1
|
Chen X, Essner JB, Baker GA. Exploring luminescence-based temperature sensing using protein-passivated gold nanoclusters. NANOSCALE 2014; 6:9594-9598. [PMID: 25017194 DOI: 10.1039/c4nr02069c] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We explore the analytical performance and limitations of optically monitoring aqueous-phase temperature using protein-protected gold nanoclusters (AuNCs). Although not reported elsewhere, we find that these bio-passivated AuNCs show pronounced hysteresis upon thermal cycling. This unwanted behaviour can be eliminated by several strategies, including sol-gel coating and thermal denaturation of the biomolecular template, introducing protein-templated AuNC probes as viable nanothermometers.
Collapse
Affiliation(s)
- Xi Chen
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.
| | | | | |
Collapse
|
2
|
Luchowski R. Two-photon excitation of 2,5-diphenyloxazole using a low power green solid state laser. Chem Phys Lett 2011; 501:572-574. [PMID: 21399731 PMCID: PMC3049896 DOI: 10.1016/j.cplett.2010.11.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This Letter concerns two-photon excitation of 2,5-Diphenyloxazole (PPO) upon illumination from a pulsed 532 nm solid state laser, with an average power of 30 mW, and a repetition rate of 20 MHz. A very agreeable emission spectrum position and shape has been achieved for PPO receiving one- and two-photon excitation, which suggests that the same excited state is involved for both excitation modes. Also, a perfect quadratic dependence of laser power in the emission intensity function has been recorded. We tested the application of a small solid state green laser to two-photon induced time-resolved fluorescence, revealing the emission anisotropy of PPO to be considerably higher for two-photon than for one-photon excitation.
Collapse
Affiliation(s)
- Rafal Luchowski
- Address: Center for Commercialization of Fluorescence Technologies (CCFT), Department of Molecular Biology and Immunology, UNTHSC, Fort Worth, TX 76107, USA.
| |
Collapse
|
3
|
Luchowski R, Szabelski M, Sarkar P, Apicella E, Midde K, Raut S, Borejdo J, Gryczynski Z, Gryczynski I. Fluorescence instrument response standards in two-photon time-resolved spectroscopy. APPLIED SPECTROSCOPY 2010; 64:918-22. [PMID: 20719056 PMCID: PMC3038131 DOI: 10.1366/000370210792081000] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We studied the fluorescence properties of several potential picosecond lifetime standards suitable for two-photon excitation from a Ti:sapphire femtosecond laser. The fluorescence emission of the selected fluorophores (rose bengal, pyridine 1, and LDS 798) covered the visible to near-infrared wavelength range from 550 to 850 nm. We suggest that these compounds can be used to measure the appropriate instrument response functions needed for accurate deconvolution of fluorescence lifetime data. Lifetime measurements with multiphoton excitation that use scatterers as a reference may fail to properly resolve fluorescence intensity decays. This is because of the different sensitivities of photodetectors in different spectral regions. Also, detectors often lose sensitivity in the near-infrared region. We demonstrate that the proposed references allow a proper reconvolution of measured lifetimes. We believe that picosecond lifetime standards for two-photon excitation will find broad applications in multiphoton spectroscopy and in fluorescence lifetime imaging microscopy (FLIM).
