Papers by Keyword: Electrospray

Abstract: Nanoparticles have emerged as promising tools for cancer treatment due to their ability to selectively deliver drugs to the tumor site while avoiding significant systemic side effects. Chitosan nanoparticles, among various types of nanoparticles, have gained significant attention due to their biocompatibility, biodegradability, and local drug delivery capacity. The electrospray technique is an efficient method for preparing chitosan nanoparticles, offering reproducibility, scalability, and high drug encapsulation efficiency. This technique has gained popularity due to its ease of use and flexibility in meeting various demands of nanoparticle production. Recent studies have investigated the potential of chitosan nanoparticles prepared by electrospray technique to encapsulate a range of drugs. The method leverages active surface absorption, binding, or complexation with drugs. For example, chitosan-based nanoparticles loaded with DOX and QUE achieved high encapsulation efficiency of 83% and effectively inhibited the growth of HCT-116 cancer cells. Similarly, SNP-CH-DOX-CM nanoparticles showed significant anti-cancer activity against HepG2 tumors. However, it should be noted that the toxicity of nanoparticles is directly related to the concentration of the active substance. Therefore, careful optimization of drug dosing is necessary to minimize any potential toxicity.

Abstract: Electrospray technique has received increasing attentions for intracellular gene delivery as well as production of nanoparticles. In this study, chitosan/pDNA nanoparticles with N/P ratio of 5 were prepared and transferred to HEK293T cells by electrospray technique. Physicochemical characterization of prepared nanoparticles, including size, zeta potential and entrapment efficiency was performed and attachment of pDNA to chitosan was confirmed by gel agarose electrophoresis. Moreover, transfection efficiency was investigated using flow cytometry. MTT assay was performed for cell viability studies. Nanoparticles were prepared at three pDNA concentrations of 10, 55 and 100 μg/ml in fixed N/P ratio. Size of nanoparticles was obtained as 110, 188 and 240 nm, using DLS. SEM showed size of 102.34 ± 10.66 nm for samples having 55 μg/ml pDNA. Zeta potential and entrapment efficiency were +25 mv and 85±4%m respectively. The effect of pDNA concentration, electrospray time and incubation time on transfection efficiency was investigated using Box-Behnken design. Percent of GFP-positive cells was 41.05 ± 3.04% which was taken as an indicator of transfection efficiency. Transfection efficiency of this method was then compared with that of calcium phosphate (31.1 ± 2.4%), showing improved efficiency. Considering the fact that electrospray is an easy, low cost, one-step process which makes low damage to cells and produces monodispersed nanoparticles, the method is introduced as a fascinating approach in gene transfection.

Abstract: The electrospun nanofiber/graphene composites is a promising candidate in the field of flexible strain sensors due to the synergic effect of graphene and the nanofibers. It is an effective way to synthesize a uniform graphene-embedded film by simultaneously electrospinning nanofibers and electrospraying graphene nanosheets. In this paper, we prepare two specimens of different materials to study the interaction between graphene nanosheets and nanofibers under the same process parameters, such as thermoplastic urethane (TPU), polyacrylonitrile (PAN). Then, morphology and mechanical properties are used to characterize the interaction. The mechanical test was conducted by the tensile tester, and the surface morphology of electrospun nanofibrous films was observed through a microscope. By comparing these results, the properties of the graphene nanosheets embedded to different nanofibers are explored. This study provides a good way to select an appropriate nanofiber matrix for the application in flexible strain sensors.

Abstract: The electrospinning/spray technique is a promising approach to fabricate composite films for many applications in flexible electronic devices. In this study, an elastic film with remarkable conductivity is synthesized by electrospinning TPU (thermoplastic polyurethanes) fibers and electrospraying graphene nanosheets into the single collector. This technique allows the graphene nanosheets to adhere uniformly to a carbon textile matrix for promoting its conductivity. But the graphene is possible to be oxidized into graphene oxide during electrospray, which is attributed to the high-voltage field, the rapid evaporation of the solvent and the full exposure to air. And the spinning fibers have the potential to induce the behavior as well. The instability of graphene during the process can make an impact on the overall conductivity and uniformity of composite films. So, we set up a series of experiments on the study of oxidization behavior of graphene and its influence on the performance of composite films. With different parameters, some samples are synthesized to conduct Raman spectroscopy analysis as well as take the measurements of overall conductivity through a 4-point probe electrical conductivity device. The oxidization behavior of graphene during the electrospinning/spray process can be well characterized by the results from the Raman spectrums. And the results of electrical conductivity measurements can provide powerful evidence to ensure the great conductivity of composite films via electrospinning/spray process.

