Antimicrobial　lock　solutions　are　important　for　prevention　of　microbial　colonization　and　infection　of　long-term　central　venous　catheters.　We　investigated　the　efficacy　and　safety　of　a　novel　antibiotic-free　lock　solution　formed　from　gas　plasma-activated　disinfectant　(PAD).　Using　a　luminal　biofilm　model,　viable　cells　of　methicillin-resistant　Staphylococcus　aureus,　Staphylococcus　epidermidis,　Pseudomonas　aeruginosa,　and　Candida　albicans　in　mature　biofilms　were　reduced　by　6　to　8　orders　of　magnitude　with　a　PAD　lock　for　60　min.　Subsequent　24-h　incubation　of　PAD-treated　samples　resulted　in　no　detectable　regrowth　of　viable　bacteria　or　fungi.　As　a　comparison,　the　use　of　a　minocycline-EDTA-ethanol　lock　solution　for　60　min　led　to　regrowth　of　bacteria　and　fungi,　up　to　10(7)　to　10(9)　CFU/ml,　in　24　h.　The　PAD　lock　solution　had　minimal　impact　on　human　umbilical　vein　endothelial　cell　viability,　whereas　the　minocycline-EDTA-ethanol　solution　elicited　cell　death　in　nearly　half　of　human　endothelial　cells.　Additionally,　PAD　treatment　caused　little　topological　change　to　catheter　materials.　In　conclusion,　PAD　represents　a　novel　antibiotic-free,　noncytotoxic　lock　solution　that　elicits　rapid　and　broad-spectrum　eradication　of　biofilm-laden　microbes　and　shows　promise　for　the　prevention　and　treatment　of　intravascular　catheter　infections.