Collapse
Affiliation(s)
- Rafal Luchowski
- Center for Commercialization of Fluorescence Technologies, Dept. of Molecular Biology & Immunology, UNTHSC, Fort Worth, Texas 76107, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Matveeva EG, Gryczynski I, Barnett A, Calander N, Gryczynski Z. Red blood cells do not attenuate the SPCE fluorescence in surface assays. Anal Bioanal Chem 2007; 388:1127-35. [PMID: 17534609 DOI: 10.1007/s00216-007-1322-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 04/11/2007] [Accepted: 04/24/2007] [Indexed: 12/19/2022]
Abstract
We describe the positive effect of surface plasmon-coupled fluorescence emission (SPCE) on the detection of a signal from a surface immunoassay in highly absorbing or/and scattering samples. A model immunoassay using fluorescently labeled anti-rabbit antibodies that bind to rabbit immunoglobulin on a silver surface was performed, and the signal was detected in the presence of various highly absorbing and/or scattering solutions or suspensions, such as hemoglobin solution, plastic beads, and red blood cells. The results showed that a highly absorbing solution consisting of small molecules (dye, hemoglobin) attenuates the SPCE signal approximately 2-3-fold. In contrast, suspensions with the same absorption containing large particles (large beads, red blood cell suspension) attenuate the SPCE signal only slightly, approximately 5-10%. Also, a suspension of large undyed, highly scattering beads does not reduce the SPCE signal. The effects on the immunoassay signal of the sample background absorption and scattering, the size of the background particles, and the geometry of the experimental set-up are discussed. We believe that SPCE is a promising technique in the development of biosensors utilized for surface-based assays, as well as any assays performed directly in highly absorbing and/or scattering solutions without washing or separation procedures. Figure Red blood cells (unlike hemoglobin) do not attenuate the SPCE fluorescence in surface assays.
Collapse
Affiliation(s)
- Evgenia G Matveeva
- Department of Molecular Biology and Immunology, University of North Texas, Health Science Center, Fort Worth, TX 76107, USA.
| | | | | | | | | |
Collapse
|
5
|
Aslan K, Malyn SN, Geddes CD. Microwave-Accelerated Surface Plasmon-Coupled Directional Luminescence: application to fast and sensitive assays in buffer, human serum and whole blood. J Immunol Methods 2007; 323:55-64. [PMID: 17407779 DOI: 10.1016/j.jim.2007.02.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 02/15/2007] [Accepted: 02/28/2007] [Indexed: 10/23/2022]
Abstract
The applicability of a new technique, Microwave-Accelerated Surface Plasmon-Coupled Luminescence (MA-SPCL) for fast and sensitive bioassays in buffer, serum and whole blood using quantum dots as luminescence reporters is demonstrated. In this regard, a model bioassay based on the well-known interactions of biotin and streptavidin is used. Using MA-SPCL, the bioassay was kinetically completed within 1 min with the use of low power microwave heating as compared to the identical bioassay which took in excess of 30 min to reach >95% completion at room temperature, a 30-fold increase in assay kinetics. The luminescence emission from the quantum dots was coupled to surface plasmons of the gold film, enabling the detection of the luminescence emission in a highly directional fashion as compared to the normal isotropic emission, for enhanced sensitivity and detection. The combined effect of microwaves for faster assay kinetics, with surface plasmon-coupled luminescence for sensitive luminescence measurements, has also made possible the demonstration of the use of the MA-SPCL technique for assays run in complex media, such as human serum and whole blood, where the same assay could not be performed at room temperature due to the coagulation of blood. In the MA-SPCL assay run in serum and whole blood, the luminescence intensity from 33 nM quantum dots was 75% and 20% that of the luminescence intensity from the assay run in buffer, with a signal to noise ratio of 12.5 and 3, respectively.
