NANOMATERIALS FOR IMPROVED ORTHOPEDIC AND BONE TISSUE ENGINEERING APPLICATIONS - Advanced Biomaterials: Fundamentals, Processing, and Applications - page 220

(a) (b)

100 µm 100 µm

Figure 7.8. Scanning electron microscopy images of chemically treated and conventional
untreated PLGA surfaces. (A) Conventional PLGA (feature dimensions ∼ 10-15 μ m) and (B)
chemically treated nanostructured PLGA (feature dimensions ∼ 50-100 nm). Scale bar is 100 μ m.
Adapted from [95].

depending on the copolymer ratio. Recently, this copolymer and its homopoly-
mer derivatives, PLA and PGA, have received substantial attention for skeletal
repair and regeneration. Various techniques—such as particulate leaching, textile
technologies or three-dimensional (3D) printing techniques—have successfully
created 3D porous matrices from PLGA and its derivatives [89-92]. For instance,
with the simplicity of the polymer casting and phase separation processes, a
robust nanofi brous poly(l-lactic acid) (PLLA) scaffold can be prepared [93].
These nanofi brous scaffolds have a collagen-like 3D structure, high porosity
and a suitable surface structure for osteoblast attachment, proliferation, and
differentiation.
In addition, several studies have shown that nanostructured PLGA (Figure
7.8) which is prepared by chemical etching procedures can promote vascular
endothelial and smooth muscle cell adhesion compared to the conventional
PLGA [94 - 95] .
Further investigation demonstrated that nanostructured PLGA can adsorb
signifi cantly more vitronectin and fi bronectin from serum compared to conven-
tional PLGA, just as the aforementioned nano ceramics and metals do [93].
This increase in protein adsorption may help explain enhanced osteoblast adhe-
sion observed on PLGA with nano-surface roughness. In addition, signifi cantly
increased chondrocyte functions—adhesion, proliferation and matrix synthesis—
have been observed on NaOH-treated nanostructured PLGA [97]. Furthermore,
improved osteoblast functions have also been observed on nanophase titania/
PLGA composites which make them promising as bone tissue engineering scaf-
fold materials [98]. At the same time, it was found that fi broblast density de-
creased on nanophase PLGA, polyurethane and polycaprolactone which may
inhibit the formation of a fi brous tissue capsule [99]. Obviously, because nano-
structured PLGA has excellent biocompatibility properties (above that of