Busalmen J P, de Sanchez S R, Schiffrin D J
INTEMA, Facultad de Ingenieria, Universidad Nacional de Mar del Plata, 7600 Mar del Plata, Argentina.
Appl Environ Microbiol. 1998 Oct;64(10):3690-7. doi: 10.1128/AEM.64.10.3690-3697.1998.
Ellipsometric measurements were used to monitor the formation of a bacterial cell film on polarized metal surfaces (Al-brass and Ti). Under cathodic polarization bacterial attachment was measured from changes in the ellipsometric angles. These were fitted to an effective medium model for a nonabsorbing bacterial film with an effective refractive index (nf) of 1.38 and a thickness (df) of 160 +/- 10 nm. From the optical measurements a surface coverage of 17% was estimated, in agreement with direct microscopic observations. The influence of bacteria on the formation of oxide films was monitored by ellipsometry following the film growth in situ. A strong inhibition of metal oxide film formation was observed, which was assigned to the decrease in oxygen concentration due to the presence of bacteria. It is shown that the irreversible adhesion of bacteria to the surface can be monitored ellipsometrically. Electrophoretic mobility is proposed as one of the factors determining bacterial attachment. The high sensitivity of ellipsometry and its usefulness for the determination of growth of interfacial bacterial films is demonstrated.
椭偏测量用于监测极化金属表面（铝黄铜和钛）上细菌细胞薄膜的形成。在阴极极化条件下，通过椭偏角的变化测量细菌附着情况。这些数据被拟合到一个有效介质模型中，该模型用于非吸收性细菌薄膜，其有效折射率（nf）为1.38，厚度（df）为160±10纳米。通过光学测量估计表面覆盖率为17%，这与直接显微镜观察结果一致。通过原位监测薄膜生长，利用椭偏测量法监测细菌对氧化膜形成的影响。观察到金属氧化膜形成受到强烈抑制，这归因于细菌的存在导致氧气浓度降低。结果表明，细菌在表面的不可逆粘附可以通过椭偏测量法进行监测。电泳迁移率被认为是决定细菌附着的因素之一。证明了椭偏测量的高灵敏度及其在确定界面细菌薄膜生长方面的实用性。
