In this article, we have demonstrated the promising separation methods for hydrothermally obtained fluorescent molecule formed from citric acid and 1,2 – ethylenediamine. This fluorophore is a derivative of citrazinic acid and is known as a 1,2,3,5-tetrahydro-5-oxo-imidazo[1,2-a]pyridine-7-carboxylic acid (IPCA). Gel electrophoresis and dialysis were applied for the extraction the fluorophore from start materials. IPCA molecule has strong absorption at 350 nm and luminescence at 450 nm with a high quantum yield of around 85±5%. The structure of the fluorophore and polymer-like structures was researched by spectrophotometry, spectrofluorimetry, IR and NMR spectroscopy.
We demonstrate an effective one-pot synthesis of blight-yellow carbon nanoparticles (CNPs) with the photoluminescent (PL) maxima at the area around 600 nm. Hydrothermal synthesis was used as fast and cheap way for one-step CNPs synthesis and modification. Sodium dextran sulfate (DSS) was used as the main precursor for the synthesis; polyethylene glycol based polymer (Jeffamine) and concentrated phosphoric acid were considered as surface passivation agents. The synthesized CNPs have typical for CNPs excitation-dependent PL.
In this paper, we show a low temperature normal pressure synthesis of a blue emissive organic fluorophore. The organic fluorophore molecule - 1, 2, 3, 5-tetrahydro-5-oxo-imidazo [1, 2-a] pyridine-7-carboxylic acid (IPCA) - consists of derivatives of imidazole and benzoic rings with a carboxylic group. The molecule has a strong emission maximum at around 450 nm when excitation of 350 nm us used and is correlated with PL spectra of carbon nanoparticles. The quantum yield was found to be relatively high: around 55%. IPCA luminescent properties are similar to the reported for some carbon nanostructures, obtained via hydrothermal synthesis from citric acid and ethylenediamine.
Polyelectrolyte microcapsules are one of the most successful developments in the direction of target drug delivery. Nevertheless, to encapsulate low molecular weight compounds and to deliver the targeted drugs it is necessary to modify the surface of the microcapsules. Silica nanostructures obtained as result of hydrolysis of (3-Aminopropyl)- triethoxysilane (APTES) were used for the modification of the microcapsules. This material shows no toxic effect on cells and is capable of biodegradation. Amino-groups in the structure of APTES make it possible for further direct bioconjugation.
Photoluminescent (PL) carbon nanoparticles (CNPs) have been synthesized by one-step microwave irradiation from water solution of sodium dextran sulfate (DSS) as the sole carbon source. Microwave (MW) method is very simple and cheap and it provides fast synthesis of CNPs. We have varied synthesis time for obtaining high luminescent CNPs. The synthesized CNPs exhibit excitation-dependent photoluminescent. Final CNPs water solution has a blue- green luminescence. CNPs have low cytotoxicity, good photostability and can be potentially suitable candidates for bioimaging, analysis or analytical tests.
Photoluminescent (PL) properties of carbon-based nanomaterials obtained on the base of sodium dextran sulfate (DS) were compared. DS water solution, dry powder and co-precipitated inside pores of CaCO3 microparticles solution were thermally treated and clear difference between these materials was found. Effect of spatial restriction of CaCO3 pores showed itself in the identity of PL properties for material, obtained by thermal and hydrothermal treatment; in the absence of CaCO3 microparticles the PL spectra were quite different.
Delivery and spatial localization of upconversion luminescent microparticles [Y2O3:Yb, Er] (mean size ∼1.6 μm) and quantum dots (QDs) (CuInS2/ZnS nanoparticles coated with polyethylene glycol-based amphiphilic polymer, mean size ∼20 nm) inside rat skin was studied in vivo using a multimodal optical imaging approach. The particles were embedded into the skin dermis to the depth from 300 to 500 μm through microchannels performed by fractional laser microablation. Low-frequency ultrasound was applied to enhance penetration of the particles into the skin. Visualization of the particles was revealed using a combination of luminescent spectroscopy, optical coherence tomography, confocal microscopy, and histochemical analysis. Optical clearing was used to enhance the image contrast of the luminescent signal from the particles. It was demonstrated that the penetration depth of particles depends on their size, resulting in a different detection time interval (days) of the luminescent signal from microparticles and QDs inside the rat skin in vivo. We show that luminescent signal from the upconversion microparticles and QDs was detected after the particle delivery into the rat skin in vivo during eighth and fourth days, respectively. We hypothesize that the upconversion microparticles have created a long-time depot localized in the laser-created channels, as the QDs spread over the surrounding tissues.
The goal of this study is to quantify the impact of the in vivo photochemical treatment of rats with obesity using indocyanine green (ICG) dissolved in saline or dispersed in an encapsulated form at NIR laser irradiation, which was monitored by tissue sampling and histochemistry. The subcutaneous injection of the ICG solution or ICG encapsulated into polyelectrolyte microcapsules, followed by diode laser irradiation (808 nm, 8 W/cm2, 1 min), resulted in substantial differences in lipolysis of subcutaneous fat. Most of the morphology alterations occurred in response to the laser irradiation if a free-ICG solution had been injected. In such conditions, membrane disruption, stretching, and even delamination in some cases were observed for a number of cells. The encapsulated ICG aroused similar morphology changes but with weakly expressed adipocyte destruction under the laser irradiation. The Cochran Q test rendered the difference between the treatment alternatives statistically significant. By this means, laser treatment using the encapsulated form of ICG seems more promising and could be used for safe layerwise laser treatment of obesity and cellulite.
