Poly-L-histidine is widely used in biomedical research and applications due to its unique properties. It is often employed as a component in drug delivery systems, where it helps in the efficient transport of therapeutic agents across cell membranes. Its ability to buffer pH changes makes it valuable in gene therapy, particularly in the delivery of nucleic acids, where it can protect DNA or RNA from degradation. Additionally, poly-L-histidine is utilized in the development of biosensors and diagnostic tools, as it can bind to metal ions, enhancing detection sensitivity. In tissue engineering, it is incorporated into scaffolds to promote cell adhesion and growth, aiding in the regeneration of damaged tissues. Its biocompatibility and functional versatility make it a crucial material in advancing medical technologies.