Strategies to Prevent Bacterial Adhesion on Biomaterials - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 171

8 dyn/cm 2 showed more adhesion
of S. epidermidis with higher hydrophobicity. This effect on adhesion with
different hydrophobicity was found to be less prominent when the shear
stresses increase. The bacterial surface hydrophobicity was found to be
ineffective for adhesion at the shear stress of more than 15 dyn/cm 2 [59].
Bacterial surface charge: Cells acquire charge on their surface. Some
bacterial species contain positive charge and some contain negatively

The shear stresses in the range of 0 −

−
charged surfaces because different types of bacteria have different surface
chemical structure. Cell surface charge may alter according to the age of
bacteria. Cells may alter their surface charge in growth medium corre-
sponding to pH and charged ions of the culture medium [9]. Cell surface
charges play a dominant role in adhesion on biomaterial surface [60].

7.2.4.1.6 Tissue Proteins (Serum)
Bacterial adhesion vastly depends on serum proteins. The effect of some
important proteins, like albumin, fi brinogen and thrombin, is discussed
below. Generally, serum proteins are attached to the cell surface through
the specifi c receptor

ligand interactions [9].
Albumin: In most of the studies, polymer, ceramic and metallic bio-
material surfaces coated with albumin are reported to inhibit bacterial
adhesion on surface. The cause of this inhibitory effect of albumin was
suggested to enhance hydrophilicity of albumin

−

coated surfaces [9].
Fibrinogen: It is one of the important factors for the adhesion of bac-
teria. Staphylococci adhesion is found to be higher on fi brinogen absorbed
surfaces [61].
Platelets : In a study, it was found that the contact

−

activated plate-
lets mediate bacterial adhesion to the polyethylene substrate instead of
absorbed plasma proteins, because the adhesive coeffi cient to the protein

−

−
adsorbed polyethylene surface was notably lower as a minimum one order
of magnitude than to the platelets [62]. In another study, the adhesion of
S. aureus was found to be around 30

− fold higher for platelets compared to

albumin − PMMA [63].

7.2.5 Synthetic Biomaterials with Microbial

Resistance Property

Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) is one of the extensively used hard
tissue replacement material because of compositional similarity with
natural bone, good biocompatibility and its ability to facilitate strong
biological bond with bone [64]. On the other hand, poor mechani-
cal properties of monolithic HA like low fracture toughness ( 1 MPa

m −1/2 ) do not enable it to endure the normal operating loads of bones
or joints [65]. Importantly, hydroxyapatite (HA) lacks antibacterial
property. Implant

<

− associated infections are serious and widespread