In this article we report an effective and simple method for synthesis of high luminescent carbon nanodots (CDs). In our work as a carbon source sodium dextran sulfate (DS) was used because it is harmless, its analogs are used in medicine as antithrombotic compounds and blood substitutes after hemorrhage. was used as a substrate We investigated the influence of temperature parameters of hydrothermal synthesis on the photoluminescence (PL) intensity and position of emission maxima. We discovered that the PL intensity can be tuned by changing of synthesis temperature and CD concentration.
The goal of this work is to quantify impact of in vivo photochemical treatment using indocyanine green (ICG) or encapsulated ICG and NIR laser irradiation through skin of rat with obesity by the follow up tissue sampling and histochemistry. After 1 hour elapsed since 1-min light exposure samples of rat skin with subcutaneous tissue of thickness of 1.5-2.5 mm were taken by surgery from rats within marked 4-zones of the skin site. For hematoxylin-eosin histological examination of excised tissue samples, fixation was carried out by 10%-formaldehyde solution. For ICG and encapsulated ICG subcutaneous injection and subsequent 1-min diode laser irradiation with power density of 8 W/cm2, different necrotic regions with lipolysis of subcutaneous fat were observed. The obtained data can be used for safe layer-by-layer laser treatment of obesity and cellulite.
Delivery of upconversion microparticles [Y2O3:Yb, Er] and quantum dots (CuInS2/ZnS coated with PEG-based amphiphilic polymer) into rat skin using the fractional laser microablation has been studied in vivo. Luminescence spectroscopy, optical coherence tomography, confocal microscopy, and histochemical analysis were used for visualization of nanoparticles in microchannels. Results have shown that the upconversion microparticles are detected more efficiently in comparison with the quantum dots. The fluorescence intensity of the inserted upconversion microparticles is higher, when the Omnipaque™ was applied as a skin optical clearing agent. The fluorescent images of upconversion nanoparticle distribution indicate the advantage of particle delivery into skin by ultrasound.
Laser radiation was used for permeability increase up to destroy of polyelectrolyte capsules. Silver and gold nanoparticles was synthesized and incorporated into capsule shells to attain the sensitivity of microcapsules to laser radiation. Lasers of different power and wavelength were used. The sensitivity of nanocomposite shell to laser radiation can be controlled by nanoparticle shape, content and distribution into the shell.
Iron oxide nanoparticles and polymer planar films with different number of layers of iron oxide nanoparticles have been fabricated by the layer-by-layer alternating adsorption technique. It was established that the thickness of the PAH/iron oxide film and its refractive index increases with the increase of the layer number. The microwave irradiation affects the thickness of the PAH/iron oxide film and their refractive index. The increase of refractive index and decrease of thickness of nanocomposite films were observed. The electronic paramagnetic resonance (EPR) spectra of planar films were measured. It was found that parameters of the EPR spectra are sensitive to the number of nanoparticles layers.
Aqueous suspension of iron oxide nanoparticles stabilized by citric acid has been synthesized. Nanoparticles were characterized by transmission electron microscopy. Nanoparticles size distribution was estimated by dynamic laser light scattering method. Absorption spectra of nanoparticles suspensions at different concentrations were recorded in visible part of optical band. Zeta-potential of nanoparticles was measured. Absorption and reflection spectra of aqueous suspension of nanoparticles in 7.8 - 11.2 GHz frequency range have been obtained. A frequency ranges with maximal sensitivity of microwave spectra parameters to nanoparticles concentration were found.
A layer-by-layer nanoassembly (LbL) allows production of ultrathin films with a precision of 1-2 nm and needed composition across the multilayer. It was used in combination with traditional lithography to develop micropatterns in ordered nanoparticle multilayers. A selective nanoparticle film growth was also demonstrated for microchannel silicon chips. Microfluidic properties of nanoorganized polymer microcapsules were studied with the microchannel device. Nanoorganized microcapsules production: A LbL-assembly of 20-nm thick
poly(styrenesulfonate) / poly(allylamine) shell on microtemplates and loading such hollow polyion shells with enzymes allowed fabrication of catalytic "bioreactors," as it was demonstrated for glucose oxidase, hemoglobin, and myoglobin ensembles.
A microfluidic system was designed, fabricated and implemented to study the behavior of polyelectrolyte capsules flowing in microscale channels. The silicon component of the system contains microchannels that leads into constrictions, which were fabricated using lithography techniques. Polyelectrolyte microcapsules were also fabricated with well-known layer-by-layer assembly technique, on a spherical template. Once the template was removed, the resulting hollow capsules were introduced into the system. The behavior of the capsules at the constrictions was visualized and the properties of the capsules were investigated. Capsules recovered from the system appear to have a undergone a plastic deformation.
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