Collapse
Affiliation(s)
- Kadir Aslan
- Institute of Fluorescence, Laboratory for Advanced Medical Plasmonics, Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD, 21201, USA
| | | | | |
Collapse
|
6
|
Matveeva EG, Gryczynski I, Malicka J, Gryczynski Z, Goldys E, Howe J, Berndt KW, Lakowicz JR. Plastic versus glass support for an immunoassay on metal-coated surfaces in optically dense samples utilizing directional surface plasmon-coupled emission. J Fluoresc 2006; 15:865-71. [PMID: 16328701 PMCID: PMC6816260 DOI: 10.1007/s10895-005-0015-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We compared plastic (polycarbonate) and high-quality glass support materials for gold-coated slides, when performing a model immunoassay against rabbit IgG using fluorescently labeled (AlexaFluor-647) anti-rabbit IgG, and detecting surface plasmon-coupled emission (SPCE) signals. Both, glass and plastic slides were simultaneously coated with a 48-nm layer of gold and protected with a 10-nm layer of silica. The maximum SPCE signal of AlexaFluor-647 was only two- to three-fold smaller on plastic slides than on glass slides. A small difference in the SPCE angles on glass (theta (F) = 55 degrees ) and plastic (theta (F) = 52.5 degrees ) slides was observed and can be explained with a slightly smaller refractive index of the plastic. We have not found any difference in the angle distribution (sharpness of the fluorescence signal at optimal SPCE angle) for the plastic slide compared to the glass slide. The kinetics of binding was monitored on the plastic slide as well as on the glass slide. Optically dense samples, a 4% red blood cell suspension and a 15% hemoglobin solution, are causing a reduction in the immunoassay SPCE signal by approximately 15% and three times, respectively, and the percentage of the reduction is the same for plastic and for glass slides. We believe that plastic substrates can be readily used in any SPCE assay, with only marginally lower total signal compared to high-quality glass slides.
Collapse
Affiliation(s)
- Evgenia G Matveeva
- Center for Fluorescence Spectroscopy, University of Maryland at Baltimore, School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, USA.
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Matveeva EG, Gryczynski Z, Malicka J, Lukomska J, Makowiec S, Berndt KW, Lakowicz JR, Gryczynski I. Directional surface plasmon-coupled emission: application for an immunoassay in whole blood. Anal Biochem 2006; 344:161-7. [PMID: 16091280 PMCID: PMC6816263 DOI: 10.1016/j.ab.2005.07.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Revised: 07/01/2005] [Accepted: 07/06/2005] [Indexed: 12/31/2022]
Abstract
We present a new approach for performing fluorescence immunoassay in whole blood using fluorescently labeled anti-rabbit immunoglobulin G (IgG) on a silver surface. This approach, which is based on surface plasmon-coupled emission (SPCE), provides increased sensitivity and substantial background reduction due to exclusive selection of the signal from the fluorophores located near a bioaffinity surface. This article describes the effect of an optically dense sample matrix, namely human whole blood and serum, on the intensity of the SPCE. An antigen (rabbit IgG) was adsorbed to a slide covered with a thin silver metal layer, and the SPCE signal from the fluorophore-labeled anti-rabbit antibody, binding to the immobilized antigen, was detected. The effect of the sample matrix (buffer, human serum, or human whole blood) on the end-point immunoassay SPCE signal was studied. It was demonstrated that the kinetics of binding could be monitored directly in whole blood or serum. The results showed that human serum and human whole blood attenuate the SPCE end-point signal and the immunoassay kinetic signal only approximately two- and threefold, respectively, as compared with buffer, resulting in signals that are easily detectable even in whole blood. The high optical absorption of the hemoglobin can be tolerated because only fluorophores within a couple of hundred nanometers from the metallic film contribute to SPCE. Excited fluorophores outside the 200-nm layer do not contribute to SPCE, and their free space emission is not transmitted through the opaque metallic film into the glass substrate. We believe that SPCE has the potential of becoming a powerful approach for performing immunoassays based on surface-bound analytes or antibodies for many biomarkers directly in dense samples such as whole blood with no need for washing steps.
Collapse
Affiliation(s)
- Evgenia G Matveeva
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland at Baltimore, Baltimore, MD 21201, USA.
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Baker SN, Brauns EB, McCleskey TM, Burrell AK, Baker GA. Fluorescence quenching immunoassay performed in an ionic liquid. Chem Commun (Camb) 2006:2851-3. [PMID: 17007394 DOI: 10.1039/b606473f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe the first example of immunoanalysis performed within an ionic liquid with minimal deleterious effect; our results bode well for the development of second-generation biosensors, particularly in applications involving poorly water soluble analytes including pesticides, phospholipids, and illicit drugs.
