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North Hills, CA, United States

Dai J.,Auburn University | Yang X.,Auburn University | Yang X.,CA Technologies | Hamon M.,Renal Regeneration Laboratory | And 2 more authors.
Chemical Engineering Journal | Year: 2015

Controlling the particle size of semiconductors can alter their optical and electronic properties for many applications. Semiconductor nanoparticles with controlled size can be synthesized using the colloidal chemical method. In this study, we used the aqueous colloidal method to synthesize CdS nanoparticles in picoliter droplets generated by a microfluidic device. The microfluidic device used two mechanical cutting valves to generate two different droplets containing precursors (aqueous solution of cadmium chloride (CdCl2) and sodium sulfide (Na2S)). The fusion of these two droplets yielded CdS nanoparticles whose sizes were controlled by 3-Mercaptopropionic acid (MPA), a particle growth inhibitor and stabilizer. We synthesized CdS nanoparticles with narrow size distribution and investigated the effects of precursor concentration and S2-:Cd2+ molar ratio on particle growth. This microfluidic method is capable of easily tuning the reagent concentrations to synthesize nanoparticles in a highly controlled manner. © 2015 Elsevier B.V.

Rak-Raszewska A.,University of Oulu | Hauser P.V.,Renal Regeneration Laboratory | Hauser P.V.,University of California at Los Angeles | Vainio S.,University of Oulu
Stem Cells International | Year: 2015

When Clifford Grobstein set out to study the inductive interaction between tissues in the developing embryo, he developed a method that remained important for the study of renal development until now. From the late 1950s on, in vitro cultivation of the metanephric kidney became a standard method. It provided an artificial environment that served as an open platform to study organogenesis. This review provides an introduction to the technique of organ culture, describes how the Grobstein assay and its variants have been used to study aspects of mesenchymal induction, and describes the search for natural and chemical inducers of the metanephric mesenchyme. The review also focuses on renal development, starting with ectopic budding of the ureteric bud, ureteric bud branching, and the generation of the nephron and presents the search for stem cells and renal progenitor cells that contribute to specific structures and tissues during renal development. It also presents the current use of Grobstein assay and its modifications in regenerative medicine and tissue engineering today. Together, this review highlights the importance of ex vivo kidney studies as a way to acquire new knowledge, which in the future can and will be implemented for developmental biology and regenerative medicine applications. © 2015 Aleksandra Rak-Raszewska et al.

Nishikawa M.,Medical and Research Services | Nishikawa M.,University of California at Los Angeles | Nishikawa M.,Renal Regeneration Laboratory | Yanagawa N.,Medical and Research Services | And 8 more authors.
In Vitro Cellular and Developmental Biology - Animal | Year: 2013

Successful derivations of specific neuronal and glial cells from embryonic stem cells have enormous potential for cell therapies and regenerative medicine. However, the low efficiency, the complexity of induction method, and the need for purification represent obstacles that make their application impractical. In this study, we found that PDGFRα+ cells derived from mouse embryonic stem cells (mESC) can serve as a useful source from which to induce cells that express γ-aminobutyric-acid (GABA)-releasing (GABAergic) neuronal markers. PDGFRα+ cells were induced from mESC on collagen IV-coated plates in mesenchymal stem cell (MSC) culture medium with limited exposure to retinoic acid, sorted by fluorescence-activated cell sorter and maintained in MSC culture medium containing Y-27632, a Rho-associated kinase inhibitor. We found that supplementation of vascular endothelial growth factor, fibroblast growth factor-basic, and sodium azide (NaN3) to MSC culture medium effectively differentiated PDGFRα+ cells into cells that express GABAergic neuronal markers, such as Pax2, Dlx2, GAD67 NCAM, and tubulin-βIII, while markers for oligodendrocyte (Sox2) and astrocyte (Glast) were suppressed. Immunostaining for GABA showed the majority (86 ± 5%) of the induced cells were GABA-positive. We also found that the PDGFRα+ cells retained such differentiation potential even after more than ten passages and cryopreservation. In summary, this study presents a simple and highly efficient method of inducing cells that express GABAergic neuronal markers from mESC. Together with its ease of maintenance in vitro, PDGFRα+ cells derived from mESC may serve as a useful source for such purpose. © 2013 The Society for In Vitro Biology.

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