Epirubicin-loaded superparamagnetic iron-oxide nanoparticles for transdermal delivery: cancer therapy by circumventing the skin barrier.

The transdermal administration of chemotherapeutic agents is a persistent challenge for tumor treatments. A model anticancer agent, epirubicin (EPI), is attached to functionalized superparamagnetic iron-oxide nanoparticles (SPION). The covalent modification of the SPION results in EPI-SPION, a potential drug delivery vector that uses magnetism for the targeted transdermal chemotherapy of skin tumors. The spherical EPI-SPION composite exhibits excellent magnetic responsiveness with a saturation magnetization intensity of 77.8 emu g(-1) . They feature specific pH-sensitive drug release, targeting the acidic microenvironment typical in common tumor tissues or endosomes/lysosomes. Cellular uptake studies using human keratinocyte HaCaT cells and melanoma WM266 cells demonstrate that SPION have good biocompatibility. After conjugation with EPI, the nanoparticles can inhibit WM266 cell proliferation; its inhibitory effect on tumor proliferation is determined to be dose-dependent. In vitro transdermal studies demonstrate that the EPI-SPION composites can penetrate deep inside the skin driven by an external magnetic field. The magnetic-field-assisted SPION transdermal vector can circumvent the stratum corneum via follicular pathways. The study indicates the potential of a SPION-based vector for feasible transdermal therapy of skin cancer.

Different effects of nanophase and conventional hydroxyapatite thin films on attachment, proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells.

UNLABELLED: It is suggested that nanophase hydroxyapatite (nHAP) might have advantages over conventional hydroxyapatite (cHAP) as a biomaterial for bone regeneration. To be a satisfactory candidate for bone tissue engineering, it is important to support the growth and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). The purpose of this study is to determine whether nHAP as cell growth substrata could give better support for attachment, proliferation and osteogenic differentiation of BMSCs than cHAP. MATERIALS AND METHODS: nHAP and cHAP films were prepared as the substrata for the cell growth. BMSCs obtained from rabbit were seeded on the films. Attachment, proliferation and osteogenic differentiation of BMSCs on the two kinds of films were evaluated. RESULTS: Cell attachment ratio on nHAP films was significantly higher than that on cHAP films. Doubling time on nHAP films was significantly shorter than that on cHAP films. Amount of total proteins detected from cells cultured on nHAP films was significantly higher than that on cHAP films. However, alkaline phosphatase activity and osteocalcin content of the two groups showed no significant difference. CONCLUSIONS: nHAP films favored cell attachment and proliferation but not osteogenic differentiation of BMSCs compared with cHAP films.

The effect of extracellular calcium and inorganic phosphate on the growth and osteogenic differentiation of mesenchymal stem cells in vitro: implication for bone tissue engineering.

The aim of this study is to demonstrate the effect of extracellular calcium ion (Ca2+) and inorganic phosphate (Pi) concentrations on the growth and differentiation of bone-marrow-derived mesenchymal stem cells (MSCs), which is essential to understand the interaction between calcium phosphate ceramic (CPC) scaffolds and seeded cells during the construction of tissue-engineered bones. MSCs were separated from rabbits and cultured in media with different concentrations of Ca2+ and Pi supplements. Their proliferation, apoptosis, mineralization and osteogenic differentiation were determined by the MTT assay, TUNEL assay, Vonkossa stain and RT-PCR examination. A two-way ANOVA calculation with comparisons of estimated marginal means by LSD was used for statistical analysis. Results showed that the optimal extracellular Ca2+ and Pi concentrations for the cells to proliferate and differentiate were 1.8 mM and 0.09 mM, respectively, which are the concentrations supplied in many commonly used culture media such as DMEM and alpha-MEM. Cell proliferation and differentiation decreased significantly with greater or lower concentrations of the Pi supplement. Greater Pi concentrations also led to significant cell apoptosis. Greater Ca2+ concentrations did not change cell proliferation but significantly inhibited cell differentiation. In addition, greater Ca2+ concentrations could significantly enhance cell mineralization. In conclusion, extracellular Ca2+ and Pi significantly influence the growth and osteogenic differentiation of MSCs. It is important to take the cellular effect of Ca2+ and Pi into consideration when designing or constructing scaffolds for bone tissue engineering with CPC.