Abstract: A mesoporous TiO₂ photo-electrode for dye-sensitized solar cells (DSSCs) was fabricated by an electrospray method using a solution of dispersed TiO₂ nanocrystals (P25). A mesoporous TiO₂ disk has a larger surface area than P25. The sub micrometer-sized TiO₂ disk promotes light scattering, thereby increasing the photocurrent conversion efficiency. However, the electrosprayed TiO₂ electrodes have many pores and disconnected electron pathways. Thus, we investigated the enhanced electrical contact of an electrosprayed TiO₂ electrode using a hot-pressing process and a titanium tetrachloride (TiCl₄) treatment process. After optimizing the post-treatment process of an electrosprayed TiO₂ electrode, the cell shows conversion efficiency up to 6% at standard sunlight of AM 1.5.

Abstract: An electrospraying process was developed for fabricating a new type of microparticulate third generation solid dispersions (SDs) composed of multiple components with ferulic acid (FA) as a model active pharmaceutical ingredient. The spraying fluids were the co-dissolving solutions of FA, polyvinylpyrrolidone K25 (PVP K25) and sodium dodecyl sulfate (SDS) in 95% ethanol aqueous solutions. Field emission scanning electron microscopic observations showed that the microparticles had an average size of 1.47 ± 0.75 μm. Results from the differential scanning calorimetry analyses suggested that FA and SDS were distributed in the polymer matrix in an amorphous status owing to the compatibility among components resulted from the second-order interactions, as verified by attenuated total reflectance Fourier transform infrared spectra. In vitro dissolution tests demonstrated that the microparticulate SDs could release all the contained FA within 1 minute, extremely faster than the raw FA particles. It can be concluded that electrospraying is a useful tool for creating new generation SDs composed of multiple components for enhancing the rapid dissolution of poorly soluble drugs.

Abstract: We present a process for rapid post-discharge deposition of liquid monomer to form functional coatings at atmospheric pressure. The post-discharge polymerization of dense polyacid and polyether coatings is first depicted versus the energy density deposited by the preliminary surface treatment of polyethylene and polystyrene substrates in air Dielectric Barrier Discharge (DBD) with respect to SEM, to XPS and FTIR-ATR analysis and to polymerization yield determined by mass measurements. The paper focuses on the effect of the filamentary air DBD on surface of the polymer substrates and on post-discharge polymerization mechanism. Indeed, the grafting yield is shown to depend on the energy density deposited by DBD and on the time exposure to air between DBD and monomer deposition, controlling respectively the surface density of radicals and labile peroxides, both triggering the polymerization of vinyl precursors. Then, the effect of deposition conditions on the polymerization yield and related thickness of the functional polymer coatings is shown and special attention is paid to the stability of the coating upon washing.

Abstract: Conventional cleaning technologies have been effective in removal of particles, metals, and organic films. However, two trends motivating the development of new techniques are 1) the desire to minimize the environmental impact of large volumes of cleaning solutions; and 2) the need to clean at the sub-45 nm level, consistent with decreasing feature sizes. We report here on the initial characterization of a system to apply electrospray techniques to variants of the SC-1 and SC-2 solutions, as well as to solvent mixtures. We describe the generation of submicron sized droplets (<1 m radius) of cleaning mixtures and demonstrate a preliminary methodology, using a combination of experimental data and phenomenological modeling approaches, to characterize the physics of the droplet-surface interaction

Abstract: The paper presents experimental results of electrospray deposition of nanopowder onto microfibers. The process is designed to form fibrous filters with an enhanced collection efficiency in the submicron range by covering the fabric with a catalytic material. Polyamide fibres were coated with Al2O3, ZnO, MgO, or TiO2 nanoparticles. The structures obtained were porous at the nanometer scale which increased the total surface area of the catalyst.

Abstract: We present a novel method of using Particle Image Velocimetry in electrospraying process studies. Electrospraying of metal oxides nanoparticles and covering nonwoven nanofiber mat creates composite material for potentially wide applications. Precise control of the electrospinning process gives possibility for better control of nanoparticles deposition and thereby enhancing its relative properties.