Plasticity Comparison of Two Stem Cell Sources with Different Hox Gene Expression Profiles in Response to Cobalt Chloride Treatment during Chondrogenic Differentiation

The limited self-repair capacity of articular cartilage is a challenge for healing injuries. While mesenchymal stem/stromal cells (MSCs) are a promising approach for tissue regeneration, the criteria for selecting a suitable cell source remain undefined. To propose a molecular criterion, dental pulp stem cells (DPSCs) with a Hox-negative expression pattern and bone marrow mesenchymal stromal cells (BMSCs), which actively express Hox genes, were differentiated towards chondrocytes in 3D pellets, employing a two-step protocol. The MSCs' response to preconditioning by cobalt chloride (CoCl2), a hypoxia-mimicking agent, was explored in an assessment of the chondrogenic differentiation's efficiency using morphological, histochemical, immunohistochemical, and biochemical experiments. The preconditioned DPSC pellets exhibited significantly elevated levels of collagen II and glycosaminoglycans (GAGs) and reduced levels of the hypertrophic marker collagen X. No significant effect on GAGs production was observed in the preconditioned BMSC pellets, but collagen II and collagen X levels were elevated. While preconditioning did not modify the ALP specific activity in either cell type, it was notably lower in the DPSCs differentiated pellets compared to their BMSCs counterparts. These results could be interpreted as demonstrating the higher plasticity of DPSCs compared to BMSCs, suggesting the contribution of their unique molecular characteristics, including their negative Hox expression pattern, to promote a chondrogenic differentiation potential. Consequently, DPSCs could be considered compelling candidates for future cartilage cell therapy.

Role of Platelet-Rich Plasma Gel in Promoting Wound Healing Based on Medical Images of Wounds

A wound is the pathological change of soft tissue under normal skin caused by various factors, such as collision, contusion, hot crush, avulsion, corrosive chemicals, operations, excessive wound tension after operations, local pressure that cannot be relieved for a long time, liquid immersion, local infection, and rejection reactions caused by allogeneic substances. The skin itself or its underlying soft tissue loses its integrity and continuity, thus losing its normal physiological function. Medical image analysis is a medical term that refers to the interdisciplinary fields of integrated medical imaging, artificial intelligence, digital image processing and analysis, mathematical modeling, and numerical algorithms. According to the time of wound formation, they can be divided into acute and chronic wounds. The common acute wounds include lacerations caused by trauma, surgical incisions, burns, and donor sites formed after skin graft operations. This article mainly studies the role of platelet-rich plasma gel nanocomposites in promoting wound healing. It is proven that ptt-rich plasma gel can significantly promote tissue repair and regeneration and accelerate wound healing in patients with severe burns. The atomic number of the nanocomposite has a better treatment effect on the nanoparticle approach. In this paper, chitosan nanocomposite membrane, nanocomposite algorithm, and the calculation method of enthalpy of formation of high alloy nanomaterials were used to study the role of ptt-rich plasma gel combined chitosan nanocomposite membrane loaded bone marrow stromal cells in promoting wound healing, and its effects were applied to the repair of special site burns, special burns, and different age burns. Good wound repair benefits from the correct treatment of the wound, which directly affects the stability and development of the internal environment. The difference in healing time between the two groups was statistically significant, and the recovery time of the PRP group was 0.001 less than that of the control group. The results showed that the wound healing time of the PRP group was significantly shorter than that of the control group (P < 0.05); after treatment, the content of VEGF in the wound tissue of the two groups increased, especially in the PRP group; the effective rate of the PRP group was 75.0%, which was higher than 68.8% of the control group. It can play an important role in the regulation of expression and the pathophysiological process of wound healing.

Silica/Protein and Silica/Polysaccharide Interactions and Their Contributions to the Functional Properties of Derived Hybrid Wound Dressing Hydrogels

Multifunctional and biocompatible hydrogels are on the focus of wound healing treatments. Protein and polysaccharides silica hybrids are interesting wound dressing alternatives. The objective of this review is to answer questions such as why silica for wound dressings reinforcement? What are the roles and contributions of silane precursors and silica on the functional properties of hydrogel wound dressings? The effects of tailoring the porous, morphological, and chemical characteristics of synthetic silicas on the bioactivity of hybrid wound dressings hydrogels are explored in the first part of the review. This is followed by a commented review of the mechanisms of silica/protein and silica/polysaccharide interactions and their impact on the barrier, scaffold, and delivery matrix functions of the derived hydrogels. Such information has important consequences for wound healing and paves the way to multidisciplinary researches on the production, processing, and biomedical application of this kind of hybrid materials.

Improving Fibrin Hydrogels' Mechanical Properties, through Addition of Silica or Chitosan-Silica Materials, for Potential Application as Wound Dressings

Fibrin is a protein-based hydrogel formed during blood coagulation. It can also be produced in vitro from human blood plasma, and it is capable of resisting high deformations. However, after each deformation process, it loses high amounts of water, which subsequently makes it mechanically unstable and, finally, difficult to manipulate. The objective of this work was to overcome the in vitro fibrin mechanical instability. The strategy consists of adding silica or chitosan-silica materials and comparing how the different materials electrokinetic-surface properties affect the achieved improvement. The siliceous materials electrostatic and steric stabilization mechanisms, together with plasma protein adsorption on their surfaces, were corroborated by DLS and ζ-potential measurements before fibrin gelling. These properties avoid phase separation, favoring homogeneous incorporation of the solid into the forming fibrin network. Young's modulus of modified fibrin hydrogels was evaluated by AFM to quantitatively measure stiffness. It increased 2.5 times with the addition of 4 mg/mL silica. A similar improvement was achieved with only 0.7 mg/mL chitosan-silica, which highlighted the contribution of hydrophilic chitosan chains to fibrinogen crosslinking. Moreover, these chains avoided the fibroblast growth inhibition onto modified fibrin hydrogels 3D culture observed with silica. In conclusion, 0.7 mg/mL chitosan-silica improved the mechanical stability of fibrin hydrogels with low risks of cytotoxicity. This easy-to-manipulate modified fibrin hydrogel makes it suitable as a wound dressing biomaterial.

Recent advances in the application of mesoporous silica-based nanomaterials for bone tissue engineering

Silica nanomaterials (SNMs) and their composites have recently been investigated as scaffolds for bone tissue engineering. SNM scaffolds possess the ability to encourage bone cell growth and also allow the simultaneous delivery of biologically active biomolecules that are encapsulated in the mesopores. Their high mechanical strength, low cytotoxicity, ability to stimulate both the proliferation and osteogenic differentiation of progenitor cells make the SNMs appropriate scaffolds. Their physiochemical properties facilitate the cell spreading process, allow easy access to nutrients and help the cell-cell communication process during bone tissue engineering. The ability to deliver small biomolecules, such as dexamethasone, different growth factors, vitamins and mineral ions depends on the morphology, porosity, and crystallinity of SNMs and their composites with other polymeric materials. In this review, the abilities of SNMs to perform as suitable scaffolds for bone tissue engineering are comprehensively discussed.

3D printable SiO2 nanoparticle ink for patient specific bone regeneration

3D printing of a complex and irregular virtual defect using SiO₂ nanoparticle and hydrogel composite ink for patient specific defect fabrication.