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.