Collapse
Affiliation(s)
- Sheila N Baker
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | | | | | | | | |
Collapse
|
9
|
Tirri ME, Huttunen RJ, Toivonen J, Härkönen PL, Soini JT, Hänninen PE. Two-photon excitation in fluorescence polarization receptor-ligand binding assay. ACTA ACUST UNITED AC 2005; 10:314-9. [PMID: 15964932 DOI: 10.1177/1087057104273334] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fluorescence polarization is one of the most commonly used homogeneous assay principles in drug discovery for screening of potential lead compounds. In this article, the fluorescence polarization technique is combined with 2-photon excitation of fluorescence. Theoretically, the use of 2-photon excitation of fluorescence increases the volumetric sensitivity and polarization contrast of fluorescence polarization assays. The work in this report demonstrates these predictions for an estrogen receptor ligand binding assay.
Collapse
Affiliation(s)
- Marko E Tirri
- Laboratory of Biophysics, Institute of Biomedicine, University of Turku, Finland.
| | | | | | | | | | | |
Collapse
|
10
|
Baker GA, Moore DS. Progress in plasmonic engineering of surface-enhanced Raman-scattering substrates toward ultra-trace analysis. Anal Bioanal Chem 2005; 382:1751-70. [PMID: 16049671 DOI: 10.1007/s00216-005-3353-7] [Citation(s) in RCA: 279] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 05/25/2005] [Indexed: 10/25/2022]
Abstract
This review describes advances made toward the application of surface-enhanced Raman scattering (SERS) in sensitive analysis and diagnostics. In the early sections of this review we briefly introduce the fundamentals of SERS including a discussion of SERS at the single-molecule level. Applications relevant to trace analysis, environmental monitoring, and homeland security and defense, for example high explosives and contaminant detection, are emphasized. Because the key to wider application of SERS analysis lies in the development of highly enhancing substrates, in the second half of the review we focus our attention on the extensive progress made in designing innovative soluble, supported, and ordered SERS-active nano-architectures to harness the potential of this technique toward solving current and emerging analytical tasks. No attempt or claim is made to review the field exhaustively in its entirety nor to cover all applications, but only to describe several significant milestones and progress made in these important areas and to provide some perspective on where the field is quickly moving.
Collapse
Affiliation(s)
- Gary A Baker
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | |
Collapse
|
11
|
Lakowicz JR, Malicka J, Matveeva E, Gryczynski I, Gryczynski Z. Plasmonic technology: novel approach to ultrasensitive immunoassays. Clin Chem 2005; 51:1914-22. [PMID: 16055432 PMCID: PMC2763913 DOI: 10.1373/clinchem.2005.053199] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
At the Center for Fluorescence Spectroscopy, we have taken advantage of the favorable properties of surface plasmon-coupled emission (SPCE) to improve fluorescence-based immunoassays. SPCE occurs when excited fluorophores near conducting metallic structures efficiently couple to surface plasmons. These surface plasmons, appearing as free electron oscillations in the metallic layer, produce electromagnetic radiation that preserves the spectral properties of fluorophores but is highly polarized and directional. SPCE immunoassays provide several advantages over other fluorescence-based methods. This review explains new approaches to fluorescence immunoassays, including our own use of SPCE for simultaneous detection of more than one fluorescent marker and performance of immunoassays in the presence of an optically dense medium, such as whole blood.
