posted on 2013-06-10, 00:00authored byHaitao Cui, Jun Shao, Yu Wang, Peibiao Zhang, Xuesi Chen, Yen Wei
Injectable
hydrogels have served as biomimic scaffolds that provide
a three-dimensional (3D) structure for tissue engineering or carriers
for cell encapsulation in the biomedical field. In this study, the
injectable electroactive hydrogels (IEHs) were prepared by introducing
electrical properties into the injectable materials. Carboxyl-capped
tetraaniline (CTA) as functional group was coupled with enantiomeric
polylactide–poly(ethylene glycol)–polylactide (PLA-PEG-PLA),
and the electroactive hydrogels were obtained by mixing the enantiomeric
copolymers of CTA-PLLA-PEG-PLLA-CTA and CTA-PDLA-PEG-PDLA-CTA aqueous
solutions. ultraviolet–visible spectroscopy (UV–vis)
and cyclic voltammetry (CV) of the complex solution showed good electroactive
properties. The gelation mechanism and intermolecular multi-interactions
such as stereocomplextion, hydrogen bonding, and π–π
stacking were studied by Fourier transform infrared spectroscopy (FT-IR),
UV–vis, and wide-angle X-ray diffraction (WAXD). Gelation properties
of the complexes were also studied by rheometer. The encapsulated
cells remained highly viable in the gel matrices, suggesting that
the hydrogels have excellent cytocompatibility. After subcutaneous
injection, the gels were formed in situ in the subcutaneous layer,
and hematoxylin–eosin (H&E) staining suggested acceptable
biocompatibility of our materials in vivo. Moreover, these injectable
materials, when treated with pulsed electrical stimuli, were shown
to be functionally active and to accelerate the proliferation of encapsulated
fibroblasts, cardiomyocytes, and osteoblasts. Hence, the IEHs possessing
these excellent properties would be potentially used as in vivo materials
for tissue engineering scaffold.