1. INTRODUCTION
Surface adhesion of bacteria is a common natural phenomenon, and it has become more and more important to study the mechanism of bacterial adhesion to various surfaces in recent decades, because it involves various fields such as biomedicine, industry, ocean and environment[1]. Bacterial adhesion is the first step in their colonization and forming biofilms, which are harmful to human life and industrial production, for example, leading to infection of medical implants, microbial-induced corrosion, pathogen-host cell interactions, periodontitis or dental caries, and contamination of food processing equipment [2-3]. However, microbial adhesion may also be beneficial, for example, in the degradation of environmentally harmful chemicals in soil, treatment of wastewater and waste gases in bioreactors, agricultural applications of rhizobia, and polymer degradation [4-9]. Bacteria achieve free-to-irreversible adhesion through specific interactions with material surfaces, non-specific physicochemical interactions, and surface mechanical induction [10]. Biofilms are formed when bacteria aggregate together to form communities attached to solid surfaces and encapsulated in extracellular polysaccharide matrices. The development process is divided into initial reversible adhesion of bacteria, irreversible adhesion and biofilm growth, and maturation and diffusion phases [11]. This highly complex process is influenced by the bacteria, the adherent material, and the surrounding environment [12]. The formation of bacterial biofilms is one of the mechanisms by which bacteria adapt to their environment, and biofilms rely on their complex internal structure and colony regulation to achieve variability in the external environment and resistance to bacteriostatic drugs[13-14]. In recent decades, biofilm removal has become a global challenge [15], as biofilms, once formed, are difficult to eradicate and can easily cause persistent and widespread bacterial infections with severe consequences. The introduction of atomic force microscopy (AFM) techniques has led to a significant breakthrough in studying bacterial-material surface interactions, enabling the analysis of biofilm or single cell-material surface interactions [16]. AFM can be operated in a liquid environment to study cells’ mechanical properties and the biofilms’ stiffness [17]. Initial adhesion of free bacteria to the material surface is necessary for forming biofilms. The first approach to prevent the formation of biofilms on the material surface is to avoid the initial adhesion of bacteria. In this paper, we review the adhesion mechanism, influencing factors, and testing methods between bacteria and material interfaces to expand researchers’ understanding of adhesion between bacteria and materials and provide directions for solving harmful adhesion of bacteria.