Title : A novel responsive microneedle platform for reliable drug and vaccine delivery
Abstract:
Introduction: Driven by rising demand for minimally invasive healthcare, ageing populations and at-home treatment options, microneedles (MNs) offer a compelling alternative to injections, particularly for vaccines and chronic therapies. However, commercial adoption has been hindered by usability challenges, specifically, the absence of clear visual indicators for correct patch application and removal. Addressing this gap is critical to unlocking their full potential in clinical and consumer markets, enhancing patient confidence, therapeutic accuracy and regulatory approval. To address this, we have developed an innovative, responsive microneedle platform featuring a built-in colour-change feedback mechanism[1-2].
Results: The final optimised MNs demonstrated well-defined geometries, consistent microneedle heights, and precisely controlled interspacing, attributed to the uniform micro-mould design. These features enabled effective insertion into Parafilm®M models, with height reduction upon compression remaining below 20%.
The MNs integrated with visual feedback indicators showed a rapid colour transition from yellow to green within 3 minutes post-insertion on rat skin, triggered by microneedle hydration from interstitial fluid. This was followed by a shift to purple within 2 hours, indicating complete microneedle dissolution and confirming successful drug delivery. In vivo pharmacokinetic studies in Sprague Dawley rats revealed that the PLA-silica MN achieved a peak plasma concentration (Cmax) of 1864 ± 480 ng/mL at 0.5 hours, while the PVP-baseplate MN reached a Cmax of 973 ± 200 ng/mL at 1 hour. Both systems demonstrated good biocompatibility with no signs of irritation or adverse reactions .
Conclusion: This study presents a responsive microneedle platform for painless, reliable transdermal delivery of enfuvirtide. The PLA–silica system provides a colour-change feedback mechanism for accurate dosing and easy removal while maintaining safety and biocompatibility. With tunable release and a user-friendly application, it offers a promising, scalable solution for next-generation peptide and vaccine delivery.
