Graphene-Based Polymeric Microneedles for Biomedical Applications: A Comprehensive Review

Transdermal drug delivery presents a promising noninvasive approach, bypassing first-pass metabolism and gastrointestinal degradation. However, the stratum corneum (SC) barrier limits drug absorption, necessitating the development of effective delivery systems. Microneedles, particularly polymer-based ones, offer a solution by penetrating the SC while avoiding critical nerves and capillaries. These microneedles are biodegradable, nontoxic, and easily manufacturable, making them a highly attractive platform for transdermal drug delivery. However, their clinical application remains limited due to suboptimal therapeutic efficacy and slow drug release rates. Recent advancements have introduced the incorporation of nanodrugs, such as nanoparticles and encapsulated drugs, into microneedles to enhance drug delivery efficiency. Among the materials explored, graphene and its derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), have garnered significant attention. Their exceptional mechanical strength, electrical conductivity, and antibacterial properties not only improve the mechanical performance of microneedles but also enhance drug release rates and biocompatibility. This review synthesizes the current state of microneedle technologies, focusing on the materials, fabrication techniques, and performance challenges. It particularly examines the potential of graphene-based microneedles, comparing them to traditional polymer-based microneedles in terms of drug release efficiency and stability. The review highlights key challenges, such as scalability, biocompatibility, and fabrication complexity, and suggests future research directions to address these issues. The incorporation of graphene quantum dots (GQDs) is identified as a promising avenue for improving drug release profiles, stability, and real-time tracking of drug diffusion. Finally, the review outlines emerging applications, including smart drug delivery systems, biosensing, and real-time monitoring, urging further exploration to unlock the full potential of graphene-enhanced microneedles in clinical settings.