Disclosed herein are methods of making pure chalcogenide (e.g., selenium, tellurium, or selenium/tellurium) nanoparticles by irradiating chalcogenide pellets by nano-second laser ablation using chitosan as a capping agent to form chitosan chalcogenide nanoparticles (CS-CgNPs). CS-CgNPs and methods of using such particles are also disclosed herein, such as antimicrobials and antimicrobial coatings effective against biofilms.
