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81.
Joseph R. Lakowicz Peter A. Koen Henryk Szmacinski Ignacy Gryczynski Józef Kuśba 《Journal of fluorescence》1994,4(1):117-136
Time-resolved fluorescence spectroscopy is presently regarded as a research tool in biochemistry, biophysics, and chemical physics. Advances in laser technology, the development of long-wavelength probes, and the use of lifetime-based methods, are resulting in the rapid migration of timeresolved fluorescence to the clinical chemistry lab, the patient's bedside, and even to the doctor's office and home health care. Additionally, time-resolved imaging is now a reality in fluorescence microscopy and will provide chemical imaging of a variety of intracellular analytes and/or cellular phenomena. Future horizons of state-of-the-art spectroscopy are also described. Two photon-induced fluorescence provides an increased information content to time-resolved data. Two photoninduced fluorescence, combined with fluorescence microscopy and time-resolved imaging, promises to provide detailed three-dimensional chemical imaging of cells. Additionally, it has recently been demonstrated that the pulses from modern picosecond lasers can be used to quench and/or modify the excited-state population by stimulated emission since the stimulated photons are directed along the quenching beam and are not observed. The phenomenon of light quenching should allow a new class of multipulse time-resolved fluorescence experiments, in which the excited-state population is modified by additional pulses to provide highly oriented systems. 相似文献
82.
Joseph R. Lakowicz Józef Kuśba Yibing Shen Joanna Malicka Sabato D'Auria Zygmunt Gryczynski Ignacy Gryczynski 《Journal of fluorescence》2003,13(1):69-77
We examined the effects of metallic silver island films on resonance energy transfer (RET) between a donor and acceptor bound to double helical DNA. The donor was 4',6-diamidino-2-phenylindole (DAPI) and the acceptor was propidium iodide (PI). Proximity of the labeled DNA to the silver particles resulted in a dramatic increase in RET as seen from the emission spectra and the donor decay times. Proximity to silver particles results in an increase of the Förster distance from 35 Å an to an apparent value of 166 Å. These results suggest a new type of DNA hybridization assays based on RET over distances much longer than the free-space Forster distance. 相似文献
83.
E.M. Goldys A. Barnett F. Xie K. Drozdowicz-Tomsia I. Gryczynski E.G. Matveeva Z. Gryczynski T. Shtoyko 《Applied Physics A: Materials Science & Processing》2007,89(2):265-271
Amplification of fluorescence is a nanoscale phenomenon which is particularly pronounced in close proximity to metal nanostructures.
Due to its sharp distance dependence, it is ideally suited to monitor biorecognition reactions. Using this effect we have
been able to demonstrate ultrasensitive bioassays. Two types of metal nanostructures have been employed, nanometric silver
islands deposited over an ultrathin metal mirror and silver fractal structures. For the first type, metal mirrors (aluminum,
gold, or silver protected with a thin silica layer) were coated with SIFs and an immunoassay (model assay for rabbit IgG or
myoglobin immunoassay) was performed on this surface using fluorescently labeled antibodies. Our results show that SIFs alone
(on a glass surface not coated with metal) enhance the immunoassay signal approximately 3 to 10-fold. Using a metal mirror
instead of glass as support for SIFs leads to up to 50-fold signal enhancement. The second type of metal nanostructures, silver
fractals, were produced by electrochemical reduction of silver nitrate deposited on sapphire covered with a thin conductive
film of indium tin oxide. These structures were used as a substrate for a model rabbit IgG bioassay. The fluorescence resulting
from the binding of antibody labeled with Rhodamine was highly nonuniform with distinctive hot spots. These highly fluorescent
regions were correlated with areas of higher Ag thickness and coverage. Such high values of fluorescence amplification in
both types of nanostructures have been interpreted by using time-resolved fluorescence data and by considering the radiative
properties of plasmons in the environments which promote plasmon coupling.
PACS 87.64.Ni; 81.07.-b; 87.14.-g 相似文献
84.
Ignacy Z. Siemion 《Magnetic resonance in chemistry : MRC》1976,8(8):432-435
The amounts of boat (A) and planar (B) forms for the equilibrium state in D2O and CD3OD/d6-DMSO (1:1) were calculated for seven proline-containing cyclic dipeptides from their 13C n.m.r. spectra. For c-Pro-Val the thermodynamic functions for the conversion between the boat and planar forms have been obtained from measurements of equilibrium constants at different temperatures. 相似文献
85.
