Freeze-Drying Process for the Fabrication of Collagen-Based Sponges as Medical Devices in Biomedical Engineering

Comprehensive review on collagen extraction from food by-products and waste as a value-added material

The consumption of animal products has witnessed a significant increase over the years, leading to a growing need for industries to adopt strict waste control measures to mitigate environmental impacts. The disposal of animal waste in landfill can result in diverse and potentially hazardous decomposition by-products. Animal by-products, derived from meat, poultry, seafood and fish industries, offer a substantial raw material source for collagen and gelatin production due to their high protein content. Collagen, being a major protein component of animal tissues, represents an abundant resource that finds application in various chemical and material industries. The demand for collagen-based products continues to grow, yet the availability of primary material remains limited and insufficient to meet projected needs. Consequently, repurposing waste materials that contain collagen provides an opportunity to meet this need while at the same time minimizing the amount of waste that is dumped. This review examines the potential to extract value from the collagen content present in animal-derived waste and by-products. It provides a systematic evaluation of different species groups and discusses various approaches for processing and fabricating repurposed collagen. This review specifically focuses on collagen-based research, encompassing an examination of its physical and chemical properties, as well as the potential for chemical modifications. We have detailed how the research and knowledge built on collagen structure and function will drive the new initiatives that will lead to the development of new products and opportunities in the future. Additionally, it highlights emerging approaches for extracting high-quality protein from waste and discusses efforts to fabricate collagen-based materials leading to the development of new and original products within the chemical, biomedical and physical science-based industries.

Artificial Intelligence (AI) Based Analysis of In Vivo Polymers and Collagen Scaffolds Inducing Vascularization

BACKGROUND/AIM

Biomaterials are essential in modern medicine, both for patients and research. Their ability to acquire and maintain functional vascularization is currently debated. The aim of this study was to evaluate the vascularization induced by two collagen-based scaffolds (with 2D and 3D structures) and one non-collagen scaffold implanted on the chick embryo chorioallantoic membrane (CAM).

MATERIALS AND METHODS

Classical stereomicroscopic image vascular assessment was enhanced with the IKOSA software by using two applications: the CAM assay and the Network Formation Assay, evaluating the vessel branching potential, vascular area, as well as tube length and thickness.

RESULTS

Both collagen-based scaffolds induced non-inflammatory angiogenesis, but the non-collagen scaffold induced a massive inflammation followed by inflammatory-related angiogenesis. Vessels branching points/Region of Interest (Px^2) and Vessel branching points/Vessel total area (Px^2), increased exponentially until day 5 of the experiment certifying a sustained and continuous angiogenic process induced by 3D collagen scaffolds.

CONCLUSION

Collagen-based scaffolds may be more suitable for neovascularization compared to non-collagen scaffolds. The present study demonstrates the potential of the CAM model in combination with AI-based software for the evaluation of vascularization in biomaterials. This approach could help to reduce and replace animal experimentation in the pre-screening of biomaterials.

Bioactive gelatin-sheets as novel biopapers to support prevascularization organized by laser-assisted bioprinting for bone tissue engineering

Despite significant advances in the management of patients with oral cancer, maxillofacial reconstruction after ablative surgery remains a clinical challenge. In bone tissue engineering, biofabrication strategies have been proposed as promising alternatives to solve issues associated with current therapies and to produce bone substitutes that mimic both the structure and function of native bone. Among them, laser-assisted bioprinting (LAB) has emerged as a relevant biofabrication method to print living cells and biomaterials with micrometric resolution onto a receiving substrate, also called 'biopaper'. Recent studies have demonstrated the benefits of prevascularization using LAB to promote vascularization and bone regeneration, but mechanical and biological optimization of the biopaper are needed. The aim of this study was to apply gelatin-sheet fabrication process to the development of a novel biopaper able to support prevascularization organized by LAB for bone tissue engineering applications. Gelatin-based sheets incorporating bioactive glasses (BGs) were produced using various freezing methods and crosslinking (CL) parameters. The different formulations were characterized in terms of microstructural, physical, mechanical, and biological properties in monoculture and coculture. Based on multi-criteria analysis, a rank scoring method was used to identify the most relevant formulations. The selected biopaper underwent additional characterization regarding its ability to support mineralization and vasculogenesis, its bioactivity potential andin vivodegradability. The biopaper 'Gel5wt% BG1wt%-slow freezing-CL160 °C 24 h' was selected as the best candidate, due to its suitable properties including high porosity (91.69 ± 1.55%), swelling ratio (91.61 ± 0.60%), Young modulus (3.97 × 104± 0.97 × 104Pa) but also its great cytocompatibility, osteogenesis and bioactivity properties. The preorganization of human umbilical vein endothelial cell using LAB onto this new biopaper led to the formation of microvascular networks. This biopaper was also shown to be compatible with 3D-molding and 3D-stacking strategies. This work allowed the development of a novel biopaper adapted to LAB with great potential for vascularized bone biofabrication.