Collapse
Affiliation(s)
- Joseph R Lakowicz
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | | | | | | | | |
Collapse
|
12
|
Belfield KD, Bondar MV, Hales JM, Morales AR, Przhonska OV, Schafer KJ. One- and two-photon fluorescence anisotropy of selected fluorene derivatives. J Fluoresc 2005; 15:3-11. [PMID: 15711871 DOI: 10.1007/s10895-005-0207-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 09/15/2004] [Indexed: 10/25/2022]
Abstract
The steady-state excitation anisotropy spectra of fluorene derivatives were measured in viscous solvents, under the one- and two-photon excitation, over a broad spectral range (UV-Visible). The orientation of their absorption transition moments for the first, S0 --> S1, and second, S0 --> S2, excited states were determined. It was shown experimentally that a decrease in the angle between S0 --> S1 and S0 --> S2 transitions corresponded to an increased value of two-photon absorption (2PA) cross section for these molecules. Two-photon excitation anisotropy was nearly constant over the spectral region investigated (in contrast to one-photon excitation anisotropy spectra) and can be roughly explained by a simple model of 2PA based on the single intermediate state approximation. For comparison, the same trend in two-photon excitation anisotropy was observed for Rhodamine B in glycerol.
Collapse
Affiliation(s)
- K D Belfield
- Department of Chemistry, University of Central Florida, Orlando, Florida, USA.
| | | | | | | | | | | |
Collapse
|
13
|
Wang X, Kong X, Shan G, Yu Y, Sun Y, Feng L, Chao K, Lu S, Li Y. Luminescence Spectroscopy and Visible Upconversion Properties of Er3+ in ZnO Nanocrystals. J Phys Chem B 2004. [DOI: 10.1021/jp048021t] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xin Wang
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Xianggui Kong
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Guiye Shan
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Yi Yu
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Yajian Sun
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Liyun Feng
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Kefu Chao
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Shaozhe Lu
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Yajun Li
- Key Laboratory of Excited-State Process, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| |
Collapse
|
14
|
Matveeva E, Gryczynski Z, Gryczynski I, Malicka J, Lakowicz JR. Myoglobin immunoassay utilizing directional surface plasmon-coupled emission. Anal Chem 2004; 76:6287-92. [PMID: 15516120 PMCID: PMC6848856 DOI: 10.1021/ac0491612] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We described an immunoassay for the cardiac marker myoglobin on a thin silver mirror surface using surface plasmon-coupled emission (SPCE). SPCE occurs for fluorophores in proximity (within approximately 200 nm) of a thin metal film (in our case, silver) and results in a highly directional radiation through a glass substrate at a well-defined angle from the normal axis. We used the effect of SPCE to develop a myoglobin immunoassay on the silver mirror surface deposited on a glass substrate. Binding of the labeled anti-myoglobin antibodies led to the enhanced fluorescence emission at a specific angle of 72 degrees . The directional and enhanced directional fluorescence emission enables detection of myoglobin over a wide range of concentrations from subnormal to the elevated level of this cardiac marker. Utilizing SPCE allowed us also to demonstrate significant background suppression (from serum or whole blood) in the myoglobin immunoassay. We expect SPCE to become a powerful technique for performing immunoassays for many biomarkers in surface-bound assays.
Collapse
Affiliation(s)
- Evgenia Matveeva
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Zygmunt Gryczynski
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Ignacy Gryczynski
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Joanna Malicka
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Joseph R. Lakowicz
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, Maryland 21201
| |
Collapse
|
15
|
Reyes DR, Perruccio EM, Becerra SP, Locascio LE, Gaitan M. Micropatterning neuronal cells on polyelectrolyte multilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:8805-8811. [PMID: 15379510 DOI: 10.1021/la049249a] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper describes an approach to adhere retinal cells on micropatterned polyelectrolyte multilayer (PEM) lines adsorbed on poly(dimethylsiloxane) (PDMS) surfaces using microfluidic networks. PEMs were patterned on flat, oxidized PDMS surfaces by sequentially flowing polyions through a microchannel network that was placed in contact with the PDMS surface. Polyethyleneimine (PEI) and poly(allylamine hydrochloride) (PAH) were the polyions used as the top layer cellular adhesion material. The microfluidic network was lifted off after the patterning was completed and retinal cells were seeded on the PEM/PDMS surfaces. The traditional practice of using blocking agents to prevent the adhesion of cells on unpatterned areas was avoided by allowing the PDMS surface to return to its uncharged state after the patterning was completed. The adhesion of rat retinal cells on the patterned PEMs was observed 5 h after seeding. Cell viability and morphology on the patterned PEMs were assayed. These materials proved to be nontoxic to the cells used in this study regardless of the number of stacked PEM layers. Phalloidin staining of the cytoskeleton revealed no apparent morphological differences in retinal cells compared with those plated on polystyrene or the larger regions of PEI and PAH; however, cells were relatively more elongated when cultured on the PEM lines. Cell-to-cell communication between cells on adjacent PEM lines was observed as interconnecting tubes containing actin that were a few hundred nanometers in diameter and up to 55 microm in length. This approach provides a simple, fast, and inexpensive method of patterning cells onto micrometer-scale features.
