Near-Infrared Light-Responsive Composite Microneedles for On-Demand Transdermal Drug Delivery

This study presents near-infrared (NIR) light-responsive polymer-nanostitcture composite microneedles used for on-demand trans dermal chug delivery. Silica-coated lanthanum hexaboride (LaB6@SiO2) nanostructures were incorporated into polycaprolactone microneedles, serving as: an NIR absorber. When the microneedles were irradiated with NIR light, light-to-heat transduction mediated by the LaB6@SiO2 nanostructures caused the microneedle melting at 50 degrees C. This increased the mobility of the polymer chains,, enabling drug release from the matrix. Drug release from the microneedles was evaluated: for four laser on/off cycles. In each cycle, the samples were irradiated until the temperature reached 50 degrees C for 3 min (laser on); the laser was then turned off for 30 min (laser off). The results showed that light-induced phase transition in the polymer triggered drug release from the Melted microneedles. A stepwise drug-release behavior was observed after Multiple cycles of NIR light exposure. No notable drug leakage was found in the off state. This,NIR-light-triggerable device exhibits excellent reproducibility, low off-state leakage, and noninvasive triggerability and, thus, represents an 'advance' in transdermal delivery technology.