The Degradation of Synthetic Polymeric Scaffolds With Strut-like Architecture Influences the Mechanics-dependent Repair Process of an Osteochondral Defect in Silico

Alginate-gelatin composite hydrogels loading zeolitic imidazolate framework-8 (ZIF-8) nanoparticles on gauze for burn wound healing: In vitro and in vivo studies

This study addresses the limitations of traditional antibiotic treatments for burn wound dressings, which often lead to microbial resistance. It explores the development of innovative burn wound dressings by incorporating Zeolitic Imidazolate Framework-8 (ZIF-8) into alginate-gelatin (Al-Gl) hydrogels on gauze. Al-Gl patches with 0 %, 1 %, and 4 % ZIF-8 were fabricated and characterized using XRD, FTIR, FESEM, and EDX. Swelling, degradation, antibacterial activity, and biocompatibility were also evaluated, alongside in vivo wound healing using a Wistar rat model. FESEM confirmed ZIF-8 nanoparticles with hexagonal morphology (170-220 nm). The swelling ratio decreased from 600 % (Al-Gl 0 %) to 130 % (Al-Gl 4 %) over 10 h, and degradation rates increased from 50 % to over 70 %. Al-Gl 4 % patches demonstrated 99 % antibacterial efficacy against E. coli and S. aureus, compared to <5 % in Al-Gl 0 %. Biocompatibility was confirmed with over 90 % cell viability in MTT assays. In vivo studies showed Al-Gl 4 % achieved 89.40 % ± 3.21 % wound closure, significantly outperforming controls. Histological analyses confirmed enhanced tissue regeneration. These findings demonstrate that ZIF-8 significantly boosts antibacterial properties and wound healing, positioning ZIF-8 hydrogels as promising candidates for advanced burn wound care.

Application of gelatin-based composites in bone tissue engineering

Natural bone tissue has the certain function of self-regeneration and repair, but it is difficult to repair large bone damage. Recently, although autologous bone grafting is the "gold standard" for improving bone repair, it has high cost, few donor sources. Besides, allogeneic bone grafting causes greater immune reactions, which hardly meet clinical needs. The bone tissue engineering (BTE) has been developed to promote bone repair. Gelatin, due to its biocompatibility, receives a great deal of attention in the BTE research field. However, the disadvantages of natural gelatin are poor mechanical properties and single structural property. With the development of BTE, gelatin is often used in combination with a range of natural, synthetic polymers, and inorganic materials to achieve synergistic effects for the complex physiological process of bone repair. The review delves into the fundamental structure and unique properties of gelatin, as well as the excellent properties necessary for bone scaffold materials. Then this review explores the application of modified gelatin three-dimensional (3D) scaffolds with various structures in bone repair, including 3D fiber scaffolds, hydrogels, and nanoparticles. In addition, the review focuses on the excellent efficacy of composite bone tissue scaffolds consisting of modified gelatin, various natural or synthetic polymeric materials, as well as bioactive ceramics and inorganic metallic/non-metallic materials in the repair of bone defects. The combination of these gelatin-based composite scaffolds provides new ideas for the design of scaffold materials for bone repair with good biosafety.

Comparing the osteogenesis outcomes of different lumbar interbody fusions (A/O/X/T/PLIF) by evaluating their mechano-driven fusion processes

BACKGROUND

In lumbar interbody fusion (LIF), achieving proper fusion status requires osteogenesis to occur in the disc space. Current LIF techniques, including anterior, oblique, lateral, transforaminal, and posterior LIF (A/O/X/T/PLIF), may result in varying osteogenesis outcomes due to differences in biomechanical characteristics.

METHODS

A mechano-regulation algorithm was developed to predict the fusion processes of A/O/X/T/PLIF based on finite element modeling and iterative evaluations of the mechanobiological activities of mesenchymal stem cells (MSCs) and their differentiated cells (osteoblasts, chondrocytes, and fibroblasts). Fusion occurred in the grafting region, and each differentiated cell type generated the corresponding tissue proportional to its concentration. The corresponding osteogenesis volume was calculated by multiplying the osteoblast concentration by the grafting volume.

RESULTS

TLIF and ALIF achieved markedly greater osteogenesis volumes than did PLIF and O/XLIF (5.46, 5.12, 4.26, and 3.15 cm3, respectively). Grafting volume and cage size were the main factors influencing the osteogenesis outcome in patients treated with LIF. A large grafting volume allowed more osteoblasts (bone tissues) to be accommodated in the disc space. A small cage size reduced the cage/endplate ratio and therefore decreased the stiffness of the LIF. This led to a larger osteogenesis region to promote osteoblastic differentiation of MSCs and osteoblast proliferation (bone regeneration), which subsequently increased the bone fraction in the grafting space.

CONCLUSION

TLIF and ALIF produced more favorable biomechanical environments for osteogenesis than did PLIF and O/XLIF. A small cage and a large grafting volume improve osteogenesis by facilitating osteogenesis-related cell activities driven by mechanical forces.

Bilayer regenerated cellulose/quaternized chitosan-hyaluronic acid/collagen electrospun scaffold for potential wound healing applications

In this study, a bilayer electrospun scaffold has been prepared using regenerated cellulose (RC)/quaternized chitosan (CS) as the primary layer and collagen/hyaluronic acid (HA) as the second layer. An approximate 48 mol% substituted (estimated from 1H NMR) quaternized CS was used in this study. Both layers were crosslinked with EDC/NHS, reflecting an increase in UTS (2.29 MPa for the bilayer scaffold compared to 1.82 MPa for the RC scaffold). Initial cell viability, cell adhesion and proliferation, FDA staining for live cells, and hydroxyproline release rate from cells were evaluated with L929 mouse fibroblast cells. Also, detailed in vitro studies were performed using HADF cells, which include MTT Assay, Live/Dead imaging, DAPI staining, gene expression of PDGF, VEGF-A, and COL1 in RT-PCR, and cell cycle analysis. The collagen/HA-based bilayer scaffold depicted a 9.76-fold increase of VEGF-A compared to a 2.1-fold increase for the RC scaffold, indicating angiogenesis and vascularization potential. In vitro scratch assay was performed to observe the migration of cells in simulated wounds. Antimicrobial, antioxidant, and protease inhibitory activity were further performed, and overall, the primary results highlighted the potential usage of bilayer scaffold in wound healing applications.

The Long and Winding Road to Cardiac Regeneration

Cardiac regeneration is a critical endeavor in the treatment of heart diseases, aimed at repairing and enhancing the structure and function of damaged myocardium. This review offers a comprehensive overview of current advancements and strategies in cardiac regeneration, with a specific focus on regenerative medicine and tissue engineering-based approaches. Stem cell-based therapies, which involve the utilization of adult stem cells and pluripotent stem cells hold immense potential for replenishing lost cardiomyocytes and facilitating cardiac tissue repair and regeneration. Tissue engineering also plays a prominent role employing synthetic or natural biomaterials, engineering cardiac patches and grafts with suitable properties, and fabricating upscale bioreactors to create functional constructs for cardiac recovery. These constructs can be transplanted into the heart to provide mechanical support and facilitate tissue healing. Additionally, the production of organoids and chips that accurately replicate the structure and function of the whole organ is an area of extensive research. Despite significant progress, several challenges persist in the field of cardiac regeneration. These include enhancing cell survival and engraftment, achieving proper vascularization, and ensuring the long-term functionality of engineered constructs. Overcoming these obstacles and offering effective therapies to restore cardiac function could improve the quality of life for individuals with heart diseases.