Other Upconverting Nanoparticles
Up-conversion nanoparticles are a new generation of fluorescents that rely on physical and chemical principles to convert photons from a low-energy state to a high-energy state. These particles typically absorb energy in the infrared (IR) range and emit energy in the visible or ultraviolet (UV) range.
Alfa Chemistry provides other upconverting nanoparticles, including the following:
The Upconverting Luminescent Nanoparticles have wavelengths of 365 nm-800 nm and can be converted with organic solvents or water.
Other Upconverting nanoparticles are green light, UV light, near infrared light, yellow-green and violet blue light.
The products have been widely used in biomedicine, including in vivo bioimaging, in vivo bioimaging, biodetection, immunohistochemistry, microarray detection, and photodynamic therapy to activate photosensitive drugs.
Magnetic Resonance Imaging
The synthesis and characterization of gadolinium-rich upconversion nanoparticles for dual-mode magnetic resonance and optical luminescence imaging is reported by Kostiv et al. NaYF4:Gd3+,Yb3+,Tm3+ core upconversion nanoparticles were obtained by thermal co-precipitation of lanthanide oleate precursors in the presence of oleic acid as a stabilizer. To improve the upconversion emission and increase the number of Gd3+ ions on the nanoparticle surface, a 2.5 nm NaGdF4 shell was grown by a layer-by-layer epitaxy strategy, resulting in a 26 nm core-shell nanoparticle. Both core and core-shell nanoparticles were coated with polyethylene glycol (PEG)-neradione (PEG-Ner) in order to have stable and well-dispersed upconversion nanoparticles in biological media. Fourier transform spectroscopy and thermogravimetric analysis showed the presence of 20 wt% PEG-Ner on the nanoparticle surface. The addition of inert NaGdF4 shell enhanced the emission at 980 nm excitation by a factor of 26 and also affected the T1 and T2 relaxation times. Both r1 and r2 relaxation rates of the PEG-Ner modified nanoparticles were much higher compared to the non-PEGylated particles, thus showing their potential as diagnostic tools for MRI. Together with the enhanced luminescence efficiency, upconverted nanoparticles may represent an effective probe for in vitro and in vivo dual-mode imaging of cells in regenerative medicine, drug delivery and/or photodynamic therapy.
Fig.1 TEM micrographs of (a) OA-capped C-UCNPs, (b) washed C-UCNPs, (c) C-UCNP@PEG-Ner, (d) OA-capped CS-UCNPs, (e) washed CS-UCNPs, and (f) CS-UCNP@PEG-Ner nanoparticles. (Kostiv et al., 2021)
Kurt et al. developed a dual excitation sensing method that uses aptamer-functionalized quantum dots and upconversion nanoparticles exhibiting Stokes and anti-Stokes type excitation profiles, respectively. Combining the inducer-functionalized luminescent nanoparticles with magnetic beads, including short DNA sequences that are partially complementary to the inducer sequence, allows the analyte-free conjugates to be easily separated for fluorescence measurements. UV-Vis spectroscopy, circular dichroism, dynamic light scattering and polyacrylamide gel electrophoresis techniques were used to characterize the developed conjugate probes. Target-specific luminescent conjugates were applied for multiplex detection of model food pathogens, Salmonella typhimurium, and Staphylococcus aureus.
Fig. 2 Illustration of the dual-excitation luminescence strategy for multiplexed detection. (Kurt et al., 2016)
Alfa Chemistry can provide a variety of complex and customized fluorescent quantum dot products. Our products involve perovskites precursors, perovskites quantum dots, quantum dot kit, single layer quantum dots, upconverting nanoparticles and other fluorescent quantum dots. Alfa Chemistry provides products with high fluorescence quantum yield, stable quality and relatively low price. Our products are constantly updated. If the product you need is not in our catalog, please feel free to contact us, we provide relevant custom services.
- Kostiv, Uliana, et al. PEG-Neridronate-Modified NaYF4: Gd3+, Yb3+, Tm3+/NaGdF4 Core-Shell Upconverting Nanoparticles for Bimodal Magnetic Resonance/Optical Luminescence Imaging[J]. ACS omega, 2021, 6(22): 14420-14429.
- Kurt, H. , et al. Dual-excitation upconverting nanoparticle and quantum dot aptasensor for multiplexed food pathogen detection[J]. Biosensors & Bioelectronics, 2016:280-286.
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