Chunfang Zhou

In vivo Enhancement in Bioavailability of Atazanavir in the Presence of Proton-Pump Inhibitors using Mesoporous Materials

In vivo Enhancement in Bioavailability of Atazanavir in the Presence of Proton-Pump Inhibitors using Mesoporous Materials

Delivery of Differentiation Factors by Mesoporous Silica Particles Assists Advanced Differentiation of Transplanted Murine Embryonic Stem Cells

Stem cell transplantation holds great hope for the replacement of damaged cells in the nervous system. However, poor long‐term survival after transplantation and insufficiently robust differentiation of stem cells into specialized cell types in vivo remain major obstacles for clinical application. Here, we report the development of a novel technological approach for the local delivery of exogenous trophic factor mimetics to transplanted cells using specifically designed silica nanoporous particles. We demonstrated that delivering Cintrofin and Gliafin, established peptide mimetics of the ciliary neurotrophic factor and glial cell line‐derived neurotrophic factor, respectively, with these particles enabled not only robust functional differentiation of motor neurons from transplanted embryonic stem cells but also their long‐term survival in vivo. We propose that the delivery of growth factors by mesoporous nanoparticles is a potentially versatile and widely applicable strategy for efficient differentiation and functional integration of stem cell derivatives upon transplantation.

Bicontinuous Cubic Mesoporous Materials with Biphasic Structures

The replication of amphiphilic systems within an inorganic silica matrix allows the study of the fundamental properties of mesostructural changes, that is, kinetic and structural parameters. Herein we report a detailed study of the transition between cubic bicontinuous mesostructure with space groups Ia ̅3d and Pn ̅3m symmetry, which are associated with the minimal G and D surfaces, respectively. The transition may be induced through micellar swelling of the anionic amphiphilic surfactant N-lauroyl alanine by trimethylbenzene. Rich kinetic behaviour is observed and has been exploited to prepare particles with biphasic structures. Transmission electron microscopy evidence indicates that there is epitaxial growth from one mesostructure to the other involving the [111] and [110] orientations of the Ia ̅3d and Pn ̅3m symmetry structures, respectively. From kinetic studies, we show that the formation of the Ia ̅3d mesophase is preceded by a hexagonal phase (plane group p6mm) and an epitaxial relationship has been observed involving the sixfold or ̅3 axis orientations of both structures. Our data suggests that the Pn ̅3m mesostructure is kinetically stable at low temperatures whereas the Ia ̅3d mesostructure is the more stable structure after prolonged periods of hydrothermal treatment. We present evidence from transmission electron microscopy and small-angle X-ray diffractograms and also electron crystallography modelling of the unit cells at particular points in the structural change.

In vitro generation of motor neuron precursors from mouse embryonic stem cells using mesoporous nanoparticles

AIM Stem cell-derived motor neurons (MNs) are utilized to develop replacement strategies for spinal cord disorders. Differentiation of embryonic stem cells into MN precursors involves factors and their repeated administration. We investigated if delivery of factors loaded into mesoporous nanoparticles could be effective for stem cell differentiation in vitro. MATERIALS & METHODS We used a mouse embryonic stem cell line expressing green fluorescent protein under the promoter for the MN-specific gene Hb9 to visualize the level of MN differentiation. The differentiation of stem cells was evaluated by expression of MN-specific transcription factors monitored by quantitative real-time PCR reactions and immunocytochemistry. RESULTS Mesoporous nanoparticles have strong affiliation to the embryoid bodies, penetrate inside the embryoid bodies and come in contact with differentiating cells. CONCLUSION Repeated administration of soluble factors into a culture medium can be avoided due to a sustained release effect using mesoporous silica.

Morphological properties of nanoporous folic acid materials and in vitro assessment of their biocompatibility

BACKGROUND Mesoporous silica-based particles are of potential interest for the development of novel therapeutic targeted delivery vehicles. Their ability to load and release large quantities of active pharmaceutical products with varying properties, combining controlled and targeted release functions make them unique amongst nanotechnology-based carrier systems. MATERIALS & METHODS In this study, nanoporous folic acid-templated materials (NFM-1) were prepared and the synthetic strategies for the control of textural and morphology properties of NFM-1 are described. The potential biocompatibility of NFM-1 particles with different morphology (gyroid shaped, fibers and rod-shaped) was assessed using a panel of human cell lines. RESULTS The results reveal that NFM-1 morphology has an impact on cell viability such that particles showing higher aspect ratios possess increased cytotoxicity. CONCLUSION These studies provide useful information for the development of novel mesoporous materials for biomedical applications, including cell-specific drug delivery.

The effect of mesoporous silica particles on stem cell differentiation

Mesoporous silica particles (MSPs) are characterized by ordered porosity, sharp pore size distributions, high internal surface areas, and large pore volumes.1,2 Control over these structural parameters makes them an ideal candidate for drug encapsulation, perfectly suited to uptake and carry large amounts of drugs that then get released with constant concentration.3–5 The release of the actives can be diffusion controlled or may be triggered by a change in media temperature or pH.6 Creation of simultaneous release profiles is possible by using different pore structures (e. g., 2D hexagonal and 3D cubic) that enable a continuous discharge of a fine tuned mixture of active drugs over a given period of time.