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Controlled transition of microcapsules from coil conformation to globule during the expansion of the pulse jet of nanoparticle suspension of TiO2 in supercritical (CO2) polyethylene glycol solution
摘要： The process of microencapsulation of titanium dioxide nanoparticles during the expansion of a supersonic jet of TiO2 suspension in a solution of polyethylene glycol (PEG 8000) in supercritical CO2 into a vacuum and background gas (helium) has been studied experimentally. The dependence of the position of the microcapsule transition point on the jet axis from the coil to a globular conformation on the temperature in the reactor and on the pressure of the background gas at different co-solvent concentrations has been established. A “coil?globule” re-entrant transition has been recorded at a greater distance from the nozzle exit than the point of collapse.
关键词： supersonic jet,polyethylene glycol,microencapsulation,supercritical CO2,coil-globule transition,titanium dioxide
更新于2025-09-12 10:27:22
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Spray-Assisted Coil-Globule Transition for Scalable Preparation of Water-Resistant CsPbBr <sub/>3</sub> @PMMA Perovskite Nanospheres with Application in Live Cell Imaging
摘要： Despite their impressive optical properties, lead halide perovskite quantum dots (PQDs) have not realized their potential, especially in bioimaging applications, as they suffer from poor moisture and thermal stability, solvent incompatibility, and significant toxicity. Here, a spray-assisted coil–globule transition method for encapsulating CsPbBr3 (CPB) PQDs into poly(methyl methacrylate) (PMMA) polymer nanospheres is reported. Polyvinylpyrrolidone-capped CPB PQDs are synthesized via the ligand assisted reprecipitation method in dichloromethane. After dissolving PMMA, the above precursor solution is sprayed into petroleum ether under high pressure N2. High-pressure nebulization restricts the interactions between PMMA polymer chains, resulting in the formation of ≈112 nm nanoscale composite spheres after a coil–globule transition. The CPB@PMMA nanospheres not only possess 73% quantum yields but retain 81% of fluorescence intensity after the exposure to water for over 80 days. Due to their confined size and biocompatible encapsulation, they are readily available for cellular uptake and exhibit no toxicity on live HeLa cells. Furthermore, the PMMA surface allows for functional surface modification, carrying the possibility of targeting specific biological species and processes.
关键词： cell imaging,spray,quantum dots,coil–globule transition,perovskite
更新于2025-09-10 09:29:36