Differentiation of stem cells from the apical papilla into osteoblasts by the elastic modulus of porous silk fibroin scaffolds.

In addition to traditional approach for differentiation (biochemical factors), physical properties (elastic modulus) of the matrix will be becoming an important factor in differentiation of stem cells into different lineages. The porous scaffolds were prepared from the silk fibroin solutions 4%, 5%, 6%, 7% and 8.4% weight per volume (w/v) by freeze drying which produced scaffolds with the minimal changes in the pore size (96-160 μm) but with a ≈ 8-fold range of modulus (16 -131 kPa) in the wet condition.

Evaluation of Novel Mouse-Specific Germ Cell Gene Expression in Embryonic Stem Cell-Derived Germ Cell-Like Cells In Vitro with Retinoic Acid Treatment.

We designed a study to induce differentiation of Oct4-GFP (expression of Green Fluorescent Protein of oct4) embryonic stem cells (ESCs) by embryoid body (EB) culture system into germ cells (GCs) using retinoic acid (RA) and evaluated the expression level of (Fkbp6, Mov10l1, 4930432K21Rik, and Tex13) in differentiated cells. The expression levels of four GC-related genes, Oct4, Mvh, Scp3, and Stra8, was determined by quantitative real-time polymerase chain reaction (q-RT-PCR). Immunostaining and flow cytometry were used as additional tests to confirm q-RT-PCR findings.

Auto-fluorescence of a silk fibroin-based scaffold and its interference with fluorophores in labeled cells.

Silk fibroin is increasingly emerging as an important biomaterial for tissue engineering applications. The ability to fluorescently image silk matrices under a microscope would be helpful in differentiating embedded labeled cells from background signal, critical for the study of silk-based engineered tissues. In this study, we fabricated a scaffold using freeze drying and confirmed its structure by X-ray diffraction and Fourier transform infrared spectroscopy.

Impact of pre-incubation time of silk fibroin scaffolds in culture medium on cell proliferation and attachment.

Cell behaviours such as proliferation and attachment can be affected by the length of pre-incubation period of the scaffolds in the culture medium for long term. The aim of this study was to investigate the long term pre-incubation of 3D silk fibroin scaffolds in complete culture medium on cell attachment and proliferation. After the preparation of silk fibroin scaffolds by the technique of freeze drying, the scaffolds were pre-incubated in complete culture medium for 2 d, 6 d or 10 d before apical papilla stem cells (SCAP) seeding.