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In vivo photoacoustic time-of-flight velocity measurement of single cells and nanoparticles 总被引:1,自引:0,他引:1
Sarimollaoglu M Nedosekin DA Simanovsky Y Galanzha EI Zharov VP 《Optics letters》2011,36(20):4086-4088
Optical techniques for in vivo measurement of blood flow velocity are not quite applicable for determination of velocity of individual cells or nanoparticles. Here, we describe a photoacoustic time-of-flight method to measure the velocity of individual absorbing objects by using single and multiple laser beams. Its capability was demonstrated in vitro on blood vessel phantom and in vivo on an animal (mouse) model for estimating velocity of gold nanorods, melanin nanoparticles, erythrocytes, leukocytes, and circulating tumor cells in the broad range of flow velocity from 0.1?mm/s to 14?cm/s. Object velocity can be used to identify single cells circulating at different velocities or cell aggregates and to determine a cell's location in a vessel cross-section. 相似文献
2.
Alimpiev S Grechnikov A Sunner J Karavanskii V Simanovsky Y Nikiforov S 《Rapid communications in mass spectrometry : RCM》2011,25(1):140-146
A rotating ball interface for surface‐assisted laser desorption/ionization (SALDI) mass spectrometry was designed and tested. One side of the ball was exposed to atmospheric pressure and the other to the vacuum in a time‐of‐flight mass spectrometer. Analytes (arginine, atenolol, reserpine, tofisopam, and chloropyramine) were applied using electrospray to a silicon substrate on the atmospheric side, the ball was rotated 180°, and the analyte was desorbed on the vacuum side using a pulsed, 200 Hz, 355 nm laser. In order to increase the desorption area, the laser focus was scanned over the substrate in a raster pattern repeated once every second. The design allows for rapid sample throughout with a sample turn‐around time as short as 5 s. Newly produced porous silicon substrates initially yielded very low ion signals, and they required several hundred laser shots to attain maximum sensitivity. In contrast, amorphous silicon did not require such ‘activation’. Quantitative analysis showed a sample‐to‐sample reproducibility of about 10%. The sensitivities with model analytes were in the 1000 to 10 000 ions/fmole range and detection limits in the low fg range. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
Kravets K. Yu. Grechnikov A. A. Simanovsky Ya. O. 《Journal of Analytical Chemistry》2021,76(14):1588-1595
Journal of Analytical Chemistry - The results of a study of the pathways of ion formation from organic compounds in Atmospheric Pressure Laser Plasma Ionization (APLPI) are presented. The... 相似文献
4.
Acoustical Physics - The article reviews the achievements and problems of opto(photo)acoustics in recent years for biomedical applications in real media and real optoacoustic (OA) conversion modes.... 相似文献
5.
The present paper continues the presentation of the results of studies started in [1]. The referred paper reports the development of the optical method for component analysis of natural gas mixtures with different compositions, allowing conducting measurements in real time. The method is based on the measurement of the absorption coefficients for the analyzed gas mixture at several wavelengths within the infrared region of the spectrum (7?C14 ??m), with the selected number and values of wavelengths depending on the category of the gas mixture. The resulting accuracy of the determination of the main components of gas mixtures including methane, ethane, propane, butane, pentane and carbon dioxide is sufficient for the use of the developed method for the monitoring of the component composition of natural gas in pipelines. 相似文献
6.
A. A. Grechnikov A. S. Borodkov S. S. Alimpiev S. M. Nikiforov Ya. O. Simanovsky 《Journal of Analytical Chemistry》2013,68(1):19-26
The efficiency of laser desorption/ionization of twenty compounds from the surface of amorphous silicon is studied as a function of proton affinity (PA) and gas-phase basicity (GB). The values of GB and PA are obtained from quantum-chemical calculations using the density functional theory in the B3LYP model with the 6–311++G(3df,3pd) basis set. The values of GB lie in the range from 845 to 977 kJ/mol. The efficiency of laser desorption/ionization exponentially depends on the GB and PA values and for the studied compounds varies from 7 × 10?6 to 1.4 × 10?2. 相似文献
7.
The study is aimed at an increase in the accuracy of the optical method for the detection of the iodine-containing substances
in technological liquids resulting form the processing of the waste nuclear fuel. It is demonstrated that the accuracy can
be increased owing to the measurements at various combinations of wavelengths depending on the concentrations of impurities
that are contained in the sample under study and absorb in the spectral range used for the detection of the iodine-containing
substances. 相似文献
8.
Murgin A. L. Ovsetsina T. I. Andreev P. V. Simanovsky D. V. Egorova A. E. Ivanov V. A. 《Crystallography Reports》2020,65(1):40-42
Crystallography Reports - A new germanate phase, grown in the Li2O · MoO3–CaO–GeO2 pseudoternary system with addition of Cr2O3, has been studied by X-ray diffraction. The... 相似文献
9.
Alimpiev S Grechnikov A Sunner J Karavanskii V Simanovsky Y Zhabin S Nikiforov S 《The Journal of chemical physics》2008,128(1):014711
The generation of ions from silicon substrates in surface-assisted laser desorption ionization (SALDI) has been studied using silicon substrates prepared and etched by a variety of different methods. The different substrates were compared with respect to their ability to generate peptide mass spectra using standard liquid sample deposition. The desorption/ionization processes were studied using gas-phase analyte deposition. Mass spectra were obtained from compounds with gas-phase basicities above 850 kJmol and with molecular weights up to 370 Da. UV, VIS, and IR lasers were used for desorption. Ionization efficiencies were measured as a function of laser fluence and accumulated laser irradiance dose. Solvent vapors were added to the ion source and shown to result in fundamental laser-induced chemical and physical changes to the substrate surfaces. It is demonstrated that both the chemical properties of the substrate surface and the presence of a highly disordered structure with a high concentration of "dangling bonds" or deep gap states are required for efficient ion generation. In particular, amorphous silicon is shown to be an excellent SALDI substrate with ionization efficiencies as high as 1%, while hydrogen-passivated amorphous silicon is SALDI inactive. Based on the results, a novel model for SALDI ion generation is proposed with the following reaction steps: (1) the adsorption of neutral analyte molecules on the SALDI surface with formation of a hydrogen bond to surface Si-OH groups, (2) the electronic excitation of the substrate to form free electron/hole pairs (their relaxation results in trapped positive charges in near-surface deep gap states, causing an increase in the acidity of the Si-OH groups and proton transfer to the analyte molecules), and (3) the thermally activated dissociation of the analyte ions from the surface via a "loose" transition state. 相似文献
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