Discipline: Biological Sciences
Paula Datri - Southern University at New Orleans
Co-Author(s): Paula Datri, Altoneisha Rose, Neyda Chacon, Pamela Marshall, Illya Tietzel, and Christian Clement, Southern University at New Orleans, New Orleans, LA
Biofilms form when any group of microorganisms attach to a surface and secrete extracellular polymeric substances. Biofilms are a public health risk. Furthermore, biofilms on marine equipment, machinery exposed to moisture, air ducts and other mechanical equipment impede or reduce efficiency of these engineered systems. Spacecraft and space equipment are exposed to microbes and microbial contamination of water supply on-board, rendering it unsafe for human travel. Formation of biofilms on the complex and critical systems of a spacecraft like the International Space Station or the proposed future Orion Spacecraft would have the potential to threaten mission success. Therefore, methods to prevent and degrade biofilms are critical and use of nanoparticles is at the forefront of planning of the strategic roadmaps of NASA. The specific nanoparticles Polybead® Polystyrene Red Dyed Microsphere were found to be antibacterial, therefore, it is hypothesized that they can prevent or degrade biofilms. Breakdown of biofilms by nanoparticles is primarily dependent on surface chemistry of nanoparticles. In order to test this hypothesis, overnight bacteria cultures were transferred into fresh medium at a ratio of 1:10 and incubated to rapidly yield new cultures at the log phase. Polystyrene nanoparticles of varying size and surface chemistry were co-incubated with Escherichia coli that can form biofilms and also Bacillus megaterium and B. cereus. Microbial growth was assessed using the Standard Plate Count and Optical Density was also measured. Biofilms were estimated by a Crystal Violet based assay spectrophotometrically at wavelengths of 600 and 700 nm. A rigorously modified Kirby Bauer Disk Diffusion assay with glass microscopic slides inserted into nutrient agar medium to capture forming biofilms in close proximity to nanoparticles diffusion reservoirs allowed detectable interaction which were recorded using photomicrographs. Biofilm formation was also confirmed by a modified Crystal Violet based test tube assay. Results show that nanoparticles negatively impact biofilm formation by reducing its size and distorting the matrix structure. Nanoparticles of different surface chemistry were observed to inhibit the formation of biofilm. Taken together, the negative effects of nanoparticles on biofilm formation appeared to be dose-dependent and the type of bacteria exposed. The mechanism(s) of nanoparticles prevention or degradation of biofilms will be studied.
Funder Acknowledgement(s): The research was supported by NASA CAN NNX13AR32 - subcontracts OSP-14-216821-00E and OSP-14-216821-02E to I. Tietzel /Additional funding by NASA EPSCoR RAP I. Tietzel (Co-PIs: C. Clement; P. Marshall; Y. Zhen; O. Ojo).
Faculty Advisor: Christian Clement,