Injectable pH- and Temperature-Responsive Hydrogels for Scaffold Applications in Tissue Engineering

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Injectable hydrogels are promising for minimally invasive tissue engineering scaffolds.
• Existing hydrogels often lack a combination of desired properties like biocompatibility, responsiveness, and mechanical strength.

Purpose of the Study:

• To develop a novel injectable hydrogel scaffold by integrating carboxymethyl cellulose (CMC), poly(ethylene glycol) (PEG), and poly(ε-caprolactone) (PCL).
• To evaluate the physicochemical properties and cytocompatibility of the synthesized CMC-g-(mPEG-b-PCL) hydrogel for potential applications in bone and cartilage tissue engineering.

Main Methods:

• Synthesized a pH- and temperature-responsive CMC grafted with methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) [CMC-g-(mPEG-b-PCL)] via ring-opening polymerization and EDC/NHS coupling.
• Characterized the hydrogel structure using 1H NMR and FTIR spectroscopy.
• Evaluated sol-gel transition, rheological properties, porous structure (SEM), and cytocompatibility (MTT, live/dead assays) with L929 fibroblasts and MG63 cells.

Main Results:

• Successfully synthesized and characterized the CMC-g-(mPEG-b-PCL) graft copolymer.
• The 32 wt% hydrogel exhibited favorable sol-gel transition, injectable properties under physiological conditions, and storage moduli comparable to cartilage tissue.
• SEM revealed an interconnected porous structure, and cell viability assays confirmed excellent cytocompatibility with preserved cell morphology.

Conclusions:

• The synthesized CMC-g-(mPEG-b-PCL) hydrogel possesses desirable injectable, mechanical, and structural properties.
• The hydrogel demonstrates significant potential as a biocompatible scaffold for bone and cartilage tissue engineering applications.