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Naotaro Akiyama,1 Tomomi Yamamoto-Fukuda,1,2 Haruo Takahashi,1 Takehiko Koji21Department of Otolaryngology – Head and Neck Surgery, 2Department of Histology and Cell Biology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, JapanAbstract: Middle-ear mucosa maintains middle-ear pressure. However, the majority of surgical cases exhibit inadequate middle-ear mucosal regeneration, and mucosal transplantation is necessary in such cases. The aim of the present study was to assess the feasibility of transplantation of isolated mucosal cells encapsulated within synthetic self-assembling peptide nanofiber scaffolds using PuraMatrix, which has been successfully used as scaffolding in tissue engineering, for the repair of damaged middle ear. Middle-ear bullae with mucosa were removed from Sprague Dawley (SD) transgenic rats, transfected with enhanced green fluorescent protein (EGFP) transgene and excised into small pieces, then cultured up to the third passage. After surgical elimination of middle-ear mucosa in SD recipient rats, donor cells were encapsulated within PuraMatrix and transplanted into these immunosuppressed rats. Primary cultured cells were positive for pancytokeratin but not for vimentin, and retained the character of middle-ear epithelial cells. A high proportion of EGFP-expressing cells were found in the recipient middle ear after transplantation with PuraMatrix, but not without PuraMatrix. These cells retained normal morphology and function, as confirmed by histological examination, immunohistochemistry, and electron microscopy, and multiplied to form new epithelial and subepithelial layers together with basement membrane. The present study demonstrated the feasibility of transplantation of cultured middle-ear mucosal epithelial cells encapsulated within PuraMatrix for regeneration of surgically eliminated mucosa of the middle ear in SD rats.Keywords: nanofiber, synthetic self-assembling peptide scaffolds, regeneration, middle-ear mucosa, in situ tissue engineering

When electrons from a plasma enter a water surface, they collide with the water molecules and lose their energy, eventually becoming hydrated electrons, which are an important species for radical formation in liquid water. Although gas discharge plasmas in contact with water are an easy source of hydrated electrons, their production processes are not clearly understood. In this study, Monte Carlo simulations of electrons in liquid water were performed to investigate the production of a hydrated electron and radical species by low-energy electron irradiation of the water surface from an atmospheric-pressure plasma. The incident electrons were assumed to have a Maxwellian energy distribution with mean electron energy ranging from 1 to 10 eV. The production of hydrated electrons by electron irradiation of 3 eV reached a peak near the gas–liquid interface, and the electrons spread to a depth of approximately 17 nm. OH and H are also generated near the water surface. [ABSTRACT FROM AUTHOR]