We demonstrate luminescent carbon nanostructures (LCNs) with yellow-orange emission synthesized from citric acid (CA) and urea by hydrothermal treatment. LCNs were treated in water and N,N- dimethylformamide (DMF) at 160° for 6 hours. In this case, an increase of the solvent polarity provides the shifting of the LCNs luminescence to the longer emissive region. The LCNs mixture treated in DMF was fractionated by size-exclusion chromatography. It was obtained 33 fractions with three types of emissive sites at 460 nm (fractions 1-7 and 11-33), 540 nm (fractions 8-13), and 620 nm (fractions 12-33).
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 the synthesis of a luminescent derivative of biotin molecules with preservation its ability to interact with streptavidin. The luminescent biotin derivative was obtained via hydrothermal treatment of biotin water solution at different temperatures 140-240°C for 2 hours. Modified biotin showed a strong blue emission in the area of 390 nm with an optimal excitation wavelength at 320 nm and the relative quantum yield was 15±2 % for the sample obtained at the highest temperature. It was shown that hydrothermal treatment leads to biotin modifying with a saving of its biological activity.
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.
In this article we report an effective hydrothermal synthesis of bright-emissive nanoparticles from citric acid and ethylenediamine. Also, we demonstrate methods for separation of carbon nanoparticles such as high speed centrifugation and size-exclusion liquid chromatography. These nanoparticles due to their high quantum yield can be used as markers for biological tissues, liquids and cells.
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.
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.
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