The hospital environment harbors bacteria that may cause health care-associated infections. Microorganisms, such as multiresistant bacteria, can spread around the patient's inanimate environment. Some recently introduced biodecontamination approaches in hospitals have significant limitations due to the toxic nature of the gases and the length of time required for aeration. This study evaluated thein vitrouse of cold air plasma as an efficient alternative to traditional methods of biodecontamination of hospital surfaces. Cultures of methicillin-resistantStaphylococcus aureus(MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum-β-lactamase (ESBL)-producingEscherichia coli, andAcinetobacter baumanniiwere applied to different materials similar to those found in the hospital environment. Artificially contaminated sections of marmoleum, mattress, polypropylene, powder-coated mild steel, and stainless steel were then exposed to a cold air pressure plasma single jet for 30 s, 60 s, and 90 s, operating at approximately 25 W and 12 liters/min flow rate. Direct plasma exposure successfully reduced the bacterial load by log 3 for MRSA, log 2.7 for VRE, log 2 for ESBL-producingE. coli, and log 1.7 forA. baumannii. The present report confirms the efficient antibacterial activity of a cold air plasma single-jet plume on nosocomial bacterially contaminated surfaces over a short period of time and highlights its potential for routine biodecontamination in the clinical environment.

Point-of-care (POC) diagnostics implementing microfluidic technology on single use disposable plastic chips has potential applications in personalized medicine, clinical diagnostics and global health. However, the challenges in commercializing POC devices must be addressed. Immobilization of biomolecules to plastic chips through appropriate surface functionalization is a key issue for the fabrication of new generation biomedical diagnostic devices. The most important requirements for a practicable surface functionalization process are speed, control and reliability. Plasma-based methods can meet these criteria. A single step, solventless, ecofriendly and high throughput nature of plasma processing makes them highly attractive. Here we demonstrate the efficient surface functionalization of a next-generation biosensor material, a chemically inert cycloolefin polymer (COP). The plasma formation of a surface-bound aminated siloxane network from mixed aminopropyltriethoxysilane and ethylenediamine precursors allowed us to form a well-adherent film with an exceptionally high degree of amine functionalization. We deduce that the siloxane was the critical component for radical insertion into the COP and for building a stable network to support the reactive amine functionalities. We present a full physical and chemical characterization of the films, including a detailed study of their swelling in water, using an array of surface analytical techniques: X-ray photoelectron spectroscopy, X-ray reflectivity, reflection infra-red spectroscopy, atomic force microscopy (AFM) and fluorophore binding reactions. We demonstrate an original approach for qualitatively analyzing the distribution of amine functionalities by counting surface-bound functionalized silica nanoparticles in the AFM. The relative contributions from covalent (specific) and non-covalent (non-specific) reaction chemistry assessed using 3′-fluorescein-labeled ssDNA attachment showed that the non-specific binding could be reduced significantly according to the particular feed gas mixture used to prepare the coating. A reaction mechanism has been proposed for the deposition of amine functionalities on COP plastic and also for enhancing the amine functionalities that affect the non-specific binding significantly.