Microneedle biosensors: from molecular recognition to intelligent diagnostics

Accurate acquisition of disease-associated molecular information is increasingly essential for disease diagnosis and health management. However, conventional biomarker detection is typically invasive and highly dependent on laboratory analysis, limiting its applicability to continuous, real-time, and personalized health monitoring. Microneedle (MN) biosensors can access disease-related molecular information in interstitial fluid (ISF) in a minimally invasive manner, providing a promising approach for dynamic molecular monitoring. Recent advances in micro/nano manufacturing technologies, materials science, biosensing strategies, and digital technologies have significantly expanded the capabilities of MN biosensors, enabling the development of intelligent biosensing platforms. This review systematically summarizes the key technologies underpinning intelligent MN biosensors, focusing on ISF access, molecular recognition, signal transduction, and artificial intelligence-assisted data processing. Moreover, the applications of MN biosensors in disease diagnosis and monitoring are discussed, with representative studies covering metabolic disorder management, immune monitoring, cancer diagnosis and monitoring, and neurological disorder monitoring. Finally, current challenges and future opportunities are outlined, including long-term monitoring, biocompatibility, and clinical translation, with the aim of providing guidance for the design and application of next-generation intelligent MN biosensing platforms.