A slimy, protective community of bacteria that sticks to surfaces—much harder to kill with antibiotics than free-floating bacteria.Biofilms are structured microbial communities embedded in a self-produced extracellular polymeric substance (EPS) matrix attached to surfaces. Biofilm bacteria exhibit 10–1,000× greater antibiotic resistance than planktonic cells due to restricted antibiotic penetration, metabolic dormancy, and persister cell formation. Several antimicrobial peptides (nisin, temporins, pexiganan) demonstrate anti-biofilm activity by disrupting biofilm matrix, penetrating established biofilms, or preventing initial biofilm attachment—advantages over conventional antibiotics.