Functional paradigm evolution in microneedle materials: design strategies, performance trade-offs, and translational challenges.

INTRODUCTION: Microneedles (MNs) have emerged as a versatile platform for transdermal delivery, enabling minimally invasive administration of small molecules and biologics. As their performance is fundamentally determined by material properties, continuous innovation in MN materials has been central to the evolution of the field. AREAS COVERED: Relevant literature published from 2020 to 2026 is surveyed using Web of Science and PubMed. This review analyzes MN materials using a functional paradigm framework covering structural carriers, controlled-release carriers, intelligent integrated carriers, and emerging all-drug glassy systems. It compares representative materials by design rationale, advantages, limitations, and trade-offs among drug loading, release control, and biocompatibility, and highlights recent advances together with major challenges to clinical translation. EXPERT OPINION: Current progress suggests that MN material design is shifting from proof-of-concept innovation toward translation-oriented optimization. Increasing functionality alone is unlikely to ensure clinical impact unless it is accompanied by reproducibility, manufacturability, safety, and application-specific performance. Future advances will likely depend on simplified high-performance material systems, more predictable responsive release, and drug-specific designs that better balance loading capacity, release precision, and biocompatibility.