Carabelli Alessandro M, Isgró Marco, Sanni Olutoba, Figueredo Grazziela P, Winkler David A, Burroughs Laurence, Blok Andrew J, Dubern Jean-Frédéric, Pappalardo Francesco, Hook Andrew L, Williams Paul, Alexander Morgan R
Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, U.K.
School of Computer Science, University of Nottingham, Nottingham NG8 1BB, U.K.
ACS Appl Bio Mater. 2020 Dec 21;3(12):8471-8480. doi: 10.1021/acsabm.0c00849. Epub 2020 Nov 6.
Bacterial biofilms exhibit up to 1000 times greater resistance to antibiotic or host immune clearance than planktonic cells. produces retractable type IV pili (T4P) that facilitate twitching motility on surfaces. The deployment of pili is one of the first responses of bacteria to surface interactions and because of their ability to contribute to cell surface adhesion and biofilm formation, this has relevance to medical device-associated infections. While polymer chemistry is known to influence biofilm development, its impact on twitching motility is not understood. Here, we combine a polymer microarray format with time-lapse automated microscopy to simultaneously assess twitching motility on 30 different methacrylate/acrylate polymers over 60 min post inoculation using a high-throughput system. During this critical initial period where the decision to form a biofilm is thought to occur, similar numbers of bacterial cells accumulate on each polymer. Twitching motility is observed on all polymers irrespective of their chemistry and physical surface properties, in contrast to the differential biofilm formation noted after 24 h of incubation. However, on the microarray polymers, cells twitch at significantly different speeds, ranging from 5 to ∼13 nm/s, associated with crawling or walking and are distinguishable from the different cell surface tilt angles observed. Chemometric analysis using partial least-squares (PLS) regression identifies correlations between surface chemistry, as measured by time-of-flight secondary ion mass spectrometry (ToF-SIMS), and both biofilm formation and single-cell twitching speed. The relationships between surface chemistry and these two responses are different for each process. There is no correlation between polymer surface stiffness and roughness as determined by atomic force measurement (AFM), or water contact angle (WCA), and twitching speed or biofilm formation. This reinforces the dominant and distinct contributions of material surface chemistry to twitching speed and biofilm formation.
细菌生物膜对抗生素或宿主免疫清除的抵抗力比浮游细胞高1000倍。 会产生可收缩的IV型菌毛（T4P），促进在表面上的颤动运动。菌毛的展开是细菌对表面相互作用的首批反应之一，并且由于它们有助于细胞表面粘附和生物膜形成的能力，这与医疗器械相关感染有关。虽然已知聚合物化学会影响生物膜的形成，但其对颤动运动的影响尚不清楚。在这里，我们将聚合物微阵列形式与延时自动显微镜相结合，使用高通量系统在接种后60分钟内同时评估30种不同甲基丙烯酸酯/丙烯酸酯聚合物上的颤动运动。在这个被认为会做出形成生物膜决定的关键初始阶段，每种聚合物上积累的细菌细胞数量相似。与孵育24小时后观察到的生物膜形成差异相反，在所有聚合物上均观察到颤动运动，无论其化学性质和物理表面性质如何。然而，在微阵列聚合物上，细胞以明显不同的速度颤动，范围从5到约13纳米/秒，与爬行或行走有关，并且可以从观察到的不同细胞表面倾斜角度区分出来。使用偏最小二乘（PLS）回归的化学计量分析确定了通过飞行时间二次离子质谱（ToF-SIMS）测量的表面化学与生物膜形成和单细胞颤动速度之间的相关性。表面化学与这两种反应之间的关系在每个过程中都是不同的。通过原子力测量（AFM）或水接触角（WCA）确定的聚合物表面硬度和粗糙度与颤动速度或生物膜形成之间没有相关性。这强化了材料表面化学对颤动速度和生物膜形成的主要且独特的贡献。
