Smart Microneedles in Biomedical Engineering: Harnessing Stimuli-Responsive Polymers for Novel Applications

This review aims to provide a comprehensive analysis of recent advancements in smart microneedles (MNs) within the biomedical field, focusing on the integration of stimuli-responsive polymers for enhanced therapeutic and diagnostic applications. Conventional drug delivery and diagnostic methods are known to face limitations in precision, safety, and patient compliance, which can be addressed by the innovative features of smart MNs. Through the use of various stimuli-responsive polymers, these MNs have been designed to react to environmental or physiological cues, allowing for on-demand drug release, biomarker sensing, and localized therapeutic interventions. Fundamental materials used in the fabrication of these MNs, including metals, polymers, and composite hydrogels, are reviewed, and different categories of stimuli-responsiveness, such as photo, electro, thermal, mechanical, and biochemical, are explored. Application-specific designs of MNs in areas such as drug delivery, cancer therapy, diabetes management, and skin disease treatments are also examined. Through this discussion, it is highlighted that smart MNs are poised to play a significant role in advancing personalized and noninvasive medical treatments.