PHYSICOCHEMICAL ASPECTS OF DEPOSITION OF STREPTOCOCCUS-THERMOPHILUS-B TO HYDROPHOBIC AND HYDROPHILIC SUBSTRATA IN A PARALLEL-PLATE FLOW CHAMBER
PHYSICOCHEMICAL ASPECTS OF DEPOSITION OF STREPTOCOCCUS-THERMOPHILUS-B TO HYDROPHOBIC AND HYDROPHILIC SUBSTRATA IN A PARALLEL-PLATE FLOW CHAMBER
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DOI：
10.1006/jcis.1994.1177
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发表时间：
1994-05-01
影响因子：
9.9
通讯作者：
BUSSCHER, HJ
中科院分区：
文献类型：
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作者：
MEINDERS, JM;VANDERMEI, HC;BUSSCHER, HJ
我们测量了在pH为2和7的40 mm磷酸二氢钾溶液中，嗜热链球菌B从氟乙烯丙烯(FEP)、聚甲基丙烯酸甲酯(PMMA)和玻璃(即一系列日益亲水的表面)上的初始沉积速率、每颗粒的阻塞面积以及与停留时间相关的解吸。初始沉积速率与pH或捕收器表面疏水性变化不大，可能是因为沉淀对质量传输的高度贡献。然而，即使在通过平均顶板和底板数据来消除沉积影响之后，仍发现沉积效率超过90%。沉积作用对局地分布函数g(x，y)的影响也很明显，表现为上游和下游近邻聚集程度较高。在pH为7时，三种捕收剂表面的阻挡面积约为10个颗粒截面积，在pH为2时，FEP的阻挡面积约为200个颗粒截面积，并且似乎受静电相互作用和疏水性的相互作用的控制，其方式类似于固定状态下附着的细胞数量。初始和最终的解吸速率系数在pH 7时比在pH 2时低，而在pH 7时的松弛时间大约是在pH 2时的两倍，这表明在pH 7时从可逆到不可逆的黏附的转变比在pH 2时更快。为了消除碰撞的影响，通过黏附细胞在无细胞流动悬浮液中的解吸来估计结合强度。假设势垒为平方势垒，我们发现每个晶胞的键强度为16-17kT，这与基于界面热力学的估计值非常吻合。总之，这里使用的具有实时原位图像分析的平行平板流室提供了关于沉积过程的丰富信息，这些信息可能有助于解开控制微生物在固体表面沉积的复杂机制。(C)1994年学术出版社。
We measured the initial deposition rate onto, the blocked area per particle of, and the residence-time-dependent desorption of Streptococcus thermophilus B from fluoroethylene propylene (FEP), poly(methylmethacrylate) (PMMA), and glass, i.e., a series of increasingly hydrophilic surfaces, from a 40 mM potassium phosphate solution at pH 2 and 7. The initial deposition rates did not vary much with pH or collector surface hydrophobicity, presumably due to a high contribution of sedimentation to mass transport. However, even after elimination of sedimentation effects by averaging of top and bottom plate data, deposition efficiencies of over 90% were found. The effects of sedimentation were also obvious in the local distribution function g(x, y), showing a high degree of both upstream and downstream near-neighbor collection. The blocked areas ranged from about 10 particle cross-sections for all three collector surfaces at pH 7 to about 200 particle cross-sections for FEP at pH 2 and appeared governed by an interplay of electrostatic interactions and hydrophobicity, in a manner similar to the number of cells adhering in the stationary state. The initial and final desorption rate coefficients were lower at pH 7 than at pH 2, whereas the relaxation times at pH 7 were about two times larger than those at pH 2, indicating a faster transition from reversible to irreversible adhesion at pH 7 than at pH 2. Bond strengths were estimated from the desorption of adhering cells when exposed to a cell-free flowing suspension in order to eliminate the effects of collisions. Assuming a square potential well, we found bond strengths of 16-17 kT per cell, which corresponded remarkably well to estimates based on interfacial thermodynamics. In summary, the parallel plate flow chamber with real-time in situ image analysis, as used here, offers a wealth of information regarding the deposition process that might help to unravel the complex mechanisms governing microbial deposition onto solid surfaces. (C) 1994 Academic Press, Inc.