Optimum sterilization methods of biocompatible hybrid material for artificial organs

We previously reported the development of a new hybrid medical material comprising bio-based materials with high biocompatibility and artificial materials with characteristics of excellent strength and processability. This material shows sufficient biocompatibility and excellent stability in vivo. Moreover, when applied to the surface of an implantable sensor, the biological reaction on the sensor function surface can be well controlled. For commercialization and widespread use of hybrid materials with such superior properties, sterilization and storage are critical considerations, given that hybrid materials must be processed outside the body prior to application as medical materials in vivo, thus posing a risk of contamination despite best efforts. There-fore, the aim of the present study was to establish an optimal sterilization method that will not impair the bio-compatibility of the hybrid material. Toward this end, we tested six sterilization methods for the hybrid materi-al: autoclave (121°C, 20 min), dry heat (160°C, 120 min), ethylene oxide gas (37°C, 120 min), hydrogen peroxide plasma (45°C, 45 min), and gamma ray (25 kGy) with and without lyophilization. After sterilization, the material was cultured with vascular endothelial cells to evaluate the engraftment rate, and was observed with light and scanning electron microscopy to determine shape and structure changes. The results demonstrated that gamma sterilization without lyophilization was the best sterilization method for this material, which preserved the collagen network and showed no change in number of adhered vascular endothelial cells compared to the pre-sterilized material. These findings are useful to promote the commercialization of this hybrid material with combined advantages of synthetic and bio-based materials for widespread clinical application in the engineering of artificial organs.