Abstract: Abstract: Objective To investigate a highly effective, non-integrative and feeder-free reprogramming technique to derive induced pluripotent stem cells (iPSCs) to provide safe stem cells sources for dental tissue regeneration. Methods Human stem cells from apical papilla (SCAP) were primarily cultured and induced into iPSCs on human recombinant vitronectin with Simplicon RNA reprogramming kit. Specific pluripotency markers were detected by immunofluorescence staining. Teratoma was formed to examine the pluripotency of differentiation in vivo. Total RNA of iPSCs was isolated and RT-PCR was carried out to verify the loss of exogenous reprogramming factors. Reprogramming efficiency of SCAP-iPSCs was calculated. Results Human SCAP-iPSCs exhibited classical ES-like morphology and positively immunostaining for specific markers Oct4, Nanog, Sox2 and SSEA-4. Teratoma was formed 6 weeks after injecting iPSCs into SCID mice and HE staining revealed the cell types of all three germ layers: ectoderm, endoderm and mesoderm. RT-PCR results suggested hSCAP-iPSCs expressed specific multipotent markers and no more exogenous reprogramming factors. The reprogramming efficiency of hSCAP-iPSCs was 0.17-0.20%. Conclusions HSCAP-iPSCs derived with highly reprogramming efficiency and safety is the optimal stem cell source for dental tissue regeneration.

Key words: human stem cells from apical papilla, RNA, reprogramming, induced pluripotent stem cells