A collagen vitrigel membrane (CVM) is composed of high-density collagen fibril networks, so there are plenty of interstices from a few ten to a few hundred nanometers. The CVM functions as not only a scaffold of anchorage-dependent cells but also a semipermeable membrane for exchanging chemical substances without microbial contamination. Here, I propose a novel concept for cell culture technology using two different types of the CVM-fixed frame devices for enclosing cells that can facilitate the handling of cells in culture. The ring-shaped device was prepared by glueing dried CVMs (i.e. collagen xerogel membranes, CXMs) on the both sides of a ring-shaped plastic frame with a through hole. The CXM is converted to a CVM by rehydration. HepG2 cells suspended in a culture medium was seeded into the ring-shaped device from its through hole and plugging it. The cells enclosed in the device could be cultured for a long period with excellent cell viability by merely changing its outside culture medium. Also, most of the cells were alive after preserving the device for two days in the culture medium at 25^oC. The tubular screw-shaped device composed of a female screw part and a male screw part was prepared by glueing a CXM on the head of each tubular screw-shaped plastic frame and attaching three legs for self-standing on the CXM outside of female screw. The cells seeded in the female screw part were easily enclosed by fitting the male screw part. These findings suggest that the cell enclosure devices with CVMs would be useful for the non-freeze transport of ready-to-use cells and culture models in near future.

Little is known about the influence of the phototoxicity of dental materials. Light-cured composite resin is polymerized by intense light irradiation in the oral cavity, although it is temporary. There has been no report on the biological influence of intense light irradiation on oral cavity tissue. We previously confirmed that camphorquinone (CQ) contained in light-cured composite resin for dental use as a photosensitizer decreased the cell viability in a light-irradiated group compared with that in a non-irradiated group within a concentration range from 0.313 to 2.5 mg/mL using 3T3 cells specified in the OECD phototoxicity guidelines. In this study, we investigated the influence of light irradiation in actual light-cured composite resin mixed with Bis-GMA contained as a base monomer, not the influence of CQ alone, on the influence of light irradiation on cell viability. It was confirmed that similarly to CQ alone, the cell viability decreased in the state mixed with Bis-GMA.

Cells derived from animals other than humans are used in the cytotoxicity screening tests of many pharmaceuticals and quasi-drugs used in humans. FIBLAST^® spray contains recombinant human FGF2 protein as a main ingredient for which data concerning the proliferation of various cells are available. We investigated the influence of this product on the cell viability of mouse-derived Balb/c 3T3 cells. Under the condition of the addition of FIBLAST^® solution, unlike human-derived cells, the viability decreased in about half of the cells, clarifying the cytotoxicity of the product, and this was not dependent on the serum concentration of the culture medium. It was suggested that a species difference between humans and animals influenced the result. However, the influence of additives is also considered because many additives are mixed in FIBLAST^® spray, so it was not possible to conclude that the test result was due to the influence of a species difference. It may be necessary to compare the result with the influence of trafermin alone in the future.