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Application of a suitable particle engineering technique by pulsed laser ablation in liquid (PLAL) to modify the physicochemical properties of poorly soluble drugs
摘要： Several disintegration procedures are well known in the field of pharmaceutical technology to improve the solubility, dissolution rate and bioavailability. Only a few, organic materials were applied for micro/nanoparticle generation by pulsed laser ablation in liquid (PLAL), however in the last decade, several studies presented successful production from different active agents. PLAL could be a non-conventional approach by the preformulation of the drug, as a simple, clean (no additional chemicals are needed) and a rapid wet grinding method. It can be stated about the novelty of the work that a poorly water-soluble meloxicam was milled first time by pulsed laser ablation in liquid, where the effect of three different wavelengths, fluence values (energy density) and polymer type (PVP, PVA, Poloxamer) on the habit, structure, solubility and in vitro properties of the drug were investigated. Nearly spherical amorphous micro- and nanoparticles could be reached in a size range between 60-700 nm. Fourier-transform infrared spectroscopy (FT-IR) was applied to check the purity, secondary interaction and High performance liquid chromatography (HPLC) method was used for the determination of the presence of the meloxicam content and the final yield. The results suggest that laser ablation a useful approach to modify the physicochemical properties of the active agents, introduced a novel preparation method in drug preformulation with improved solubility (from 0.0203 mg/mL to 0.0797 mg/mL), dissolution rate (~85%) and also to produce a suitable intermediate product for traditional and alternative drug administration (e.g. pulmonary, nasal, transdermal).
关键词： physicochemical characterization,novel wet-milling,meloxicam,in vitro dissolution,nanosuspension,laser fragmentation
更新于2025-09-23 15:21:01
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Manipulation of the Size and Phase Composition of Yttrium Iron Garnet Nanoparticles by Pulsed Laser Post-Processing in Liquid
摘要： Modi?cation of the size and phase composition of magnetic oxide nanomaterials dispersed in liquids by laser synthesis and processing of colloids has high implications for applications in biomedicine, catalysis and for nanoparticle-polymer composites. Controlling these properties for ternary oxides, however, is challenging with typical additives like salts and ligands and can lead to unwanted byproducts and various phases. In our study, we demonstrate how additive-free pulsed laser post-processing (LPP) of colloidal yttrium iron oxide nanoparticles using high repetition rates and power at 355 nm laser wavelength can be used for phase transformation and phase puri?cation of the garnet structure by variation of the laser ?uence as well as the applied energy dose. Furthermore, LPP allows particle size modi?cation between 5 nm (ps laser) and 20 nm (ns laser) and signi?cant increase of the monodispersity. Resulting colloidal nanoparticles are investigated regarding their size, structure and temperature-dependent magnetic properties.
关键词： laser melting,yttrium iron oxide,monodisperse,laser fragmentation,phase transformation,garnet,perovskite,laser ablation,ferrimagnetic nanoparticles
更新于2025-09-23 15:19:57
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Synthesis of silicon nanoparticles by laser ablation at low fluences in water and ethanol
摘要： Colloidal silicon nanoparticles (Si-nc) where synthesized by laser ablation of a solid Si target in water and ethanol. The target was immersed in a vessel containing the solvent and irradiated during 5 and 10 min at different ?uences: 0.530, 0.608, 0.687 J cm?2. Ablation was carried out using a laser wavelength of 1064 nm. The obtained colloidal nanoparticles were irradiated after the synthesis to evaluate if laser fragmentation could be produced. In addition, a series of nanoparticles using ethanol as liquid medium was synthesized ablating with 532 nm. Colloidal nanoparticles were structurally characterized by Raman spectroscopy and Transmission Electron Microscopy. Size of the Si-nc were calculated by the theorical models: Bond Polarizability Model (BPM) and One-Phonon Con?nement Model (PCM), where nanocrystals ranging from 2 to 11 nm were found.
关键词： Si nanoparticles,laser fragmentation,laser ablation in liquids
更新于2025-09-19 17:13:59
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Evaluation of Limiting Sensitivity of the One-Color Laser Fragmentation/Laser-Induced Fluorescence Method in Detection of Nitrobenzene and Nitrotoluene Vapors in the Atmosphere
摘要： The paper presents the results of a numerical evaluation of limiting sensitivity of the method for detecting vapors of nitrocompounds in the atmosphere based on one-color laser fragmentation (LF)/laser-induced ?uorescence (LIF) of NO fragments via A2Σ+ (v’ = 0) ← X2Π (v” = 2) transition. The calculations were performed using the developed kinetic model of the one-color LF/LIF process under consideration. The calculations take into account the in?uence of ambient nitrogen dioxide as a limiter of the sensitivity of the method when operating in a real atmosphere. It is shown that if the nitrogen dioxide concentration in the atmosphere does not exceed a value of 10 ppb, the maximum detectable vapor concentrations of nitrobenzene and o-nitrotoluene are several ppb. It is also shown that the method of single-frequency one-color excitation usually used for the detection of nitrocompounds does not allow achieving the maximum e?ciency of the LF/LIF process.
关键词： nitrobenzene,nitrotoluene,laser fragmentation,detection,laser-induced ?uorescence
更新于2025-09-16 10:30:52
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Laser fragmentation induced defect‐rich cobalt oxide nanoparticles for electrochemical oxygen evolution reaction
摘要： Sub-5 nm cobalt oxide nanoparticles were produced in a water flowing system by pulsed laser fragmentation in liquid (PLFL). Particle fragmentation from 8 nm to 4 nm was observed and proposed to be induced by the oxidation process in water where oxidative species were present and the local temperature was rapidly elevated under laser irradiation. Significantly higher surface area, crystal phase transformation and formation of structural defects (Co2+ defects and oxygen vacancies) through the PLFL process were evidenced by a detailed structural characterization using nitrogen physisorption, electron microscopy, synchrotron X-ray diffraction and X-ray photoelectron spectroscopy. When employed as electrocatalysts for the oxygen evolution reaction under alkaline conditions, the fragmented cobalt oxides exhibited superior catalytic activity over pristine and nanocasted cobalt oxides, with delivering a current density of 10 mA/cm2 at 369 mV and a Tafel slope of 46 mV/dec, which is attributed to: (i) a larger exposed active surface area, (ii) formation of defects and iii) an increased charge transfer rate. The study provides an effective approach to engineer cobalt oxide nanostructure in a water flowing system, which shows great potential for sustainable production of active cobalt catalysts.
关键词： structural defects,cobalt oxide,nanostructure,Oxygen evolution reaction,laser fragmentation
更新于2025-09-11 14:15:04