Collapse
Affiliation(s)
- Darwin R Reyes
- Semiconductor Electronics Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899-8120, USA.
| | | | | | | | | |
Collapse
|
16
|
Bukowski EJ, Bright FV. Minimizing urine autofluorescence under multi-photon excitation conditions. APPLIED SPECTROSCOPY 2004; 58:1101-1105. [PMID: 15479527 DOI: 10.1366/0003702041959442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report on the effects of excitation wavelength, laser power, and phase resolution on the multi-photon-excited autofluorescence (background) from human urine. When compared to the autofluorescence under one-photon excitation conditions (lambda(ex) = 260-480 nm), the urine multi-photon-excited autofluorescence (lambda(ex) = 725-950 nm) can be less complicated. However, at higher laser powers, the multi-photon-excited autofluorescence spectra that are produced by excitation above ~775 nm are more complex in comparison to the corresponding one-photon-excited autofluorescence. The origin of these more complex spectra arises from simultaneous two- and three-photon-driven excitation of intrinsic luminescent species within the urine. At lower laser powers, three-photon-driven processes are minimized and the autofluorescence spectrum is simplified. Phase resolution is used to further minimize the urine autofluorescence, but it cannot fully eliminate autofluorescence even when excitation is performed under multi-photon conditions at 950 nm. For detecting 250 nM Rhodamine 6G (a mock analyte) dissolved in urine, we find that the two-photon excitation is superior in comparison to one-photon excitation by 5- to 70-fold, depending on the excitation wavelength. Phase resolution combined with two-photon excitation leads to an additional 5- to 7-fold improvement in signal-to-background ratios in comparison to steady-state two-photon excitation.
Collapse
Affiliation(s)
- Eric J Bukowski
- Department of Chemistry, Natural Sciences Complex, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
| | | |
Collapse
|
17
|
Zhou X, Ren AM, Feng JK, Liu XJ. Studies on the two-photon absorption properties of trigonal dehydrobenzo[18]annulenes. CAN J CHEM 2004. [DOI: 10.1139/v04-086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The one-photon and two-photon absorption properties of donoracceptor substituted dehydrobenzo[18]annulenes were determined by using density functional theory and ZINDO methods. The macrocycle containing C2v symmetry exhibited the largest TPA cross-section value of 3376 × 1050 cm4 s/photon. The calculated results indicate that the TPA response in the whole molecule comes from the contribution of that in the every side in the trigon. It is notable that the magnitudes of the transition dipole moment from the virtual intermediate state to the TPA final state and the dipole moment difference between the ground state and the virtual intermediate state play important roles in increasing the TPA cross-section value. This series of molecules can circumvent the trade-off between efficiency and transparency, and they provide a promising direction for the further development of novel two-dimensional molecules with such properties.Key words: two-photon absorption, ZINDO, sum-over-states, dehydrobenzo[18] annulenes, transparency.
