The infection risk of biomaterial implants is determined by an interplay of bacterial adhesion and surface growth of the adhering organisms. In this study, we compared initial adhesion and surface growth of Pseudomonas aeruginosa AK1 (zeta potential −7 mV) on negatively charged (PMMA/MAA, zeta potential −18 mV) and positively charged (PMMA/TMAEMA-Cl, zeta-potential +12 mV) methacrylate copolymers in situ in a parallel plate flow chamber. Initial adhesion was measured using phosphate-buffered saline and subsequent surface growth of the adhering bacteria using nutrient broth as growth medium. Initial adhesion was twice as fast on the positively charged methacrylate than on the negatively charged copolymer. Surface growth, however, was absent on the positively charged copolymer, while on the negatively charged methacrylate the number of bacteria increased exponentially during surface growth with a generation time of 32 min. From the results of this study it can be concluded that positively charged biomaterial surfaces might show reduced risks of biomaterials-centred infections, despite being more adhesive.

Initial adhesion and surface growth of Pseudomonas aeruginosa on negatively and positively charged poly(methacrylates)

Biofilms are the aggregates of the bacterial colonies which are found to be the friends and foes to the mankind. Biofilms of bacteria can be employed in not only removal of organic waste but can also can be used in treatment of hexavalent chromium containing waste, an element which is found to be carcinogenic, mutagenic and irritative in nature. The organism forming biofilm is isolated from tannery effluent and is quantitatively and qualitatively analysed by using tube assay and microtiter plate assay. The isolate was identified by using 16srRNA technology with the help of barcode institute Aurangabad it is identified as Bacillus vietnamiensis .Bacillus vietnamiensis culture was able to reduce almost 100% of 500mg/lt of hexavalent chromium at 6 pH and tempratureof 35°C under normal areobic conditions.Optimisation experiments proved temperature 35°C and pH 6 is more favourabl e for bacterial growth and as well as reductionprocess.The bacteria is found to be more potent as it is obtained from the indigenous source and found to be very efficient in reduction of hexavalent chromium.. Keywords— EPS-exopolysaccharide, PBSphosphate buffered saline, QSquorum sensing, TSBTrypticase soya broth, AHL-acylhomoserine lactones, AI auto inducers.

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Nikhita H Ingalagi

Papers

Chromium reduction using bacterial biofilms