Surface modification of bundle-type polyamide fiber nonwoven with collagen to improve its hydrophilicity

Enhancing the function of PLGA-collagen scaffold by incorporating TGF-β1-loaded PLGA-PEG-PLGA nanoparticles for cartilage tissue engineering using human dental pulp stem cells

Since cartilage has a limited capacity for self-regeneration, treating cartilage degenerative disorders is a long-standing difficulty in orthopedic medicine. Researchers have scrutinized cartilage tissue regeneration to handle the deficiency of cartilage restoration capacity. This investigation proposed to compose an innovative nanocomposite biomaterial that enhances growth factor delivery to the injured cartilage site. Here, we describe the design and development of the biocompatible poly(lactide-co-glycolide) acid-collagen/poly(lactide-co-glycolide)-poly(ethylene glycol)-poly(lactide-co-glycolide) (PLGA-collagen/PLGA-PEG-PLGA) nanocomposite hydrogel containing transforming growth factor-β1 (TGF-β1). PLGA-PEG-PLGA nanoparticles were employed as a delivery system embedding TGF-β1 as an articular cartilage repair therapeutic agent. This study evaluates various physicochemical aspects of fabricated scaffolds by ¹HNMR, FT-IR, SEM, BET, and DLS methods. The physicochemical features of the developed scaffolds, including porosity, density, degradation, swelling ratio, mechanical properties, morphologies, BET, ELISA, and cytotoxicity were assessed. The cell viability was investigated with the MTT test. Chondrogenic differentiation was assessed via Alcian blue staining and RT-PCR. In real-time PCR testing, the expression of Sox-9, collagen type II, and aggrecan genes was monitored. According to the results, human dental pulp stem cells (hDPSCs) exhibited high adhesion, proliferation, and differentiation on PLGA-collagen/PLGA-PEG-PLGA-TGFβ1 nanocomposite scaffolds compared to the control groups. SEM images displayed suitable cell adhesion and distribution of hDPSCs throughout the scaffolds. RT-PCR assay data displayed that TGF-β1 loaded PLGA-PEG-PLGA nanoparticles puts forward chondroblast differentiation in hDPSCs through the expression of chondrogenic genes. The findings revealed that PLGA-collagen/PLGA-PEG-PLGA-TGF-β1 nanocomposite hydrogel can be utilized as a supportive platform to support hDPSCs differentiation by implementing specific physio-chemical features.

Construction of a Novel Substrate of Unfigured Islands-in-Sea Microfiber Synthetic Leather Based on Waste Collagen

This study is to introduce waste collagen into an unfigured islands-in-sea microfiber nonwoven material, replacing the polyurethane impregnation section of the traditional manufacturing process with the collagen impregnation process. The modified collagen was first impregnated in polyamide/low-density polyethylene (PA/LDPE) fiber nonwoven to form a film. Then the low-density polyethylene component was extracted and dissolved in toluene, resulting in a collagen-based microfiber nonwoven substrate. Waste collagen was first modified to introduce C=C into the molecular chain to obtain vinyl collagen (CMA), and then the following film formation conditions for CMA were studied: 73% degree of substitution (DS), 3 h cross-linking time, and 0.005-0.01 wt % initiator concentration. Then, the preparation of CMA-PA/LDPE and toluene extraction processes were investigated. The optimum toluene extraction conditions were obtained as an extraction temperature of 85 °C and an extraction time of 110 min. The properties of the nonwoven materials were compared before (CMA-PA/LDPE) and after (PA-CMA) extraction. It was found that the homogeneity, tensile strength, and static moisture permeability of the PA-CMA materials prepared by CMA with 50 and 73% DS were all superior to those of PA/LDPE. In particular, the static moisture permeability of PA-CMA (691.6 mg/10 cm2·24 h) increased by 36.2% compared to the microfiber synthetic leather substrate currently in the market. Using scanning electron microscopy (SEM), the continuity of a film of PA-CMA with 73% DS was observed to be better and the fibers were differentiated and relatively tighter fiber-to-fiber gap. The studied novel green process can eliminate the large amount of dimethylformamide (DMF) pollution caused by the current solvent-based polyurethane impregnation process.