86.
Advances in Surface-Enhanced Fluorescence 总被引:4,自引:0,他引:4
Lakowicz JR Geddes CD Gryczynski I Malicka J Gryczynski Z Aslan K Lukomska J Matveeva E Zhang J Badugu R Huang J 《Journal of fluorescence》2004,14(4):425-441
We report recent achievements in metal-enhanced fluorescence from our laboratory. Several fluorophore systems have been studied on metal particle-coated surfaces and in colloid suspensions. In particular, we describe a distance dependent enhancement on silver island films (SIFs), release of self-quenching of fluorescence near silver particles, and the applications of fluorescence enhancement near metalized surfaces to bioassays. We discuss a number of methods for various shaped silver particle deposition on surfaces. 相似文献
87.
Geddes CD Gryczynski I Malicka J Gryczynski Z Lakowicz JR 《Combinatorial chemistry & high throughput screening》2003,6(2):109-117
Metallic surfaces and particles can have dramatic effects on fluorescence, including localized excitation, increased quantum yields, increased photostability and increased distances for resonance energy transfer (RET), and directional emission. While all these effects have not yet been realized in a single system, metal-enhanced fluorescence promises to provide the next generation of high sensitivity fluorescence assays for low copy number detection of biochemical species. 相似文献
88.
Werner Barnard Sylvia O. Paul Petrus H. van Rooyen Ignacy Cukrowski 《Journal of Raman spectroscopy : JRS》2009,40(12):1935-1941
1‐Hydroxyethylidene‐1,1‐diphosphonic acid (HEDP) solutions in the pH range 0.98–13.00 were analysed using FT‐Raman spectroscopy and 31P and 23Na NMR spectroscopy. Vibrational bands for different protonated species were observed in the Raman spectra, whereas only a single NMR signal that shifted with pH was observed for all samples over the entire pH range. No significant shift in the 23Na NMR signal was observed, confirming that formation of Na+(aq) complexes did not take place; hence, no interference with the different protonated forms of HEDP occurred. Vibrational bands were assigned using density functional theory(DFT)‐calculated spectra of the most likely conformers in solution. Multivariate curve resolution was performed on the Raman spectra in the region containing the PO stretching vibrations to determine the number of protonated species formed over the entire pH range. Chemometric analysis compares very favourably with the experimental species distribution diagram which was generated using the reported log KH values. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
89.
Evgenia G. Matveeva Zygmunt Gryczynski Donald R. Stewart Ignacy Gryczynski 《Journal of luminescence》2009,129(11):1281-1285
A ratiometric method for detecting DNA oligomers in bulk solution based on Förster resonance energy transfer (FRET) is described. The two fluorescence signals (green and red), originating from Cy3 (donor, green) and Cy5 (acceptor, red) labels, are simultaneously detected from the pre-hybridized Cy3oligomerY:Cy5oligomerX system. The ratio of red to green intensities is sensitive to the presence of the single-stranded complimentary oligomer, which replaces single-stranded Cy3oligomerY in the donor:acceptor complex and perturbs the FRET. The detection scheme is generally applicable to the detection of DNA and RNA, and particularly micro-RNA. The proposed method is applicable to various double-stranded various lengths targets (manipulation of the sample preparation conditions, such as temperature, incubation time, denaturizing agent, may be needed). 相似文献
90.
Evgenia G. Matveeva Zygmunt Gryczynski Ignacy Gryczynski 《Journal of luminescence》2010,130(4):698-245
A new FRET-based method for the ratiometric detection of DNA oligomers on a surface using TIRF detection mode is reported. The dual-labeled system consisting of two hybridized oligomers, Cy3oligoY:Cy5oligoX was immobilized on the surface, and the total internal reflection fluorescence (TIRF) was used to detect emission signals from the surface. Two signals, green and red, which originated from the green donor Cy3 and the red acceptor Cy5, have been simultaneously detected. When the target single-stranded complimentary oligomer was present in the solution, this oligomer replaced the Cy3oligoY in the donor:acceptor complex on the surface and the ratio of red-to-green signal was dramatically changed. This detection scheme is generally applicable to the detection of DNA or RNA on a surface. 相似文献