with biological adaptability, facilitating intelligent closed-loop theranostic integration. This review comprehensively explains the core mechanism of the electroactivity strategy and the development and current status of Ebio-MN intelligent diagnosis and treatment, while systematically analyzing progress in Ebio-MN classifications, functional base materials (e.g., conductive polymers, metallic/carbon composites, ionic conductors), and precision manufacturing technologies (e.g., lithography, 3D printing, MEMS). Special emphasis is placed on bioinspired structural designs that enhance tissue compliance and electrochemical interfaces. In the therapeutic domain, Ebio-MNs demonstrate multifunctional advantages in stimuli-responsive drug release, real-time biomarker tracking, and electrostimulation-enhanced wound healing through mechanisms such as electrical modulation. Case studies highlight their biomedical applications in diabetes management, chronic wound repair, and tumor electrochemotherapy, showcasing integrated devices capable of simultaneous monitoring and intervention. By bridging MN innovation with intelligent system design, this review outlines a roadmap for next-generation personalized theranostic platforms, offering critical insights into electrically driven biointerfaces and closed-loop healthcare solutions.