ABSTRACT
Acellular dermal matrix (ADM) shows promise for cartilage regeneration and repair. However, an effective decellularization technique that removes cellular components while preserving the extracellular matrix, the transformation of 2D-ADM into a suitable 3D scaffold with porosity and the enhancement of bioactive and biomechanical properties in the 3D-ADM scaffold are yet to be fully addressed. In this study, we present an innovative decellularization method involving 0.125% trypsin and 0.5% SDS and a 1% Triton X-100 solution for preparing ADM and converting 2D-ADM into 3D-ADM scaffolds. These scaffolds exhibit favorable physicochemical properties, exceptional biocompatibility and significant potential for driving cartilage regeneration in vitro and in vivo. To further enhance the cartilage regeneration potential of 3D-ADM scaffolds, we incorporated porcine-derived small intestinal submucosa (SIS) for bioactivity and calcium sulfate hemihydrate (CSH) for biomechanical reinforcement. The resulting 3D-ADM+SIS scaffolds displayed heightened biological activity, while the 3D-ADM+CSH scaffolds notably bolstered biomechanical strength. Both scaffold types showed promise for cartilage regeneration and repair in vitro and in vivo, with considerable improvements observed in repairing cartilage defects within a rabbit articular cartilage model. In summary, this research introduces a versatile 3D-ADM scaffold with customizable bioactive and biomechanical properties, poised to revolutionize the field of cartilage regeneration.
ABSTRACT
Regenerative cartilage replacements are increasingly required in clinical settings for various defect repairs, including bronchial cartilage deficiency, articular cartilage injury, and microtia reconstruction. Poly (glycerol sebacate) (PGS) is a widely used bioelastomer that has been developed for various regenerative medicine applications because of its excellent elasticity, biodegradability, and biocompatibility. However, because of inadequate active groups, strong hydrophobicity, and limited ink extrusion accuracy, 3D printed PGS scaffolds may cause insufficient bioactivity, inefficient cell inoculation, and inconsistent cellular composition, which seriously hinders its further cartilage regenerative application. Here, we combined 3D printed PGS frameworks with an encapsulated gelatin hydrogel to fabricate a PGS@Gel composite scaffold. PGS@Gel scaffolds have a controllable porous microstructure, with suitable pore sizes and enhanced hydrophilia, which could significantly promote the cells' penetration and adhesion for efficient chondrocyte inoculation. Furthermore, the outstanding elasticity and fatigue durability of the PGS framework enabled the regenerated cartilage built by the PGS@Gel scaffolds to resist the dynamic in vivo environment and maintain its original morphology. Importantly, PGS@Gel scaffolds increased the rate of cartilage regeneration concurrent with scaffold degradation. The scaffold was gradually degraded and integrated to form uniform, dense, and mature regenerated cartilage tissue with little scaffold residue.
ABSTRACT
Tissue engineering is emerging as a promising approach for cartilage regeneration and repair. Endowing scaffolds with cartilaginous bioactivity to obtain bionic microenvironment and regulating the matching of scaffold degradation and regeneration play a crucial role in cartilage regeneration. Poly(glycerol sebacate) (PGS) is a representative thermosetting bioelastomer known for its elasticity, biodegradability, and biocompatibility and is widely used in tissue engineering. However, the modification and drug loading of the PGS scaffold is still a key challenge due to its high temperature curing conditions and limited reactive groups, which seriously hinders its further functional application. Here, a simple versatile new strategy of super swelling-absorption and cross-linked networks locking is presented to successfully create the 3D printed PGS-CS/Gel scaffold for the first time based on FDA-approved PGS, gelatin (Gel) and chondroitin sulfate (CS). The PGS-CS/Gel scaffold exhibits the desirable synergistic properties of well-organized hierarchical structures, excellent elasticity, improved hydrophilicity, and cartilaginous bioactivity, which can promote the adhesion, proliferation, and migration of chondrocytes. Importantly, the rate of cartilage regeneration can be well-matched with degradation of PGS-CS/Gel scaffold, and achieve uniform and mature cartilage tissue without scaffold residual. The bioactive scaffold can successfully repair cartilage in a rabbit trochlear groove defect model indicating a promising prospect of clinical transformation.
Subject(s)
Cartilage , Tissue Scaffolds , Animals , Rabbits , Tissue Scaffolds/chemistry , Tissue Engineering/methods , Regeneration , Printing, Three-DimensionalABSTRACT
Follicular fluid serves a crucial role in follicular development and oocyte maturation. Increasing evidence indicates that follicular fluid is rich in proteins and functional cells. In addition to oocyte cells, follicular fluid contains granulosa, thecal and ovarian surface epithelial cells. Granulosa cells (GCs) represent the predominant somatic cell type of the ovarian follicle and are involved in steroidogenesis and folliculogenesis. However, the long-term culture of GCs in vitro remains challenging. The present study aimed to extend the culture of GCs in vitro. Human GCs were collected from the follicular fluid of patients included in an in vitro fertilization program and cultured in the presence of conditioned medium obtained from mouse embryonic fibroblasts. GCs were cultured for over a year and 130 passages, and the population doubling time was ~22 h. Cells presented epithelial-like morphology and a cobblestone-like appearance when they reached confluence. Flow cytometric analysis demonstrated that cells expressed CD29, CD166 and CD49f but not CD31, CD34, CD45, CD90, CD105 or CD13. Immunofluorescence staining revealed that cells expressed follicle stimulating hormone receptor, luteinizing hormone receptor and cytochrome P450 aromatase, which was confirmed by reverse transcription-quantitative polymerase chain reaction. In the presence of androstenedione, cells secreted estradiol. In addition, estradiol level was further stimulated by dibutyryl cAMP treatment. In addition, intracellular cAMP and progesterone expression levels were upregulated by follicle stimulating hormone and/or human chorionic gonadotropin. Furthermore, cells survived in severe combined immunodeficiency mice following intra-ovarian injection. Histological analysis revealed that certain cells formed follicle-like structures. The results from the present study suggested that immortalized GCs may be a useful tool for further research on GC and improve the clinical application of drugs such as follicle-stimulating hormone or human chorionic gonadotropin.
ABSTRACT
OBJECTIVES: To assess the applicability of a novel hybrid dextran-gadolinium nanoparticles (NPs) as high-relaxivity T1 magnetic resonance imaging (MRI) contrast agent for mapping the sentinel lymph node (SLN). METHODS: Dextran-bis-acrylamide-polyacrylic acid (Dex-MBA-PAA) NPs were synthesized through a self-assembly assisted approach and complexed with multiple chelated gadolinium (Gd) (III) ions. After their characterization was validated, they were used to mapping SLNs by MRI in Wistar rats, and their biosafety was evaluated. RESULTS: Dextran-MBA-polyacrylic acid-Gd NPs have suitable particle size and much higher longitudinal relaxivity (r1) than that of commonly used clinical MRI contrast agents (eg, gadopentetic acid dimeglumine salt injection). The in vivo T1-weighted MRI results revealed their effectiveness at mapping SLNs. And their biological safety was also verified. CONCLUSIONS: Dextran-MBA-polyacrylic acid-Gd NPs were synthesized and validated by in vitro and in vivo experiments for their ability to visualize SLNs by MRI with accurate positioning and excellent biosafety, and they have great potential for clinical SLN mapping.
