Self-agglomerated collagen patterns govern cell behaviour

Reciprocity between cells and their surrounding extracellular matrix is one of the main drivers for cellular function and, in turn, matrix maintenance and remodelling. Unravelling how cells respond to their environment is key in understanding mechanisms of health and disease. In all these examples, matrix anisotropy is an important element, since it can alter the cell shape and fate. In this work, the objective is to develop and exploit easy-to-produce platforms that can be used to study the cellular response to natural proteins assembled into diverse topographical cues. We demonstrate a robust and simple approach to form collagen substrates with different topographies by evaporating droplets of a collagen solution. Upon evaporation of the collagen solution, a stain of collagen is left behind, composed of three regions with a distinct pattern: an isotropic region, a concentric ring pattern, and a radially oriented region. The formation and size of these regions can be controlled by the evaporation rate of the droplet and initial collagen concentration. The patterns form topographical cues inducing a pattern-specific cell (tenocyte) morphology, density, and proliferation. Rapid and cost-effective production of different self-agglomerated collagen topographies and their interfaces enables further study of the cell shape-phenotype relationship in vitro. Substrate topography and in analogy tissue architecture remains a cue that can and will be used to steer and understand cell function in vitro, which in turn can be applied in vivo, e.g. in optimizing tissue engineering applications.

Oriented collagen films with high Young's modulus by self-assembly on micrometer grooved polydimethylsiloxane

We report on the fabrication of oriented collagen films by drying a dilute collagen solution on a polydimethylsiloxane (PDMS) substrate with a micrometer grooved surface.

Modification of Collagen Properties with Ferulic Acid

Collagen materials are widely used in biomedicine and in cosmetics. However, their properties require improvement for several reasons. In this work, collagen solution as well as collagen films were modified by the addition of ferulic acid (FA). Thin collagen films containing FA were obtained by solvent evaporation. The properties of collagen solution have been studied by steady shear tests. The structure and surface properties of collagen thin films were studied. It was found that for collagen solution with 5% addition of FA, the apparent viscosity was the highest, whereas the collagen solutions with other additions of FA (1%, 2%, and 10%), no significant difference in the apparent viscosity was observed. Thin films prepared from collagen with 1 and 2% FA addition were homogeneous, whereas films with 5% and 10% FA showed irregularity in the surface properties. Mechanical properties, such as maximum tensile strength and elongation at break, were significantly higher for films with 10% FA than for films with smaller amount of FA. Young modulus was similar for films with 1% and 10% FA addition, but bigger than for 2% and 5% of FA in collagen films. The cross-linking of collagen with ferulic acid meant that prepared thin films were elastic with better mechanical properties than collagen films.

Concentration and Purification of CollagenProteins by Ultrafiltration

The objective of the present study was to evaluate the performance of the ultrafiltration process on the recovery of collagen solution constituents at laboratory scale, using a tangential flow filtration, with flat regenerated cellulose membrane (5000 Da). Also permeate flows were evaluated along with the physicochemical characteristics of the concentrates, the permeates and feed solutions. The regenerated cellulose membranes were morphological studied by electron microscopy and characterized by water solutions permeation at different pressures. Keywords: collagen, concentration, protein, purification, ultrafiltration

Preparation of three-dimensional multilayer ECM-simulated woven/knitted fabric composite scaffolds for potential tissue engineering applications

The extracellular matrix (ECM), with its multilayer fiber structure, regulates diverse functions including cell proliferation, migration, differentiation and tissue regeneration effects. To mimic and replace the native ECM, the structures and properties of three single-layer fabric substrates including warp/weft-knitted and woven fabrics were analyzed, then two-layer warp/weft-knitted composite fabrics prepared by polyurethane (PU) bonding, and woven composite fabrics prepared by polycaprolactone (PCL)/collagen solution bonding or PU bonding, were studied. After PCL/collagen solution bonding or PU bonding, properties such as pore diameter, air permeability, stress and the contact angle of composite fabrics decreased by some degree, while fiber diameter, thickness and the thermal conductivity of composite fabrics increased. In combination with fiber diameter, pore diameter and physical properties, we know that warp- or weft-knitted composite fabrics are ideal scaffolda for potential applications in nerve, myocardium and tendon tissue engineering.

Effectiveness of Endoscopic Application of Type I Human Collagen Solution in Treatment of Inhalation Injury

The purpose of the studywas to determine the morphological characteristics of the repair process of the tracheal and bronchial mucosa after sanitation bronchoscopy using type I human collagen solution in patients with an inhalation injury (II).Materials and methods. An open-label, randomized, prospective study included 59 patients with inhalation injury (2—3 severity degree according to the classification of Yu. V. Sinev and A. Yu. Skripal'. The main group consisted of 29 patients. They underwent a sanitation bronchoscopy using type I human collagen solution applied onto erosive and ulcerative lesions of the mucous membrane. The reference group consisted of 30 patients who underwent sanitation bronchoscopy in accordance with the standards of medical care. In order to assess the morphological dynamics of the repair process of the mucous membrane, a morphological study of the bioptate obtained during endoscopic studies was carried out. The solution for the application was prepared by acid extraction of type I human collagen from ligaments and tendons as described earlier (Russian Federation invention patent No. RU 2591544 C1).Results.Complete epithelization of the tracheal and bronchial mucosa occurred significantly earlier (4 (3; 7) days) in patients with the 2nd degree inhalation injury when using type 1 collagen application, than in those without the application (7 (4; 9) days) (n=15 andn=21 respectively;U=49.5;P=0.0004). In the case of the 3rd degree inhalation injury, coating of ulcers of the tracheobronchial tree mucosa with the collagen solution also significantly reduced the epithelialization period on average to 8 (7; 10) days, while after the standard sanitation bronchoscopy, this period was 17 (12; 22) days (n=14 andn=9 respectively; U=1;P=0.0001). The morphological changes in patients of the main group were characterized by the absence of signs of a purulent inflammation, early appearance of macrophages and lymphocytes, and covering of type I collagen by simple cuboidal epithelium, while in the reference group, there was a severe purulent inflammation manifested by polymorphonuclear leukocyte infiltration.Conclusion.The sanitation bronchoscopy with simultaneous closure of the damaged areas of the mucous membrane with the type I human collagen solution results in relief of the inflammatory process which is confirmed by morphological studies.