Collapse
|
18
|
Matveeva E, Gryczynski Z, Gryczynski I, Lakowicz JR. Immunoassays based on directional surface plasmon-coupled emission. J Immunol Methods 2004; 286:133-40. [PMID: 15087228 PMCID: PMC2737394 DOI: 10.1016/j.jim.2003.12.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Accepted: 12/16/2003] [Indexed: 11/18/2022]
Abstract
We described a new approach to immunoassays using surface plasmon-coupled emission (SPCE). Fluorescence is visually isotropic in space, so that the sensitivity is limited in part by the light collection efficiency. By the use of SPCE, we can efficiently collect the emission and convert it to a cone-like directional beam in a glass substrate. SPCE is the coupling of excited fluorophores with a thin metal film, resulting in radiation of surface plasmons into the higher refractive index media. We used SPCE to develop a model affinity assay using labeled goat anti-rabbit immunoglobulin G (IgG) antibodies against rabbit IgG bound to a 50-nm-thick silver film. Binding of labeled IgG to the surface resulted in increased intensity observed at an angle of 75 degrees from the normal in the glass substrate. The SPCE intensity depends on proximity of the fluorophore to the silver film and does not require a change in quantum yield upon binding. The use of SPCE is shown to provide background suppression because excited fluorophores distant from the silver film do not result in SPCE. Sensitivity and selectivity can be further increased by excitation under conditions of surface plasmon resonance (SPR) because the evanescent field is enhanced by the resonance interaction and excitation is limited to the region near the metal. We believe SPCE will provide a new technology for high sensitivity and selectivity in surface-bound assays and microfluidic systems.
Collapse
Affiliation(s)
- Evgenia Matveeva
- Department of Biochemistry and Molecular Biology, Center for Fluorescence Spectroscopy, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, MD 21201, USA.
| | | | | | | |
Collapse
|
19
|
Synthesis and structure–photophysical property relationships for two coumarinyl-based two-photon induced fluorescent molecules. J Mol Struct 2003. [DOI: 10.1016/s0022-2860(03)00427-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
20
|
Iwase Y, Kamada K, Ohta K, Kondo K. Synthesis and photophysical properties of new two-photon absorption chromophores containing a diacetylene moiety as the central π-bridge. ACTA ACUST UNITED AC 2003. [DOI: 10.1039/b211268j] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
21
|
Hatzidakis GI, Tsatsakis AM, Krambovitis EK, Spyros A, Eremin SA. Use of L-lysine fluorescence derivatives as tracers to enhance the performance of polarization fluoroimmunoassays. A study using two herbicides as model antigens. Anal Chem 2002; 74:2513-21. [PMID: 12069231 DOI: 10.1021/ac011051x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescence polarization immunoassay (FPIA) is a convenient homogeneous assay, the use of which is restricted in environmental analysis by low sensitivity and matrix effects. We selected the herbicides 2,4D and 2,4,5T to synthesize new L-lysine-based fluorescent tracers using solid-phase chemistry. In addition, three different immunogens of 2,4,5T were prepared for immunization and antibody production. The new tracers and antibodies were adapted to FPIA. Tracers with the hapten attached to the alpha-aminogroup of L-lysine and fluorescein to the e-amino group exhibited at least a 5-fold increased sensitivity when compared to the previously reported ethylenediamine-based tracer (2,4D-EDA-F). The isomeric structure (hapten attached to the e-amino and fluorescein to the alpha-amino group) appeared 7.6 times less sensitive, and all other alternative structures exhibited even lower sensitivities. This observation was confirmed against the monoclonal anti-2,4D antibody E2/G2 and polyclonal anti-2,4,5T antibodies. The affinity constant of 2,4D-EDA-F with E2/G2 was 8.1 times higher when compared with the new tracer, suggesting the more specific nature of the L-lysine-based tracer, the use of which leads to a more sensitive assay. This type of tracer could improve performance and lower substantially the detection limits of FPIAs.
