Far-infrared ray (FIR) is electromagnetic wave between 4 and 1000 μm. FIR causes heating, but how it affects cells is not well understood. In this study, we developed a culture incubator that can continuously irradiate cells with FIR and examined the effects of FIR on five human cancer cell lines, namely A431 (vulva), A549 (lung), HSC3 (tongue), MCF7 (breast) and Sa3 (gingiva). We found that FIR inhibits cell proliferation and induces cell hypertrophy without apoptosis in A549, HSC3 and Sa3 cells. Flow cytometry revealed that the inhibition of proliferation was due to G2/M arrest. Contrary, FIR did not inhibit cell proliferation and cause cell hypertrophy in A431 or MCF7 cells. Microarray analysis revealed that FIR suppressed the expression of cell proliferation-related and stress-responsive genes in FIR-

Far infrared ray (FIR) energy radiated by the natural ceramics (Rhyolite) cooled FIR ceramics activates water molecules and blood circulation to stimulate skin and other tissues. The aim of our study is to make clear whether the FIR ceramics radiating FIR energy affect or not on the new bone formation in vivo and in vitro. Methods: MC3T3-E1 cells were cultured in FIR CO 2 incubator. The cell proliferation and the gene expression were analyzed by using WST-8 assay kit, RT-PCR and micro array analysis. The enzyme activities were analyzed by using the api R ZYM kit. Furthermore, titanium and natural FIR ceramics compounds were implanted under the periosteium of rat skull bone by injection method. Four weeks later, the samples were examined by the light microscope and micro CT analyses. Results: Proliferation of MC3T3-E1 cell was and DNA concentrations were inhibited by FIR energy radiation. The ALP activities were accelerated and the area of calcification nodules increased on 4 weeks. The RT-PCR data showed that the gene Runx2, Osterix, BSP, OCN, Col1a1 and OPN expression of MC3T3-E1 osteoblast like cells was activated. Bone mineral density (BMD mg/cm²) of implanted sites of T50-F50, T25-F75 and F100 groups was significantly enhanced after 4 weeks compared with control groups. This data shows FIR energy radiation by the natural FIR ceramics promoted bone-forming activity of osteoblasts. Significance: This study suggested that new bioactive ceramics such us natural FIR ceramics was useful for some clinically applications to repair bone defects for example of dental implant surgery.