Component effect of stem cell-loaded thermosensitive polypeptide hydrogels on cartilage repair

Abstract

Articular cartilage defect has limited self-repair ability due to the lack of blood supply and innervation, which may lead to knee osteoarthritis afterwards. Injectable hydrogels are demonstrated possessing outstanding properties as biomimetic scaffolds in cartilage tissue engineering, while the effect of biophysical properties on the efficacy of cartilage regeneration has not been revealed. Herein, the poly(ethylene glycol)-polypeptide triblock copolymers with different ratios of alanine to phenylalanine were synthesized. The sol-to-gel transition temperature and the critical gelation concentration decreased as the increased amount of phenylalanine unit, resulting in the enlarged pore size and enhanced mechanical strength. These features lead to better regeneration of hyaline-like cartilage with reduced fibrous tissue formation, indicating great potential of thermosensitive polypeptide hydrogels for efficient cartilage repair.

The Use of Peripheral Blood-Derived Stem Cells for Cartilage Repair and Regeneration In Vivo: A Review

“…Since BMS techniques, osteochondral transplantation, and ACI have limitations and shortcomings, such as fibrocartilage regeneration, donor site complications, graft failure, dedifferentiation of seed cells, and two-stage invasive surgical procedures (Fortier et al, 2010;Andriolo et al, 2017;Riboh et al, 2017), MSCs, which are multipotent progenitor cells with an intrinsic potential for multilineage differentiation, self-renewal, low immunogenicity, anti-inflammatory activity, and immunomodulatory effects by suppressing the graft-versushost reaction, may be obtained from multiple tissues of individual patients, and these cells are easily cultured, amplified, and purified (Goldberg et al, 2017;Guadix et al, 2017). MSCs are widely used in cartilage repair and regeneration as seed cells without concerns regarding increasing the risk of cancer (Hernigou et al, 2013;Liu et al, 2018;Han et al, 2019). An increasing number of studies have suggested that peripheral blood (PB) is a potential alternative source of MSCs, which have shown similar chondrogenic differentiation potential with bone marrow-derived MSCs (BM-MSCs) in both in vitro and in vivo studies (Fu et al, 2014a;Wang et al, 2016a).…”

Injectable Cholesterol‐Enhanced Stereocomplex Polylactide Thermogel Loading Chondrocytes for Optimized Cartilage Regeneration

“…Subsequently, the mechanical properties of the engineered cartilage were measured using a cyto‐nanoindentation technique and compression testing, mechanical parameters of reduced moduli and hardness were quantified according to the load–displacement curves in different groups ( Figure A). As depicted in Figure B,C, the reduced modulus and hardness of scPLA–Chol gel group were 2.24 ± 0.29 GPa and 122.26 ± 9.45 kPa compared to 3.24 ± 0.35 GPa and 179.24 ± 16.54 kPa for native cartilage, respectively . Although these two parameters of neocartilage in the scPLA–Chol gel group cannot catch up to that of healthy cartilage, they were significantly higher than those by scPLA gel (1.71 ± 0.34 GPa and 104.82 ± 3.42 kPa).…”

“…The introduction of hydrophobic cholesterol into 4‐arm PEG–PLA improved the stability of the resulting assemblies and promoted the further heat‐induced aggregation and gel transition. To withstand the in vivo physiological forces, especially in large defects and joint resurfacing, excellent mechanical property of scaffolds is required for the support of regenerative tissue . So, the improvement of mechanical strength enables scPLA–Chol as a good candidate for in vivo cartilage engineering even under weight‐bearing conditions.…”

ROS‐Sensitive Degradable PEG–PCL–PEG Micellar Thermogel

“…The storage modulus ( G ′) of the aqueous polymer solution (36.0 wt%) increased from 0.01 to 1170 Pa as the temperature increased from 20 to 37 °C. G′ crossed over the loss modulus ( G ”) at 34.6 °C, indicating that the elastic component overwhelmed viscous component, which corresponds to sol‐to‐gel transition ( Figure a) . 1 H NMR spectra of the PEG–PCL–PEG were compared in CDCl 3 and D 2 O (Figure b).…”