Poly-L-Lysine is widely used in biomedical research and cell culture applications due to its ability to enhance cell adhesion. It is commonly applied as a coating on glass slides or surfaces to improve the attachment of cells, particularly in microscopy and tissue culture studies. This property makes it valuable for experiments involving cell growth, differentiation, and analysis. Additionally, it is utilized in the preparation of diagnostic assays, such as ELISA, where it helps immobilize biomolecules on solid substrates. In the field of drug delivery, Poly-L-Lysine is employed as a component in nanoparticles or polymers to improve the binding and uptake of therapeutic agents by cells. Its cationic nature also makes it useful in gene delivery systems, where it aids in the condensation and protection of DNA during transfection processes.