Suchergebnisse

First published online 15 Aug 2014 ; Herein, we evaluate the influence of a PLL–HA bilayer on the surface of silica nanoparticles on their capacity to induce the osteogenic differentiation of human bone marrow stem cells (hBMSCs), as a function of their concentration (50 μg mL−1, 25 μg mL−1 and 12.5 μg mL−1). To this purpose, we synthesized silica nanoparticles (diameter of 250 nm; ζ-potential of −25 mV) that were coated with PLL–HA (diameter of 560 nm; ζ-potential of −35 mV). The cell viability, cell proliferation, protein quantification (i.e. MTS, DNA and ALP, respectively) and gene expression (of osteogenesis-related genes: ALP, osteocalcin, collagen type I, bone sialoprotein, Runx-2, osteopontin and osterix) were monitored, for 21 days. We observed the overexpression of most of the tested osteogenic transcripts in the hBMSCs cultured with SiO2–PLL–HA, at concentrations of 25 μg mL−1 and 12.5 μg mL−1. These results indicate that the proposed nanoparticles temporarily improve the osteogenic differentiation of hBMSCs at low nanoparticle concentrations. ; We acknowledge funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number REGPOT-CT2012-316331-POLARIS. AM acknowledges QREN (project "RL1-ABMR-NORTE-01-0124-FEDER-000016" co-financed by the North Portugal Regional Operational Programme (ON. 2, "O Novo Norte") under the NSRF through the ERDF) for financing this research ...

The effective osteogenic commitment of human bone marrow mesenchymal stem cells (hBMSCs) is critical for bone regenerative therapies. Extracellular vesicles (EVs) derived from hBMSCs have a regenerative potential that has been increasingly recognized. Herein, the osteoinductive potential of osteogenically induced hBMSC-EVs was examined. hBMSCs secreted negatively charged nanosized vesicles (â ¼35 nm) with EV-related surface markers. The yield of EVs over 7 days was dependent on an osteogenic stimulus (standard chemical cocktail or RUNX2 cationic-lipid transfection). These EVs were used to sequentially stimulate homotypic uncommitted cells during 7 days, matching the seeding density of EV parent cells, culture time, and stimuli. Osteogenically committed hBMSC-EVs induced an osteogenic phenotype characterized by marked early induction of BMP2, SP7, SPP1, BGLAP/IBSP, and alkaline phosphatase. Both EV groups outperformed the currently used osteoinductive strategies. These data show that naturally secreted EVs can guide the osteogenic commitment of hBMSCs in the absence of other chemical or genetic osteoinductors. ; The authors thank the financial support of QREN (RL1-ABMRNORTE-01-0124-FEDER-000016 and RL3–TECT–NORTE-01-0124- FEDER-000020) co-financed by North Portugal Regional Operational Program (ON.2–O Novo Norte), under the NSRF, through the ERDF; the European Union's Seventh Framework Program (FP7/2007–2013), Grant No. REGPOT-CT2012-316331- POLARIS; and the laboratory assistance of Elsa Ribeiro, Magda Graça, and Sónia ...

Melt blends of chitosan and biodegradable aliphatic polyester have been physically and biologically studied, presenting great potential for biomedical applications. Structurally, poly(butylene succinate)–chitosan (PBS/Cht) composite scaffolds are covered by a thin PBS layer, preventing the desired interaction of cells/tissues with the chitosan particules. In the present work, a selective and controlled ablation of this skin layer was induced by UV laser processing. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF–SIMS) data demonstrated an increment of chitosan components and others resulting from the laser ablation process. The biological activity (i.e. cell viability and proliferation) on the inner regions of the composite scaffolds is not significantly different from those of the external layer, despite the observed differences in surface roughness (determined by interferometric optical profilometry) and wettability (water contact angle). However, the morphology of human osteoblastic cells was found to be considerably different in the case of laser-processed samples, since the cells tend to aggregate in multilayer columnar structures, preferring the PBS surface and avoiding the chitosan-rich areas. Thus, UV laser ablation can be considered a model technique for the physical surface modification of biomaterials without detrimental effects on cellular activity. ; This work was partially supported by the European Union Integrated Project GENOSTEM (LSH-STREP-CT-2003-503161), the European Union Network of Excellence EXPERTISSUES (NMP3-CT-2004-500283), the Interreg III Project PROTEUS (SP1P151/03) and Xunta de Galicia (Consolidacion 2006/12). The Portuguese Foundation for Science and Technology is also acknowledged for a PhD grant to A.M. (SFRH/BD/24382/2005). The authors wish to thank C. Serra from CACTI of the University of Vigo for the XPS and ToF-SIMS ...

There is an urgent need for antitumor bioactive agents with minimal or no side effects over normal adjacent cells. Fucoidan is a marine-origin polymer with known antitumor activity. However, there are still some concerns about its application due to the inconsistent experimental results, specifically its toxicity over normal cells and the mechanism behind its action. Herein, three fucoidan extracts (FEs) have been tested over normal and breast cancer cell lines. From cytotoxicity results, only one of the extracts shows selective antitumor behavior (at 0.2 mg mLâ 1), despite similarities in sulfation degree and carbohydrates composition. Although the three FEs present different molecular weights, depolymerization of selected samples discarded Mw as the key factor in the antitumor activity. Significant differences in sulfates position and branching are observed, presenting FE 2 the higher branching degree. Based on all these experimental data, it is believed that these last two properties are the ones that influence the cytotoxic effects of fucoidan extracts. ; The authors would like to thank the funding from projects 0687_NOVOMAR_1_P, cofunded by INTERREG 2007-2013/POCTEP, CarbPol_u_Algae (EXPL/MAR-BIO/0165/2013), and IF/00376/2014/CP1212/CT0015, funded by the Portuguese Foundation for Science and Technology, FCT, and ComplexiTE (ERC-2012-ADG 20120216-321266), funded by the European Research Council under the European Union's Seventh Framework Programme for Research and Development. The authors would also like to thank FCT, Portugal, for the scholarship of A.S.F. (SFRH/BD/102471/2014), fellowship of C.N. (SFRH/BPD/100627/2014), Investigator grants of A.M. (IF/00376/2014), R.N.-C. (IF/00373/2014), and I.P. (IF/00032/2013) and the financial support to CICECO-Aveiro Institute of Materials (POCI-01-0145-FEDER-007679, FCT UID/CTM/50011/2013) and OOPNA (UID/OUI/00062/2013), through national founds and cofinanced by the FEDER, within the PT2020 Partnership ...