Biomimetic Materials for Engineering Stem Cells and Tissues - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 330

group on the polymer and the protein for attachment [31]. In an attempt
to mimic the adhesive nature of mussel pads, Yang et al. developed dopa-
mine-coated polystyrene (PS) or poly(lactic-co-glycolic acid) (PLGA) sub-
strates that could be used to adhere growth factors and peptides suitable
for neural stem cell culture [32]. They showed that such biomimetically
modifi ed substrates could be used for therapeutic applications of human
neural stem cells. Schematic of such a biomimetic surface modifi cation is
shown in Figure 14.3. Liu et al. have shown that the surface of poly l-lactic
acid (PLLA) nanofi ber scaffold could be modifi ed with gelatin [33]. The
nanofi ber scaffold is immersed in solvent along with gelatin. The pores
in the scaffold swell in the solvent and these sites are occupied by gela-
tin. When the PLLA scaffold whose surface is modifi ed with gelatin is
immersed in nonsolvent, the pores solidify resulting in entrapment of
gelatin. In a radical approach to make the surface of metal implants bio-
mimetic, Ravichandran et al. modifi ed the surface of titanium disks using
PLGA or PLGA/collagen nanofi bers coated with nano-hydroxyapatite
(n-HA) as in Figure 14.4 [34]. The surface modifi cation promoted the
adhesion, proliferation, migration, orientation, differentiation of hMSC on
the scaffold resulting in the biomineralization of the PLGA collagen n-HA
scaffold. Their results proved that biomimetic surface modifi cation of Ti

Dopamine Polydopamine (PD)

HO

HO OH

[1] Oxidation
[2] Polymerization

NH 2

HO

(Tris-HCl, oH 8.5)

Substrates (PS, PLGA)

Substrates (PS, PLGA)

Polydopamine coating

Neurotrophic growth factors- NGF, GDNF
Adhesion peptides - C(K)GG YIGSTR
C(K)GG RGD

H OH

OH

N

OH

s OH

Neural stem cells (NSCs)

Neural stem cell manipulation
(Proliferation & Differentiation)

Figure 14.3 Schematic illustration of the polydopamine mediated immobilization
of bioactive molecules (ECM-derived adhesion peptides and neurotrophic
growth factors). Reprinted with permission from ref. [32]. Copyright (2012)
Elsevier [32].