Strategies to Prevent Bacterial Adhesion on Biomaterials - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 168

death phase which arises because of accretion of waste near the cell, the
dearth of nutrients in the growth medium, and the detrimental environ-
mental conditions which results in the rapid death of cells [7].

7.2.3 Bacterial Adhesion and Biofi lm Formation

The prokaryotic cells also have a tendency to adhere on biomaterial sub-
strate [29]. After adhesion they proliferate to form cell clusters on the
material surface, as shown in Figure 7.9. A mass of bacterial cells along
with their extracellular material (slime) is called biofi lm [38]. Only a lim-
ited number of bacteria can be accumulated in a established biofi lm, other
excess adherent bacterial cells get away from the slime layer and form
new colony on another place of the substrate material [39]. In a study it
was reported that some bacterial strains that do not generate slime are
found comparatively less adherent and therefore less harmful for humans
[32]. Slim layers work as a shield for bacteria viz. protection against phago-
cytosis, antibiotic effects and high fl ow conditions [40]. The immune sys-
tem can easily kill the bacteria that are less susceptible to the adhesion on
surface. Many slime generating bacteria developed antibiotics resistance

after adhering to the biomaterial surface [41]. Prosthetic infection occurs
when a bacterial population defeats the local host defense system [42].

−

Prokaryotic
cells

Adhesion Proliferation Microcolony Mature

biofilm

Program
mobilization to
prokaryotic cells

Mature
biofilm

Physical
detachment

Figure 7.9 Schematic illustration of various stages in bacterium biofi lm
formation (adapted from ref. [43]).