The alternating current (AC) and direct current (DC) electrical response of a number of n-alkyl methacrylate polymers with a charge transporting pendant carbazole ring were studied.
An effective strategy to control the Förster resonance energy transfer (FRET) of a donor/acceptor emitter pair that were attached to a 60 nm poly(propargyl acrylate)(PA) nanoparticle using temperature variations was developed. The size dependent properties of a poly-(ethylene oxide)-poly-(propylene oxide)-poly-(ethylene oxide) (PEO-PPO-PEO) block copolymer (poloxamer) was exploited to vary the spatial separation of the emitters and vary the FRET efficiency. Specifically, a 2% change in FRET efficiency between the donor/acceptor pair was achieved per 1 °C change in temperature from 49 °C to 60 °C when using a poloxamer of 2950 g mol-1 molecular weight, with sections of PPO consisting of 32 repeat units, PEO sections consisting of 12 repeat units and a lower critical solution temperature (LCST) of 58 °C. The methodology presented in this effort is easily extended to other temperature regimes through a judicious choice in poloxamer and corresponding LCST.
<p>The down-conversion of high energy light with a fluorescent material may provide sufficient emission intensity to invoke a measurable neurological response in optogentically-active neurons. This work describes the use of anthracene-containing copolymers for use as a fixed emission material in optogenetic electrophysiology to demonstrate the feasibility of this technique. An anthracene-modified methacrylate was synthesized and copolymerized with methyl methacrylate to produce glassy copolymers with physical properties like those of poly(methyl methacrylate) (PMMA). The fluorescence in both solution and solid states are like those of pure anthracene and overlap fully with the absorption spectrum of channelrhodpsin-2. Scintillation is observed but is weak compared to fluorescence. The copolymers were found to be non-toxic to neuronal cultures. Whole cell patching measured the voltage changes of neurons under UV-irradiation in the absence and presence of a copolymer film. Increased frequencies and amplitudes of electrical events were observed in the presence of the polymers. </p> <div> <hr> </div>
New methacrylate monomers with carbazole moieties as pendant groups were synthesized by multistep syntheses starting from carbazoles with biphenyl substituents in the aromatic ring. The corresponding polymers were prepared using a free‐radical polymerization. The novel polymers contain N‐alkylated carbazoles mono‐ or bi‐substituted with biphenyl groups in the aromatic ring. N‐alkyl chains in polymers vary by length and structure. All new polymers were synthesized to evaluate the structural changes in terms of their effect on the energy profile, thermal, dielectric, and photophysical properties when compared to the parent polymer poly(2‐(9H‐carbazol‐9‐yl)ethyl methacrylate). According to the obtained results, these compounds may be well suited for memory resistor devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 70–76
Vancomycin is a potent antibacterial drug that suffers from poor bioavailability due to its poor water solubility and relatively high molecular weight. Consequently, the application of vancomycin to treat bacteria-induced disease is limited. In this study, the ability of a temperature-stimulated propargyl acrylate−poloxamer nanocomposite (PAPN) system to encapsulate and release vancomycin is investigated. A controllable encapsulation and release system can be used to not only increase and prolong the bioavailability of vancomycin but also activate vancomycin with a temperature change. The PAPN system was prepared using an emulsion polymerization of propargyl acrylate followed by a surface decoration with a poloxamer at a precisely controlled grafting density. The activity of the PAPN system loaded with vancomycin is compared to that of the free drug and unmodified propargyl acrylate nanoparticles. It is shown that the activity of the PAPN system loaded with vancomycin is comparable to that of a freshly prepared, free-floating vancomycin solution. Upon storage, the activity of the free vancomycin in solution decreases, while the PAPN system loaded with vancomycin retains its high activity. Additionally, the PAPN system is able to effectively encapsulate and deactivate vancomycin until heated above a lower critical solution temperature (LCST). At temperatures above the LCST, the PAPN system releases vancomycin restoring the activity of the drug.
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