Bioactive starch-based scaffolds and human adipose stem cells are a good combination for bone tissue engineering.

Silicon is known to have an influence on calcium phosphate deposition and on the differentiation of bone precursor cells. This study explores the effect of the incorporation of silanol (Si-OH) groups into polymeric scaffolds on the osteogenic differentiation of human adipose stem cells (hASC) cultured under dynamic and static conditions. A blend of corn starch with polycaprolactone (30/70 wt.%, SPCL) was used to produce three-dimensional fibre meshes scaffolds by the wet-spinning technique, and a calcium silicate solution was used as a non-solvent to develop an in situ functionalization with Si-OH groups. In vitro assessment, using hASC, of functionalized and non-functionalized scaffolds was evaluated in either α-MEM or osteogenic medium under static and dynamic conditions (provided by a flow perfusion bioreactor). The functionalized materials, SPCL-Si, exhibit the capacity to sustain cell proliferation and induce their differentiation into the osteogenic lineage. The formation of mineralization nodules was observed in cells cultured on the SPCL-Si materials. Culturing under dynamic conditions using a flow perfusion bioreactor was shown to enhance the hASC proliferation and differentiation and a better distribution of cells within the material. The present work demonstrates the potential of these functionalized materials for future applications in bone tissue engineering. Additionally, these results highlight the simplicity, economic and reliable production process of those materials.

Synergistic antimycobacterial activities of sesquiterpene lactones from Laurus spp.

OBJECTIVES: The aim of this study was to determine the antimycobacterial potential of laurel oil, its fractions and its two sesquiterpene lactones against several mycobacterial strains and clinical isolates, and to establish the possibility of occurrence of some synergistic effects between those lactones using a modification of the fluorometric Alamar Blue microassay (FMABA). METHODS: The in vitro antimycobacterial activity of whole oil and its fractions and pure active compounds were determined by FMABA. A bioassay-guided fractionation of the traditional preparation of laurel oil from Madeira Islands was performed, yielding pure compounds chemically identified by standard procedures. Synergism of pure compounds was established by X/Y quotient analysis adapted to FMABA. RESULTS: Sesquiterpene lactones, costunolide and dehydrocostuslactone, were the compounds responsible for the antimycobacterial activity against Mycobacterium tuberculosis H37Rv with MICs of 6.25 and 12.5 mg/L, respectively. Antimycobacterial activity against drug-resistant M. tuberculosis clinical isolates was better for the mixture than for pure compounds. CONCLUSIONS: Both lactones presented synergistic activity, i.e. analysis of relative fluorescence units presented an X/Y value <0.5 at a concentration of 1/8 MIC of each compound in the combination. Establishment of synergism by FMABA represents another application of the microplate Alamar Blue assay.