Figure 2. Biofilm formation
process. Conditioning film is formed upon protein adsorption. Bacteria
adhere and proliferate on the surface to produce extracellular polymeric
substances (EPS).
There is a high demand of medical device and implants especially for
blood contacting devices as well as orthopedic and dental implants.
Here, we focused on how surface engineering techniques on
blood-contacting devices and hard tissue implants improve their
biocontact performance. Current surface modifications to optimize the
antithrombogenicity of biomaterials mainly include physiochemical
treatments such as surface patterning, plasma treatment and surface
coating especially with heparin, and biofunctionalization that relies on
incorporating bioactive agents. Surface engineering of biomaterials for
hard tissue applications typically focusing on promoting implant-tissue
integration and enhancing the corrosion and wear resistance.
Stem cell-based strategies offers a great potential to tissue
engineering and regenerative medicine owing to their self-renewal
ability and multipotency to differentiate into multiple linages.
Normally, stem cells are isolated from their original microenvironment
and processed through in vitro expansion prior to seeding on
scaffolds for engineered tissue production. Notably, the substrate in
which the stem cells are cultured is required to encourage their
proliferation and expansion while maintain their multipotency.
Subsequently, the large population of stem cells is favored for
producing engineered tissue through desired differentiation. Therefore,
deliberate selection of the biomaterials and proper surface
modifications are critical to stem cells regulation.
Commonly used surface engineering methods are summarized in Table 1.
Physicochemical methods alters surface characteristics by physical
texturing and/or chemical reactions including acid etching/oxidation,
grafting of functional groups, surface coating by deposition and
ionizing irradiation treatments and surface patterning by
lithography[1]. Biological methods are mainly
based on biomolecules immobilization either by physical adsorption or
covalent bonding. Not all surface engineering techniques are applicable
and favorable to all biocontact scenarios. Therefore, this review will
be application targeted that recent advances in surface modifications to
address associated problems in optimizing different interactions between
biomaterial and living matter are focused.
Table 1. Summary of common surface
engineering techniques used for biomaterials.