Hydrogel Microneedles for Perioperative Applications: Drug Delivery, Biosensing, and Theranostic Translation

Hydrogel microneedles provide access across the skin barrier for drug delivery and interstitial-fluid sampling. Their perioperative use depends on whether that access remains reliable during skin preparation, surgical positioning, and changes in tissue perfusion. This narrative review examines how material design affects delivered dose, measurement accuracy, and clinical feasibility. Human sampling studies establish feasibility for selected measurements; most therapeutic and integrated sensing applications remain at the preclinical stage or have been investigated in other clinical settings. The review distinguishes these findings from evidence in surgical patients. Particular attention is given to insertion and adhesion on disinfected or compromised skin, the relationship between interstitial and plasma measurements, and drug exposure after delivery is interrupted. Short-duration superficial procedures and observational drug or wound-adjacent monitoring offer focused questions for initial studies with standard care maintained. Progress toward treatment requires validation of the complete product, including sterilization, batch consistency, shelf life, and safeguards against uncontrolled release. Clinical studies should report failed applications and adverse events alongside patient outcomes. Autonomous anesthetic administration remains a development goal whose safety cannot be inferred from separate demonstrations of sensing and drug release.