Noninvasive cross-sectional observation of three-dimensional cell sheet-tissue-fabrication by optical coherence tomography.

Cell sheet engineering allows investigators/clinicians to prepare cell-dense three-dimensional (3-D) tissues, and various clinical trials with these fabricated tissues have already been performed for regenerating damaged tissues. Cell sheets are easily manipulated and 3-D tissues can be rapidly fabricated by layering the cell sheets. This study used optical coherence tomography (OCT) to noninvasively analyze the following processes: (1) adhesions between layered cell sheets, and (2) the beating and functional interaction of cardiac cell sheet-tissues for fabricating functional thicker 3-D tissues.

Real-time, noninvasive optical coherence tomography of cross-sectional living cell-sheets in vitro and in vivo.

Cell sheet technology has a history of application in regenerating various tissues, having successfully completed several clinical trials using autologous cell sheets. Tomographic analysis of living cell sheets is an important tool in the field of cell sheet-based regenerative medicine and tissue engineering to analyze the inner structure of layered living cells. Optical coherence tomography (OCT) is commonly used in ophthalmology to noninvasively analyze cross-sections of target tissues at high resolution.

Efficient 340-nm light generation by a ridge-type waveguide in a first-order periodically poled MgO:LiNbO3.

Quasi-phase-matched (QPM) UV second-harmonic generation (SHG) in a periodically poled MgO:LiNbO3 waveguide is presented. A ridge-type waveguide with high nonlinearity and strong resistance to photorefractive damage was achieved by use of an ultraprecision machining technique. By use of this waveguide in 1.

Generation of 360-nm ultraviolet light in first-order periodically poled bulk MgO:LiNbO3.

Ultraviolet second-harmonic generation in first-order periodically poled MgO:LiNbO3 is presented. Using a high-voltage multipulse application method, we fabricated a first-order nonlinear grating with a period of 1.8 microm and depth of approximately 150 microm over 10-mm interaction length in a 1-mm-thick MgO:LiNbO3 substrate.