title: In vivo study of dendronlike nanoparticles for stem cells "tune-up": from nano to tissues.
abstract: The control of stem cell differentiation to obtain osteoblasts in vivo is still regarded as a challenge in stem-cell-based and bone-tissue engineering strategies. Biodegradable dexamethasone-loaded dendron-like nanoparticles (NPs) of carboxymethylchitosan/poly(amidoamine) dendrimer have been proposed as intracellular drug-delivery systems of bioactive molecules. In this study, combination of nanotechnology, stem-cell engineering and tissue engineering is proposed in pre-programming the fate of rat bone marrow stromal cells (RBMSCs) towards osteoblasts cells and development of new bone tissue, in vivo. This work demonstrated that the developed NPs were able to be taken up by RBMSCs, and exhibited a noncytotoxic behavior in vitro. The performance of the developed dendronlike NP system for the intracellular delivery of dexamethasone was investigated by seeding the engineered RBMSCs onto starch-polycaprolactone scaffolds ex vivo, and implanting subcutaneously in the back of Fischer 344/N rats (Syngeneic), in the absence of the typical osteogenic supplements. Favorable results were observed in vivo, thus suggesting that stem cell "tune-up" strategy can open up a new regenerative strategy for bone-tissue engineering.
  
  
  BACKGROUND
  In this study, a combination of nanotechnology, stem-cell engineering and tissue engineering is proposed in pre-programming the fate of rat bone marrow stromal cells (RBMSCs) towards osteoblasts cells and development of new bone tissue in vivo.
authors.affiliation: Biomaterials, Biodegradables and Biomimetics Research Group, Department of Polymer Engineering, University of Minho, Headquarters of European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal.
authors.forename: Joaquim M
authors.initials: JM
authors.lastname: Oliveira
authors.forename: Rui A
authors.initials: RA
authors.lastname: Sousa
authors.forename: Patricia B
authors.initials: PB
authors.lastname: Malafaya
authors.forename: Simone S
authors.initials: SS
authors.lastname: Silva
authors.forename: Noriko
authors.initials: N
authors.lastname: Kotobuki
authors.forename: Motohiro
authors.initials: M
authors.lastname: Hirose
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohgushi
authors.forename: João F
authors.initials: JF
authors.lastname: Mano
authors.forename: Rui L
authors.initials: RL
authors.lastname: Reis
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D001854:Bone Marrow Cells / Q000166:cytology*; D016026:Bone Marrow Transplantation; D001842:Bone and Bones / Q000166:cytology; D048271:Chitosan / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry; D003907:Dexamethasone / Q000008:administration & dosage*; D008297:Male; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology*; D010012:Osteogenesis; D051381:Rats; D011916:Rats, Inbred F344; D017154:Stromal Cells / Q000166:cytology / Q000637:transplantation; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000893:Anti-Inflammatory Agents; D050091:Dendrimers; C104700:PAMAM Starburst; C426873:mono-N-carboxymethylchitosan; D003907:Dexamethasone; D048271:Chitosan