Understanding bacterial surface and adhesion properties and the implications for Pickering stabilization of colloidal structures

Gram-positive bacteria can be considered as structural building blocks adhering to interfaces and taking part in the formation of colloidal structures depending on their surface chemistry and properties. The chemical composition and spatial conformation of the Gram-positive bacterial cell wall, particularly of the species Lactobacillus, determine their surface properties and adhesion behaviors. One application of bacterial adhesion can be the stabilization of colloidal structures via a Pickering mechanism. The natural composition of Gram-positive bacteria renders abundant hydrophilic surface polysaccharides due to the presence of a thick peptidoglycan layer, making it unfavorable for their adsorption at interfaces, however, this property provides sufficient binding sites to allow surface modification. Understanding the fundamental physicochemical forces governing bacterial adhesion helps to reveal their potential applications as Pickering particles. The novelty of this work is that this review summarizes the major non-specific interactions occurring between bacteria approaching a surface, the commonalities and differences of bacteria to Pickering particles, and how a series of simple and advanced colloidal structures can be stabilized by natural and surface-modified bacteria.