Collapse
Affiliation(s)
- George I Hatzidakis
- Laboratory of Toxicology, Medical School, University of Crete, Heraklion, Greece.
| | | | | | | | | |
Collapse
|
22
|
Johnson DK, Combs SM, Parsen JD, Jolley ME. Lead analysis by anti-chelate fluorescence polarization immunoassay. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2002; 36:1042-1047. [PMID: 11917989 DOI: 10.1021/es011114t] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Lead concentrations were determined by a fluorescence polarization immunoassay (FPIA) method that uses polyclonal antibodies raised against the lead(II) chelate of ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA). The technique is based on competition for a fixed concentration of antibody binding sites between Pb-EDTA, formed by treating the sample with excess EDTA, and a fixed concentration of a fluorescent analogue of the Pb-EDTA complex. The objective was to correlate results obtained by FPIA with those produced by conventional atomic spectroscopy analysis of soils, solid waste leachates (produced by the Toxicity Characteristic Leachate Procedure; TCLP), airborne dust, and drinking water. Linear regression analysis of FPIA results for 138 soil samples containing 0-3094 ppm Pb(II) by flame atomic absorption spectroscopy and 40 TCLP extracts containing 0-668 ppm Pb(II) by inductively coupled plasma atomic emission spectroscopy produced correlation coefficients (r2) of 0.96 and 0.93, respectively. Pilot studies of mineral acid extracts of airborne dust trapped on fiberglass filters and of two sources of drinking water demonstrated the feasibility of also measuring lead in these matrixes by FPIA. The limit of detection under conditions that minimized sample dilution was approximately 1 ppb, and cross reactivity with 15 nontarget metals was below 0.5% in all cases. The methods are simple to perform and are amenable to field testing and mobile laboratory use, allowing timely and cost-effective characterization of suspected sources of lead contamination.
Collapse
|
23
|
Gryczynski I, Piszczek G, Gryczynski Z, Lakowicz JR. Four-Photon Excitation of 2,2'-Dimethyl- p-terphenyl. J Phys Chem A 2002; 106:754-759. [PMID: 32009775 DOI: 10.1021/jp012860n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the emission spectra, intensity decays, and anisotropy decay of 2,2'-dimethyl-p-terphenyl (DMT) with four-photon excitation. When excited with a fs Ti:Sapphire laser the emission intensity of DMT was found to depend on the third power of the incident intensity for excitation of 783 nm, and on the fourth power of the incident intensity for excitation at 882 nm. Surprisingly, at the highest value incident power, the emission intensity for four-photon excitation was about 10-fold less than with three-photon excitation. The emission spectra, intensity decays and correlation times were found to be identical for three- and four-photon excitation. However, the fundamental anisotropy (r 0) of DMT depended on the mode of excitation. To the best of our knowledge, the r 0 value of 0.70 is the highest ever observed for an isotropic solution. These results suggest that four-photon excitation can be used with red-NIR lasers to obtain excitation of UV-absorbing chromophores.
Collapse
Affiliation(s)
- Ignacy Gryczynski
- University of Maryland Baltimore, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Grzegorz Piszczek
- University of Maryland Baltimore, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Zygmunt Gryczynski
- University of Maryland Baltimore, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Joseph R Lakowicz
- University of Maryland Baltimore, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201
| |
Collapse
|
24
|
Abstract
From its conception a decade ago, multiphoton microscopy has evolved from a photonic novelty to an indispensable tool for gleaning information from subcellular events within organized tissue environments. Its relatively deep optical penetration has recently been exploited for subcellularly resolved investigations of disease models in living transgenic mice. Its enhanced spectral accessibility enables aberration-free imaging of fluorescent molecules absorbing in deep-UV energy regimes with simultaneous imaging of species having extremely diverse emission spectra. Although excited fluorescence is the primary signal for multiphoton microscopy, harmonic generation by multiphoton scattering processes are also valuable for imaging species with large anharmonic modes, such as collagen structures and membrane potential sensing dyes.
Collapse
Affiliation(s)
- R M Williams
- Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
| | | | | |
Collapse
|