Modification of Polyhydroxyalkanoates (PHAs) - Polyhydroxyalkanoate (PHA) Based Blends, Composites and Nanocomposites - page 158

Table 7.1 Typical PHA physical modification methods.

PHA Modification method Results/application Ref.

PHBHHx Hyaluronan coating Improved hydrophilicity, low

fibroblast L929 cellular growth
1.6 10 5 (4 10 5 ) a cells per ml.
Could be employed in biomaterial
selection and design.

77

d n 2 r 4 n g | 1

PHBHHx PHB blending Improved biocompatibility and

higher fibroblast L929 cellular
growth 1.9 10 5 (1.8 10 4 ) a cells
per cm 2 . Could be employed in
biomaterial selection and design.

81

mcl-PHA Crosslinking by

g-irradiation

Higher cross linked density,
decreased biodegradability.
Increased Young's modulus 129%
(114%), a improved tensile strength
76% (35%). a

82

PHO, PHU PEGMA grafting by

UV irradiation

Reduced blood protein adsorption,
platelet adhesion, and improved
blood compatibility. Potential
application in blood contacting
devices.

83,84

OH - PHB ion implantation Improved bioactivity, wettability.

Suitable for cell culture scaffold.

85

PHBV O 2 plasma treatment Increased hydropilicity, reduces

polymer surface roughness,
resulting in high cell growth and
attachments. A potential scaffold
for retinal pigment epithelium cell
culture.

86

.

PHBV Electrospinning Improved elastic property, increased

wettability. Scaffold for tissue
engineering.

87

a

Numbers in parentheses represent unmodified PHA control values.

environmental degradation and reduced biofouling caused by soil mi-
crobes. 88 In fact, blending the PHA with DCOI was observed to postpone the
onset of weight loss by up to 100 days, about a 10-fold increase in degrad-
ation stability compared to neat PHA film. 88
Previous studies have shown that PHA granule binding protein (PhaP) and
its fusion proteins, such as arginine-glycine-aspartate (RGD) tri-peptide,
have higher cell-binding sequences, which improve cell survival, attach-
ment, motility and proliferation, allowing their usage in specific drug de-
livery devices and cell sorting. 89,90 You et al. 89 compared the biocompatibility
and cell viability of a scaffold made of neat PHBHHx to that of PHBHHx
coated with PHA PhaP fused with RGD (PhaP-RGD). The study showed
that the PhaP-RGD coating led to better homogeneity in cell spreading,
adhesion, proliferation with improved chondrogenic differentiation and
high extracellular matrix production compared with the neat PHBHHx
scaffold.