Mechanical interactions between bacterial cells and extracellular polymeric substance are essential in determining biofilm assembly and disassembly as well the mechanical characteristics of biofilms. However, the physics of these mechanical interactions in different cell culture conditions are poorly understood. We created typical artificial biofilm consisting of planktonic bacteria and hydrogel, in the absence of metabolic or regulatory effect. We have demonstrated that the cell culture medium can significantly affect the mechanical interactions between bacterial cells and hydrogels. The stiffness of the bacteria-hydrogel artificial biofilm cannot be simply attributed by the summation of the contribution from the bacteria and hydrogel based on the mathematical models and computational models. We have revealed that the tryptone component of Luria-Bertani broth medium plays an important role in stiffening effect of bacteria-hydrogel construct. Such significant stiffening effect can be explained by the following mechanism: the presence of tryptone in cell culture medium may enable the bacteria itself to crosslink the hydrogel polymer chains. Our findings have also demonstrated the synergy of modelling and innovative experiments which would potentially impact the biofilm control strategies.

中文翻译：

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细菌和水凝胶之间的机械相互作用。

细菌细胞和细胞外聚合物之间的机械相互作用对于确定生物膜的组装和拆卸以及生物膜的机械特性至关重要。然而，人们对在不同细胞培养条件下这些机械相互作用的物理学了解甚少。在没有代谢或调节作用的情况下，我们创建了由浮游细菌和水凝胶组成的典型人工生物膜。我们已经证明，细胞培养基可以显着影响细菌细胞和水凝胶之间的机械相互作用。细菌-水凝胶人工生物膜的刚度不能简单地归因于基于数学模型和计算模型的细菌和水凝胶贡献的总和。我们已经发现，Luria-Bertani肉汤培养基中的胰蛋白component成分在细菌-水凝胶构建体的增强作用中起着重要作用。这种显着的增强作用可以通过以下机理来解释：细胞培养基中胰蛋白tone的存在可以使细菌自身交联水凝胶聚合物链。我们的发现还证明了建模和创新实验的协同作用，这将潜在地影响生物膜控制策略。