The use of decellularised matrices as scaffolds offers the advantage of great similarity with the tissue to be replaced. Moreover, decellularised tissues and organs can be repopulated with the patient’s own cells to produce bespoke therapies. Great progress has been made in research and development of decellularised scaffolds, and more recently, these materials are being used in exciting new areas like hydrogels and bioinks. However, much effort is still needed towards preserving the original extracellular matrix composition, especially its minor components, assessing its functionality and scaling up for large tissues and organs. Emphasis should also be placed on developing new decellularisation methods and establishing minimal criteria for assessing the success of the decellularisation process. The aim of this review is to critically review the existing literature on decellularised scaffolds, especially on the preparation of these matrices, and point out areas for improvement, finishing with alternative uses of decellularised scaffolds other than tissue and organ reconstruction. Such uses include three-dimensional ex vivo platforms for idiopathic diseases and cancer modelling.

Current gold standard to treat soft tissue injuries caused by trauma and pathological condition are autografts and off the shelf fillers, but they have inherent weaknesses like donor site morbidity, immuno-compatibility and graft failure. To overcome these limitations, tissue-engineered polymers are seeded with stem cells to improve the potential to restore tissue function. However, their interaction with native tissue is poorly understood so far. To study these interactions and improve outcomes, we have fabricated scaffolds from natural polymers (collagen, fibrin and elastin) by custom-designed processes and their material properties such as surface morphology, swelling, wettability and chemical cross-linking ability were characterised. By using 3D scaffolds, we comprehensive assessed survival, proliferation and phenotype of adipose-derived stem cells in vitro. In vivo, scaffolds were seeded with adipose-derived stem cells and implanted in a rodent model, with X-ray microtomography, histology and immunohistochemistry as read-outs. Collagen-based materials showed higher cell adhesion and proliferation in vitro as well as higher adipogenic properties in vivo. In contrast, fibrin demonstrated poor cellular and adipogenesis properties but higher angiogenesis. Elastin formed the most porous scaffold, with cells displaying a non-aggregated morphology in vitro while in vivo elastin was the most degraded scaffold. These findings of how polymers present in the natural polymers mimicking ECM and seeded with stem cells affect adipogenesis in vitro and in vivo can open avenues to design 3D grafts for soft tissue repair.

Control of cell-surface interaction is necessary for biomaterial applications such as cell sheets, intelligent cell culture surfaces, or functional coatings. In this paper, we propose the emergent property of cell...

Chronic leg ulcers (CLUs) are full thickness wounds that usually occur between the ankle and knee, fail to heal after 3 months of standard treatment, or are not entirely healed at 12 months. CLUs present a considerable burden on patients, subjecting them to severe pain and distress, while healthcare systems suffer immense costs and loss of resources. The poor healing outcome of the standard treatment of CLUs generates an urgent clinical need to find effective solutions for these wounds. Tissue Engineering and Biomaterials Science offer exciting prospects for the treatment of CLUs, using a broad range of skin substitutes or scaffolds, and dressings. In this review, we summarize and discuss the various types of scaffolds used clinically in the treatment of CLUs. Their structure and therapeutic effects are described, and for each scaffold type representative examples are discussed, supported by clinical trials. Silver dressings are also reviewed due to their reported benefits in the healing of leg ulcers, as well as recent studies on new dermal scaffolds, reporting on clinical results where available. We conclude by arguing there is a further need for tissue-engineered products specifically designed and bioengineered to treat these wounds and we propose a series of properties that a biomaterial for CLUs should possess, with the intention of focusing efforts on finding an effective treatment.