Hyperbranched polyglycerol (HPG) is modified with dodecanethiol (DS) via the "thiol-ene" click reaction to obtain an amphiphilic product DSHPG. The molecular structures of DSHPG samples are characterized by NMR, FTIR, and GPC, and the thermal behaviors are characterized by DSC and TGA. Gold nanoparticles (Au NPs) are prepared with DSHPG as the stabilizer and surface-modification reagent. The size of Au NPs can be tuned by changing the molecular weight of HPG. It is observed that the HPG molecular weights of 1123, 3826, and 55,075 lead to the NP diameters of 4.1 nm for Au@DSHPG-1, 9.7 nm for Au@DSHPG-2, and 15.1 nm for Au@DSHPG-3, respectively. The morphology and size of Au NPs are characterized by TEM and DLS. Especially, the dispersion abilities of Au NPs in different pure solvents and co-solvent mixtures are investigated. The long alkyl chains on DSHPG give the ability of Au NPs to be well dispersed in nonpolar solvents. Hydrocarbon-based nanofluids can be obtained from the hydrophobic Au NPs dispersed into a series of hydrocarbons. The dispersion stability for Au NPs in hydrocarbons is monitored by UV-Vis spectroscopy, and the relative concentration of Au NPs is observed to still maintain over 80% after 3600 h.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5585120 | PMC |
http://dx.doi.org/10.1186/s11671-017-2296-1 | DOI Listing |
Adv Mater
December 2024
Department of Chemical and Biological Engineering, Korea University, Seoul, 02841, Republic of Korea.
In this study, a novel phenomenon is identified where precise control of topology and generation of polyglycerol induce the retention of Na ions in biological buffer systems, effectively inhibiting ice crystal growth during cryopreservation. Unlike linear and hyperbranched counterparts, densely-packed hydroxyl and ether groups in 4th-generation dendritic polyglycerol interact with the ions, activating the formation of hydrogen bonding at the ice interface. By inhibiting both intra- and extracellular ice growth and recrystallization, this biocompatible dendritic polyglycerol proves highly effective as a cryoprotectant; hence, achieving the cell recovery rates of ≈134-147%, relative to those of 10% dimethyl sulfoxide, which is a conventional cryoprotectant for human tongue squamous carcinoma (HSC-3) cell line and human umbilical vein endothelial (HUVEC) cells.
View Article and Find Full Text PDFInt J Pharm
January 2025
Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC 27710; Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707. Electronic address:
J Phys Chem B
December 2024
Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin 14195, Germany.
The interaction of unfractionated heparin (UFH) with universal heparin reversal agent 7 (UHRA-7) is investigated. UHRA-7 is composed of a hyperbranched polyglycerol core onto which an array of methylated tris(2-aminoethylamine) (Me-TREN) charged groups is grafted, which in turn are shielded with a layer of small chain poly(ethylene glycol) methyl ether (mPEG) chains. This system has previously been shown to be biocompatible and to be effective at neutralizing heparin.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2024
Department of Pharmaceutical Sciences, North Carolina Central University, Durham, NC 27707, USA.
This paper reports the development of a highly crosslinked hyper-branched polyglycerol (HPG) polymer bound to elastin-like proteins (ELPs) to create a membrane that undergoes a distinct closed-to-open permeation transition at 32 °C. The crosslinked HPG forms a robust, mesoporous structure (150-300 nm pores), suitable for selective filtration. The membranes were characterized by FTIR, UV-visible spectroscopy, SEM, and AFM, revealing their structural and morphological properties.
View Article and Find Full Text PDFMacromol Rapid Commun
November 2024
Donostia International Physics Center (DIPC), Paseo Manuel Lardizábal 4, Donostia-San Sebastián, 20018, Spain.
In the present study, low molecular weight cyclic polyglycidol is used as a macroinitiator for hypergrafting glycidol and producing cyclic graft hyperbranched polyglycerol (cPG-g-hbPG) in the molecular weight range of 10-10 g mol. Linear graft hyperbranched polyglycerol (linPG-g-hbPG) and hyperbranched polyglycerol (hbPG) are prepared as reference samples. This creates a family of hbPG structures with cyclic, linear, and star cores, allowing to evaluate their properties in solution and in bulk.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!