Viscoelastic, physical, and bio-degradable properties of dermal scaffolds and related cell behaviour.

Dermal scaffolds promote healing of debilitating skin injuries caused by burns and chronic skin conditions. Currently available products present disadvantages and therefore, there is still a clinical need for developing new dermal substitutes. This study aimed at comparing the viscoelastic, physical and bio-degradable properties of two dermal scaffolds, the collagen-based and clinically well established Integra(®) and a novel fibrin-based dermal scaffold developed at our laboratory called Smart Matrix(®), to further evaluate our previous published findings that suggested a higher influx of cells, reduced wound contraction and less scarring for Smart Matrix(®) when used in vivo. Rheological results showed that Integra(®) (G' = 313.74 kPa) is mechanically stronger than Smart Matrix(®) (G' = 8.26 kPa), due to the presence of the silicone backing layer in Integra(®). Micro-pores were observed on both dermal scaffolds, although nano-pores as well as densely packed nano-fibres were only observed for Smart Matrix(®). Average surface roughness was higher for Smart Matrix(®) (Sa = 114.776 nm) than for Integra(®) (Sa = 75.565 nm). Both scaffolds possess a highly porous structure (80-90%) and display a range of pore micro-sizes that represent the actual in vivo scenario. In vitro proteolytic bio-degradation suggested that Smart Matrix(®) would degrade faster upon implantation in vivo than Integra(®). For both scaffolds, the enzymatic digestion occurs via bulk degradation. These observed differences could affect cell behaviour on both scaffolds. Our results suggest that fine-tuning of scaffolds' viscoelastic, physical and bio-degradable properties can maximise cell behaviour in terms of attachment, proliferation and infiltration, which are essential for tissue repair.

Albumin removal from human fibrinogen preparations for manufacturing human fibrin-based biomaterials.

Commercially available two component human fibrin sealants are commonly used to manufacture human fibrin-based biomaterials. However, this method is costly and allows little room for further tuning of the biomaterial. Human fibrinogen solutions offer a more cost-effective and versatile alternative to manufacture human fibrin-based biomaterials. Yet, human fibrinogen is highly unstable and contains certain impurities like human albumin. Within the context of biomaterials and tissue engineering we offer a simple yet novel solution based on classical biochemical techniques to significantly reduce albumin in human fibrinogen solutions. This method can be used for various tissue engineering and biomedical applications as an initial step in the manufacturing of human fibrin-based biomaterials to optimise their regenerative application.