Controlled Nanoscale Topographies for Osteogenic Differentiation of Mesenchymal Stem Cells.

Nanotopography with length scales of the order of extracellular matrix elements offers the possibility of regulating cell behavior. Investigation of the impact of nanotopography on cell response has been limited by the inability to precisely control geometries, especially at high spatial resolutions and across practically large areas. In this paper, we demonstrate well-controlled and periodic nanopillar arrays of silicon and investigate their impact on osteogenic differentiation of human mesenchymal stem cells (hMSCs). Silicon nanopillar arrays with critical dimensions in the range of 40-200 nm, exhibiting standard deviations below 15% across full wafers, were realized using the self-assembly of block copolymer colloids. Immunofluorescence and quantitative polymerase chain reaction measurements reveal clear dependence of osteogenic differentiation of hMSCs on the diameter and periodicity of the arrays. Further, the differentiation of hMSCs was found to be dependent on the age of the donor. While osteoblastic differentiation was found to be promoted by the pillars with larger diameters and heights independent of donor age, they were found to be different for different spacings. Pillar arrays with smaller pitch promoted differentiation from a young donor, while a larger spacing promoted those of an old donor. These findings can contribute for the development of personalized treatments of bone diseases, namely, novel implant nanostructuring depending on patient age.

Study by ESI-FTICRMS and ESI-FTICRMS(n) of zinc and cadmium thiophenolate complexes used as precursors for the synthesis of II-VI nanosemiconductors.

[M(4)(SC(6)H(5))(10)][(CH(3))N](2), [M(10)L(4)(SC(6)H(5))(16)][(CH(3))N](4) and [Cd(17)S(4)(SC(6)H(5))(28)][(CH(3))N](2)(M = Cd or Zn, and L = S or Se) zinc and cadmium thiophenolates have been studied by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (ESI-FTICRMS) and tandem ESI-FTICRMS (ESI-FTICRMS(n)). ESI-FTICRMS demonstrated its ability to characterize and study such compounds, which may be used as precursors of II-VI nanomaterials. The obtained mass spectrum has been found to be highly relevant of the investigated thiophenolate and the fragmentation behavior of some of the detected ions is indicative of its stability. More specifically, it has been demonstrated that ESI in-source activation or fragmentation experiments conducted in the Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) cell induced the formation of a very stable entity, which corresponds to the general formula M(4)L(4) (M = Zn or Cd and L = S or Se). The elimination of SC(6)H(5)(-) and/or M(SC(6)H(5))(2) moieties by various activation processes from the studied thiophenolates led systematically to this structure.