Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54 124 Thessaloniki, Greece.
Department of Civil Engineering, Aristotle University of Thessaloniki, University Box 10, 54 124 Thessaloniki, Greece.
Langmuir. 2023 Jun 27;39(25):8589-8602. doi: 10.1021/acs.langmuir.3c00179. Epub 2023 Apr 20.
Microbial adhesion and spreading on surfaces are crucial aspects in environmental and industrial settings being also the early stage of complex surface-attached microbial communities known as biofilms. In this work, -laden droplets on hydrophilic substrates (glass coupons) are allowed to partially evaporate before running wetting measurements, to study the effect of evaporation on their interfacial behavior during spillover or splashing. Forced wetting is investigated by imposing controlled centrifugal forces, using a novel rotatory device (). At a defined evaporation time, results for the critical tangential force required for the inception of sliding are presented. Microbe-laden droplets exhibit different wetting/spreading properties as a function of the imposed evaporation times. It is found that evaporation is slowed down in bacterial droplets with respect to nutrient medium ones. After sufficient drying times, bacteria accumulate at droplet edges, affecting the droplet shape and thus depinning during forced wetting tests. Droplet rear part does not pin during the rotation test, while only the front part advances and spreads along the force direction. Quantitative results obtained from the well-known Furmidge's equation reveal that force for sliding inception increases as evaporation time increases. This study can be of support for control of biofilm contamination and removal and possible design of antimicrobial/antibiofouling surfaces.
微生物在表面的黏附和铺展是环境和工业领域中至关重要的方面，也是被称为生物膜的复杂表面附着微生物群落的早期阶段。在这项工作中，在进行润湿测量之前，让负载微生物的液滴在亲水基底（玻璃片）上部分蒸发，以研究蒸发对液滴在溢出或飞溅过程中界面行为的影响。通过使用新型旋转装置（）施加受控的离心力来研究强制润湿。在定义的蒸发时间后，给出了用于滑动起始的临界切向力的结果。负载微生物的液滴表现出不同的润湿/铺展特性，这取决于施加的蒸发时间。结果发现，与营养介质相比，细菌液滴中的蒸发速度较慢。经过足够的干燥时间后，细菌在液滴边缘积聚，影响液滴形状，并在强制润湿测试中解钉。在旋转测试过程中，液滴的后部不会解钉，而只有前部沿力的方向前进并扩展。从著名的 Furmidge 方程获得的定量结果表明，随着蒸发时间的增加，滑动起始的力也会增加。这项研究可以为控制生物膜污染和去除以及可能设计抗菌/抗生物污损表面提供支持。
