Manufacture of a weakly denatured collagen fiber scaffold with excellent biocompatibility and space maintenance ability

Abstract

Although collagen scaffolds have been used for regenerative medicine, they have insufficient mechanical strength. We made a weakly denatured collagen fiber scaffold from a collagen fiber suspension (physiological pH 7.4) through a process of freeze drying and denaturation with heat under low pressure (1 × 10(-1) Pa). Heat treatment formed cross-links between the collagen fibers, providing the scaffold with sufficient mechanical strength to maintain the space for tissue regeneration in vivo. The scaffold was embedded under the back skin of a rat, and biocompatibility and space maintenance ability were examined after 2 weeks. These were evaluated by using the ratio of foreign body giant cells and thickness of the residual scaffold. A weakly denatured collagen fiber scaffold with moderate biocompatibility and space maintenance ability was made by freezing at -10 °C, followed by denaturation at 140 °C for 6 h. In addition, the direction of the collagen fibers in the scaffold was adjusted by cooling the suspension only from the bottom of the container. This process increased the ratio of cells that infiltrated into the scaffold. A weakly denatured collagen fiber scaffold thus made can be used for tissue regeneration or delivery of cells or proteins to a target site.

Optimal dehydrothermal processing conditions to improve biocompatibility and durability of a weakly denatured collagen scaffold

“…In other words, even if a scaffold is physically hard, it will be considered to have poor durability if it has to be removed early owing to a strong foreign body reaction in vivo . Previously, it was shown that a collagen scaffold with durability, biocompatibility, and superior cell infiltration ability could be manufactured by pouring the collagen fiber suspension at a physiological pH of 7.4 into a container that provides orientation to the collagen fibers, followed by freezing at −10°C, drying completely, and treating the fibers at 140°C for 6 h under low pressure (1 × 10 −1 Pa) …”

“…Scaffolds were fabricated as described previously . In brief, atelocollagen (NMP collagen PS, provided by Nippon Meatpackers, Ibaraki, Japan) was used to make the collagen scaffold.…”

“…This paste‐like collagen fiber suspension was poured into a container and frozen at −10°C. This container was surrounded by an insulation material, and could be cooled only from the bottom . Therefore, this container allowed for the collagen fibers to orient in a direction perpendicular to the bottom.…”

“…In brief, the processing temperature was systematically changed from 120 to 160°C and the processing time was changed from 0 to 28 h as necessary. The pore size of the collagen fiber scaffold within about 5 mm from the cooling surface is too small for cells to infiltrate into the scaffold, and hence only the portion of the scaffold >5 mm from the bottom was used; this pore size ranged from 100 to 300 μm, which is considered to be in the suitable range for cells to infiltrate the scaffold . After cutting into 1 cm × 1 cm × 5 mm sections [Figure (a)], the collagen fiber scaffold was sterilized with ethylene oxide gas before implantation.…”

Non‐woven bilayered biodegradable chitosan‐gelatin‐polylactide scaffold for bioengineering of tracheal epithelium

“…21,22 However, the use of collagen-based scaffolds is hampered by the insufficient mechanical properties of these materials. 23 To tackle these conflicting demands, we have chosen the CGP copolymer combining high mechanical properties and suitability for electrospinning of polylactide 9,24 with biocompatibility, high cell adhesion capacity and antibacterial properties of chitosan. 23 To tackle these conflicting demands, we have chosen the CGP copolymer combining high mechanical properties and suitability for electrospinning of polylactide 9,24 with biocompatibility, high cell adhesion capacity and antibacterial properties of chitosan.…”