Národní úložiště šedé literatury Nalezeno 6 záznamů.  Hledání trvalo 0.01 vteřin. 
Photon-upconversion scanner for multiplexed imaging
Hlaváček, Antonín ; Křivánková, Jana ; Foret, František
In analytical chemistry, multiplexed assays facilitate parallel detection of analytes. The multiplexing reduces the consumption of sample, reagents, and other resources and can be applied for medical diagnostics, the studies of biomolecule interactions, single-cell and singlemolecule assays, environmental monitoring, pathogen detection, multiparameter chemical and biological assays and screening of chemical libraries.
Fast and highly sensitive laser scanner for recording photon-upconversion luminiscence from planar surfaces
Hlaváček, Antonín ; Křivánková, Jana ; Foret, František
Photon-upconversion nanoparticles (UCNPs) are lanthanide-doped nanocrystals that can be excited by nearinfrared light and emit photon-upconversion luminescence of shorter wavelengths. Advantages of UCNPs include near-infrared excitation, multiple and narrow emission bands, negligible autofluorescence and high stability, which make UCNPs ideal luminescence label for use in biological and chemical assays. These assays - e.g. upconversion-linked immunosorbent assay, western blot, lateral flow assay, gel electrophoresis, thin layer chromatography - commonly require the scanning of a planar surface with a high spatial resolution and an excellent sensitivity. The availability of commercial equipment is recently limited because of the novelty of the photon-upconversion phenomenon. Therefore, we report on the construction of photon-upconversion laser scanner. The scanner consists of a laser scanning head, which is attached to a xy-moving stage. The scanning head itself is constructed as an epiluminescence detector with excitation wavelength of 976 nm. A CCD array spectroscope is connected to the laser head and serves as a sensitive detector of photon-upconversion luminescence. The scanner possesses a spatial resolution of 200 μm, the scanning rate is up to 57 points per second and the sensitivity reaches down to single photon-upconversion nanoparticle.
LIBS assessment of spatial photon-upconversion nanoparticle distribution in model plants (R. sativus and L. minor)
Modlitbová, P. ; Novotný, K. ; Hlaváček, Antonín ; Pořízka, P. ; Kaiser, J.
In the present study, radish (Raphanus sativus L.) and common duckweed (Lemna minor L.) were treated with an aqueous dispersion of carboxylated silica-coated photon-upconversion nanoparticles containing rare-earth elements (Y, Yb, and Er). The total content of rare earths and their bioaccumulation factors were determined in the root, hypocotyl, and leaves of R. sativus after 72 hours, and in L. minor fronds after 168 hours. In R. sativus, translocation factors were determined as the ratio of rare earths content in hypocotyl versus roots and in leaves versus hypocotyl. The lengths of the root and hypocotyl in R. sativus, as well as the frond area in L. minor were monitored as toxicity end points. To distinguish rare-earth bioaccumulation patterns, two-dimensional maps of elemental distribution in the whole R. sativus plant and in L. minor fronds were obtained by using laser-induced breakdown spectroscopy with a lateral resolution of 100 μm. Obtained results revealed that the tested nanoparticles became adsorbed on L. minor fronds and R. sativus roots, and got transferred from roots through the hypocotyl into leaves in R. sativus. Our results show that bioaccumulation patterns and spatial distribution of rare earths in nanoparticle-treated plants differ from those of positive control (the mixture of YCl3, YbCl3, and ErCl3).
Arduino-based pressure-driven flow controller for droplet microfluidics
Přikryl, Jan ; Křivánková, Jana ; Hlaváček, Antonín
Droplet-based microfluidic systems bear significant value in an extremely wide range of applications due to its remarkable advantages, nevertheless, their technical demands on precise flow control are high. Here, we present lab-built Arduino-based flow controller fulfilling needs of droplet microfluidics to easily and effectively automate the system. As an additional required accessory, CNC-milled component for vials pressurizing was presented.
Droplet-based microfluidic chip with passive mixer for analysis with photon-upconversion nanoparticles
Křivánková, Jana ; Přikryl, Jan ; Hlaváček, Antonín
Mixing of the fluids in microfluidic chips is important especially in applications, where droplet contents need to be rapidly homogenized. Here, a passive method for mixing in polydimethylsiloxane (PDMS) microchannels is presented. Droplet homogenization was firstly tested with organic stains and subsequently applied for mixing water dispersions of photon-upconversion nanoparticles (UCNPs).\n
Measuring photon-upconversion luminiscence from droplets in microfluidic chips
Hlaváček, Antonín ; Křivánková, Jana ; Přikryl, Jan
UCNPs are lanthanide-doped nanocrystals that can be excited by near-infrared light and emit light of shorter wavelengths. Advantages of UCNPs include multiple and narrow emission bands, negligible autofluorescence and high photostability, which make UCNPs ideal luminescence label for use in droplet microfluidic. Here, we introduce the instrumentation for reading photon-upconversion luminescence of nanoparticles, which are dispersed in water droplets in a microfluidic chip.

Chcete být upozorněni, pokud se objeví nové záznamy odpovídající tomuto dotazu?
Přihlásit se k odběru RSS.