Injectable In Situ Self-Cross-Linking Hydrogels Based on Poly(l-glutamic acid) and Alginate for Cartilage Tissue Engineering

Abstract

Injectable hydrogels as an important biomaterial class have been widely used in regenerative medicine. A series of injectable poly(l-glutamic acid)/alginate (PLGA/ALG) hydrogels were fabricated by self-cross-linking of hydrazide-modified poly(l-glutamic acid) (PLGA-ADH) and aldehyde-modified alginate (ALG-CHO). Both the degree of PLGA modification and the oxidation degree of ALG-CHO could be adjusted by the amount of activators and sodium periodate, respectively. The effect of the solid content of the hydrogels and oxidation degree of ALG-CHO on the gelation time, equilibrium swelling, mechanical properties, microscopic morphology, and in vitro degradation of the hydrogels was examined. Encapsulation of rabbit chondrocytes within hydrogels showed viability of the entrapped cells and good biocompatibility of the injectable hydrogels. A preliminary study exhibited injectability and rapid in vivo gel formation, as well as mechanical stability, cell ingrowth, and ectopic cartilage formation. The injectable PLGA/ALG hydrogels demonstrated attractive properties for future application in a variety of pharmaceutical delivery and tissue engineering, especially in cartilage tissue engineering.

Intrathecal Delivery of Ketorolac Loaded <i>In Situ</i> Gels for Prolonged Analgesic and Anti-Inflammatory Activity in Vertebral Fracture

“…Apart from being nonmutagenic and non-cytotoxic, biodegradable polymers are metabolized in the body and eliminated by normal physiological pathways [17,18]. Of the various fabrication systems available, in situ gels show potential for local as well as systemic controlled drug delivery systems [19][20][21]. Further, since intrathecal KT (free drug) pre-treatments have been reported to reduce the spinal cord ischemic and VF injuries [22], this study employed in situ gels for intrathecal KT administration due to the disadvantages associated with the administration of free KT (e.g., poor drug stability, reduced half-life, frequent administration and hence reduced patient compliance).…”

Development of an <i>in</i> situ polymeric hydrogel implant of methylprednisolone for spinal injuries

“…This process ultimately results in the formation of a porous polymer matrix, which then slowly releases the drug [20]. In situ gels can be used for local and systemic controlled drug delivery [14,15,[21][22][23]. Here, we describe the development of a polymeric in situ hydrogel of MP for intrathecal delivery to improve neuroprotective and neuroregenerative effects in SCI.…”

Self-Healing Supramolecular Self-Assembled Hydrogels Based on Poly(l-glutamic acid)

“…The representative FTIR spectra of PLGA 1433 -b-PEG 2000 -b-PLGA 1433 , Chol, and (PLGA 1433 -b-PEG 2000 -b-PLGA 1433 )-g-Chol were presented in Figure 2b. For PLGA 1433 -b-PEG 2000 -b-PLGA 1433 , the stretching vibration of C−H bond in PEG 2000could be characterized by the peaks at 2930 and 2850 cm −1 , the peak at 1729 cm −1 was ascribed to the stretching vibration of carbonyl group in PLGA 1433 , and the characteristic absorption peaks at 1630 and 1521 cm −1 were attributed to amide I and amide II groups, respectively 38. For the native Chol, the peaks of C−H bond at 2930 and 2850 cm −1 were attributed to the stretching vibration of C−H bond.…”