NANOPARTICLE-EMBEDDED MICRONEEDLES FOR ENHANCED TRANSDERMAL DELIVERY: ADVANCES AND APPLICATIONS

Abstract

Transdermal drug delivery (TDD) provides a non-invasive alternative to oral and injectable administration, avoiding gastrointestinal degradation and first-pass metabolism. Traditional TDD systems are limited to small, lipophilic drugs and are prone to skin irritation and low bioavailability. Although microneedles (MNs) have several advantages, they also suffer from limited drug-loading capacity, fast drug diffusion, and mechanical fragility. Recent developments combine nanoparticles with microneedles (NEMNs), improving drug stability, bioavailability, and controlled release. The types of MNs (solid, coated, hollow, dissolving, and hydrogel) and considerations regarding materials (silicon, metals, polymers) are presented alongside nanoparticles to enhance therapeutic outcomes. Advancements in manufacturing methods, such as 3D printing and micromolding, have facilitated the controlled deposition of nanoparticles and enabled scalable fabrication. Stimuli-induced NEMNs triggered by pH, glucose, light, and magnetic fields have applications in site-specific drug release for diabetes management, cancer treatment, wound healing, and the treatment of inflammatory ailments. Combining nanomaterials with biodegradable polymers enhances their strength and compatibility with living organisms. Although improvements have been made, nanoparticle stability, scalability, regulatory compliance, and long-term safety remain significant concerns. To encourage clinical translation, future directions will focus on AI-based closed-loop systems, biomaterials that can perform multiple functions, and eco-friendly manufacturing processes. Overcoming these barriers, NEMNs have the potential to serve as patient-centric treatments for both chronic and acute conditions, thereby closing the gap between nanotechnology and minimally invasive therapeutics.