Bakterilerin polimerik yüzeylerle etkileşimi

Abstract

Abstract ABSTRACT The aim of this study is to investigate interactions of bacteria with biomaterials, and to decrease the bacterial adhesion by modification of biomatenal surface with plasma polymerization. Six gram positive and four gram negative bacteria strains were isolated from clinical samples, and identified by several techniques. Hydrophobicities of these bacteria were defined by using contact angles and the percentage of bacteria passed to organic phase (i.e., /j-xylene). Zeta potentials and surface charges of the bacteria were determined as electrostatic properties. Several biodegradable or nondegradable mono or multifiament sutures (i.e., Vicryl, Dexon, Cromic catgut, PDS and PP), a polyvinylchloride (PVC) catheter and a silicone (Si) balloon catheter were evaluated as biomaterials. Surfaces of these biomaterials were modified by plasma polymerization in which dimethylaminoethyl methacrylate (DMAEMA) and acrylic acid (AAc) were used as the active monomers. Plasma modifications were performed for different plasma exposure times (5, 10 and 15 min) and discharge powers (5 and 10 watt). Contact angles of both original and plasma modified biomaterial were obtained by a captive bubble technique. The contact angles of gram positive bacteria were in the range of 48-69°, which means that they are moderately hydrophobic (except the CNS-2 strain which is relatively hydrophilic). While the contact angles of gram negative bacteria were in the range of 43.5-55°, which means that they are moderately hydrophilic. Hydrophobicities of both groups of bacteria defined with the percentage of bacteria passed to /»-xylene phase were obtained in parallel to those defined by contact angles. All bacteria accept CNS-2 and CPS-1 exhibited negative surface charge. Zeta potentials of the gram positive and gram negative bacteria were found in a wide range from +1 8.60 to -650 mV. Only two of the strains, i.e., CNS-2 and CPS-1, exhibited positive zeta potential values which were +18.6 and + 17.5, respectively. For bacterial adhesion studies the optimal concentration of bacteria was obtained as lxl09(cfu/cm2). Bacterial adhesion was found as a function of incubation time. The strains adhesion of some bacteria decreased with respect to time, while for some others increased.Abstract Bacterial adhesion which obtained in dynamic incubation media was higher than those observed in static experimental set up. The maximum bacterial adhesion was observed for Vicryl sutures. In the plasma modification of these sutures, in which DMAEMA and AAc plasma were used, the optimal (corresponding the minimum bacterial adhesion) plasma exposure time and discharge power were obtained at 5 min and 10 watt, respectively. Very similar adhesion behaviours were observed for all biomaterials tested in this study (i.e., Vicryl sutures, PVC catheters and Silicone balloon catheter). The highest gram positive bacterial adhesions were observed for Silicone balloon catheter, while much lower values were found for Vicryl sutures. Among the gram positive bacteria used in this study the highest adhesions were observed for the CNS-1 and S.yug-1 strains. In most of the cases (but not all) there were correlations between the extend of adhesion and surface properties of both the bacteria and the biomaterial. Hydrophobic gram positive bacteria have adhered more to the hydrophobic biomaterial surfaces. While, just opposite, more hydrophilic gram negative bacteria have been found to adhere to more hydrophilic biomaterial surfaces. The main result in respect to the main aim of this study it was shown that in most of the cases, especially for the CNS-1, CNS-2, CPS-1, E.coli-1, E.coli-2 and P.aeru-1 strains plasma modification significantly improved the antibacterial character (means less bacterial adhesion) of all biomaterials tested. The AAc plasma was more succesful than the DMAEMA plasma in this respect.

Abstract ABSTRACT The aim of this study is to investigate interactions of bacteria with biomaterials, and to decrease the bacterial adhesion by modification of biomatenal surface with plasma polymerization. Six gram positive and four gram negative bacteria strains were isolated from clinical samples, and identified by several techniques. Hydrophobicities of these bacteria were defined by using contact angles and the percentage of bacteria passed to organic phase (i.e., /j-xylene). Zeta potentials and surface charges of the bacteria were determined as electrostatic properties. Several biodegradable or nondegradable mono or multifiament sutures (i.e., Vicryl, Dexon, Cromic catgut, PDS and PP), a polyvinylchloride (PVC) catheter and a silicone (Si) balloon catheter were evaluated as biomaterials. Surfaces of these biomaterials were modified by plasma polymerization in which dimethylaminoethyl methacrylate (DMAEMA) and acrylic acid (AAc) were used as the active monomers. Plasma modifications were performed for different plasma exposure times (5, 10 and 15 min) and discharge powers (5 and 10 watt). Contact angles of both original and plasma modified biomaterial were obtained by a captive bubble technique. The contact angles of gram positive bacteria were in the range of 48-69°, which means that they are moderately hydrophobic (except the CNS-2 strain which is relatively hydrophilic). While the contact angles of gram negative bacteria were in the range of 43.5-55°, which means that they are moderately hydrophilic. Hydrophobicities of both groups of bacteria defined with the percentage of bacteria passed to /»-xylene phase were obtained in parallel to those defined by contact angles. All bacteria accept CNS-2 and CPS-1 exhibited negative surface charge. Zeta potentials of the gram positive and gram negative bacteria were found in a wide range from +1 8.60 to -650 mV. Only two of the strains, i.e., CNS-2 and CPS-1, exhibited positive zeta potential values which were +18.6 and + 17.5, respectively. For bacterial adhesion studies the optimal concentration of bacteria was obtained as lxl09(cfu/cm2). Bacterial adhesion was found as a function of incubation time. The strains adhesion of some bacteria decreased with respect to time, while for some others increased.Abstract Bacterial adhesion which obtained in dynamic incubation media was higher than those observed in static experimental set up. The maximum bacterial adhesion was observed for Vicryl sutures. In the plasma modification of these sutures, in which DMAEMA and AAc plasma were used, the optimal (corresponding the minimum bacterial adhesion) plasma exposure time and discharge power were obtained at 5 min and 10 watt, respectively. Very similar adhesion behaviours were observed for all biomaterials tested in this study (i.e., Vicryl sutures, PVC catheters and Silicone balloon catheter). The highest gram positive bacterial adhesions were observed for Silicone balloon catheter, while much lower values were found for Vicryl sutures. Among the gram positive bacteria used in this study the highest adhesions were observed for the CNS-1 and S.yug-1 strains. In most of the cases (but not all) there were correlations between the extend of adhesion and surface properties of both the bacteria and the biomaterial. Hydrophobic gram positive bacteria have adhered more to the hydrophobic biomaterial surfaces. While, just opposite, more hydrophilic gram negative bacteria have been found to adhere to more hydrophilic biomaterial surfaces. The main result in respect to the main aim of this study it was shown that in most of the cases, especially for the CNS-1, CNS-2, CPS-1, E.coli-1, E.coli-2 and P.aeru-1 strains plasma modification significantly improved the antibacterial character (means less bacterial adhesion) of all biomaterials tested. The AAc plasma was more succesful than the DMAEMA plasma in this respect.