Base-Controlled Cu-Catalyzed Tandem Cyclization/Alkynylation for the Synthesis of Indolizines

A base-controlled Cu-catalyzed tandem cyclization/alkynylation of propargylic amines provides rapid access to functionalized indolizine derivatives under mild reaction conditions. The reaction first proceeded via a 5-<i>endo-dig</i> aminocupration, followed by a coupling between the copper-bound intermediate and alkynyl bromide, to afford the products in good to excellent yields. The successful tandem reaction is attributed to the unique property of the bases, DBU (1,8-diaza­bicyclo­[5.4.0]­undec-7-ene) and MTBD (7-methyl-1,5,7-triaza­bicyclo­[4.4.0]­dec-5-ene used)

Regulation of Cell Signaling Factors Using PLGA Nanoparticles Coated/Loaded with Genes and Proteins for Osteogenesis of Human Mesenchymal Stem Cells

Transfection of specific genes and transportation of proteins into cells have been a focus of stem cell differentiation research. However, it is not easy to regulate codelivery of a gene and a protein into cells. For codelivery into undifferentiated cells (human mesenchymal stem cells (hMSCs)), we used biodegradable carriers loaded with Runt-related transcription factor 2 (RUNX2) protein and coated with bone morphogenetic protein 2 (BMP2) plasmid DNA (pDNA) to induce osteogenesis. The released gene and protein were first localized in the cytosol of transfected hMSCs, and the gene then moved into the nucleus. The levels of internalized PLGA nanoparticles were tested using different doses and incubation durations. Then, transfection of BMP2 pDNA was confirmed by determining mRNA and protein levels and acquiring cell images. The same techniques were used to assess osteogenesis of hMSCs both <i>in vitro</i> and <i>in vivo</i> upon internalization of PLGA NPs carrying the BMP2 gene and RUNX2 protein. Detection of specific genes and proteins demonstrated that cells transfected with PLGA NPs carrying both the BMP2 gene and RUNX2 protein were highly differentiated compared with other samples. Histological and immunofluorescence analyses demonstrated that transfection of PLGA nanoparticles carrying both the BMP2 gene and RUNX2 protein dramatically enhanced osteogenesis of hMSCs

Peroxynitrite-Scavenging Glycosides from the Stem Bark of <i>Catalpa ovata</i>

Ten new glycosides, 6,10-<i>O</i>-di-<i>trans</i>-feruloyl catalpol (<b>1</b>), 6,6′-<i>O</i>-di-<i>trans</i>-feruloyl catalpol (<b>2</b>), 3,4-dihydro-6-<i>O</i>-di-<i>trans</i>-feruloyl catalpol (<b>10</b>), (8<i>R</i>,7′<i>S</i>,8′<i>R</i>)-lariciresinol 9′-<i>O</i>-β-d-(6-<i>O</i>-<i>trans</i>-feruloyl)­glucopyranoside (<b>17</b>), and ovatosides A–F (<b>18</b>–<b>22</b>, <b>24</b>), were isolated from the stem bark of <i>Catalpa ovata</i> along with 19 known compounds. All isolates, except <b>6</b> (catalposide) and <b>9</b> (6-<i>O</i>-veratroyl catalpol), were found to scavenge peroxynitrite (ONOO^–) formed by 3-morpholinosydnonimine. In particular, 12 compounds showed potent activity, with IC₅₀ values in the range 0.14–2.2 μM

Construction of PLGA Nanoparticles Coated with Polycistronic <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i> Genes for Chondrogenesis of Human Mesenchymal Stem Cells

Transfection of a cocktail of genes into cells has recently attracted attraction in stem cell differentiation. However, it is not easy to control the transfection rate of each gene. To control and regulate gene delivery into human mesenchymal stem cells (hMSCs), we employed multicistronic genes coupled with a nonviral gene carrier system for stem cell differentiation. Three genes, <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i>, were successfully fabricated in a single plasmid. This multicistronic plasmid was complexed with the polycationic polymer polyethylenimine, and poly­(lactic-<i>co</i>-glycolic) acid (PLGA) nanoparticles were coated with this complex. The uptake of PLGA nanoparticles complexed with the multicistronic plasmid was tested first. Thereafter, transfection of <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i> was evaluated, which increased the potential for chondrogenesis of hMSCs. The expression of specific genes triggered by transfection of <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i> was tested by RT-PCR and real-time qPCR. Furthermore, specific proteins related to chondrocytes were investigated by a glycosaminoglycan/DNA assay, Western blotting, histological analyses, and immunofluorescence staining. These methods demonstrated that chondrogenesis of hMSCs treated with PLGA nanoparticles carrying this multicistronic genes was better than that of hMSCs treated with other carriers. Furthermore, the multicistronic genes complexed with PLGA nanoparticles were more simple than that of each single gene complexation with PLGA nanoparticles. Multicistronic genes showed more chondrogenic differentiation than each single gene transfection methods

Porous PVDF As Effective Sonic Wave Driven Nanogenerators

Piezomaterials are known to display enhanced energy conversion efficiency at nanoscale due to geometrical effect and improved mechanical properties. Although piezoelectric nanowires have been the most widely and dominantly researched structure for this application, there only exist a limited number of piezomaterials that can be easily manufactured into nanowires, thus, developing effective and reliable means of preparing nanostructures from a wide variety of piezomaterials is essential for the advancement of self-powered nanotechnology. In this study, we present nanoporous arrays of polyvinylidene fluoride (PVDF), fabricated by a lithography-free, template-assisted preparation method, as an effective alternative to nanowires for robust piezoelectric nanogenerators. We further demonstrate that our porous PVDF nanogenerators produce the rectified power density of 0.17 mW/cm³ with the piezoelectric potential and the piezoelectric current enhanced to be 5.2 times and 6 times those from bulk PVDF film nanogenerators under the same sonic-input