Recent progress of NIR light-controlled microneedles and therapeutic applications: A review study

Transdermal drug delivery presents an appealing alternative to traditional administration methods like oral and injection routes, as it circumvents first-pass metabolism, minimizes pain and infection risks, and enhances patient compliance. Nonetheless, the skin barrier remains a significant obstacle to delivering most medications through the skin. Microneedles (MNs) represent an innovative technology that can address this issue by forming tiny pores in the skin, facilitating the transport of drugs or biomolecules. MNs are manufactured from various materials and come in different designs and classifications. They can also be activated by external stimuli, such as near-infrared (NIR) light, which excels over other light types for this application due to its deeper tissue penetration, allowing for on-demand and precise temporal drug delivery. This review primarily concentrates on NIR light-controlled MNs, which respond to NIR light exposure to release drugs. Here, the fundamental concepts and mechanisms behind NIR light-controlled MNs are introduced, which utilize NIR light-sensitive materials or devices that alter their properties or functions in response to NIR light exposure. Benefits and difficulties associated with NIR light-controlled MNs, such as their extensive penetration capability, low toxicity, and accurate control, are examined. The potential for integrating NIR light-controlled MNs with other therapeutic strategies to boost their efficacy will be investigated. Recent advancements and applications of NIR light-controlled MNs in diverse areas, including diabetes management, cancer therapy, and wound healing, are reviewed. Finally, the future directions for their application will be addressed.