Collagen films

Polymers. In combination with various metal salts, sorbitol is used as a stabilizer against beat and light in poly(vinyl chloride) (qv) resins and, with a phenolic antioxidant, as a stabilizer in uncured styrene—butadiene mbber (qv) compositions and in polyolefins (see He AT STABILIZERS Olefin polymers Rubber compounding). Heat-sealable films are prepared from a dispersion of sorbitol and starch in water (255). Incorporation of sorbitol in collagen films gready restricts their permeability to carbon dioxide (256). 

White, M. J., Kohno, I., Rubin, A. I., Stenzel, . H., and Miyata, T. (1973). Collagen films Effect of cross-linking on physical and biological properties. Biomater. Med. Devices Artif. Organs 1, 703-715. 

Tiller JC, Bonner G, Pan L-C et al. (2001) Improving biomaterial properties of collagen films by chemical modification. Biotechnol Bioeng 73 246-252... 

Collagen films formed by reticulations of amine and carboxyl groups gelatin-based films flexible, clear, widi good oxygen barrier properties, but poor moisture resistance classical formulations 20-30% gelatin, 10-30% plasticizer mid water. 

Enzymes, such as creatine kinase, have been grafted on to collagen films by using water soluble carbodiimides. Porcine intestinal collagen has been crosslinked with EDC in acetone to provide a remodelable scaffold. EDC crosslinking of collagen/elastin matrices is also used to prepare fiat scaffolds. ... 

A variety of methods for preparing collagen films from enzyme-solubilized, monomeric collagen with diflFerent surface structures were evaluated. Our initial interest was to determine the effects of various preparative techniques on the in vivo behavior of the films. 

Dialdehyde Starch Collagen Fiber—20% Collagen Films Soluble Collagen... 

Figure I. Control (not crosslinked) collagen film removed after 7 days subcutaneous implantation in rabbits. XI28...

All of the crosdinked implants lasted for at least 60 days. At this time, a few of the enzyme-solubilized collagen films crosslinked with either glutaraldehyde or dialdehyde starch appeared to be thinner. Some of the films crosslinked with glutaraldehyde appeared to be somewhat thinner after 90 days, although most were intact. 

Figure 3 is a method II enzyme-solubilized collagen film crosslinked with glutaraldehyde and implanted subcutaneously. It was unchanged after 90 days. 

Figure 4, Method 11 glutaraldehyde crosslinked composite collagen fiber-soluble collagen film removed after 90 days intramuscular implantation in...

These studies provide a base for further development of collagen materials for specific biomaterial applications. Further studies are being directed to the effect of collagen film on blood in terms of platelet and white cell adhesion, protein absorption, and thrombogenicity. 

Figure 2. Plot of contact angle data for rat skin collagen films at 50% relative humidity and when completely water swollen...

Figure 4. Internal reflection IR spectra of the surface zones of cold water cast rat skin collagen films (top) and hot water cast (i.e., gelatinized) films from the same original sample (bottom)...

In one series of experiments, collagen films (0.0013 cm and 0.005 cm thick) made from collagen fibrils of about 99% purity were substituted for the collagen powders in the standard grafting experiment. Although it was not possible to measure weight increase in the thinner film specimens, the IR spectra of the treated and solvent-extracted films indicated that polymer was probably grafted onto the substrate. 

Maeda M, Kadota K, Kajihara M, et al. (2001). Sustained release of human growth hormone (hGH) from collagen film and evaluation of effect on wound healing in db/db mice./. Control. Rel. 77 261-272. 

Many in vitro models have also been developed to assess skin irritation. Many of these involve the swelling of human or animal skin [177], the swelling of a collagen film [178], water vapor loss [179], and squamometry [180]. All of these methods have shown some degree of correlation to skin irritation on humans and animals. The results from many of these tests have been considered in the next section to provide some rules of thumb to describe and compare the relationships of skin irritation potential for various surfactants. 

Collins, R.L., Christiansen, D., Zazanis, G.A., and Silver, EH. 1991. Use of collagen film as a dural substitute Preliminary animal studies. J. Biomed. Mater. Res. 25 267-276. 

Film preparation. Collagen was dispersed in HCl aqueous solution of pH 3.0 to have a concentration of 1 wt%. The dispersion was cast on a Petri dish and flowed to dry at atmospheric pressure and 25°C to obtain collagen film of about 0.1mm thickness. Gelatin was dissolved in distilled water of pH 5.5 at 40°C to have a concentration of 10 wt%. For the film preparation, the solution was cast on a Petri dish and allowed to dry in air at 25°C to obtain gelatin film of about 0.3mm thickness. 

Fig.2 Effect of the GA concentration on the mechanical properties of collagen films crosslinked with GA in PBS (pH 7.4) at 4°C for 24hr.

Fig.9 In vitro degradation of various crosslinked collagen films upon hydrolysis in 40units/ml collagenase solution at 37°C and pH 7.4.

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