Combined optical trapping and single-molecule fluorescence
<p>Abstract</p> <p>Background</p> <p>Two of the mainstay techniques in single-molecule research are optical trapping and single-molecule fluorescence. Previous attempts to combine these techniques in a single experiment – and on a single macromolecule of interest – have...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2003-02-01
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| Series: | Journal of Biology |
| Online Access: | http://jbiol.com/content/2/1/6 |
| _version_ | 1811310488844238848 |
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| author | Lang Matthew J Fordyce Polly M Block Steven M |
| author_facet | Lang Matthew J Fordyce Polly M Block Steven M |
| author_sort | Lang Matthew J |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Two of the mainstay techniques in single-molecule research are optical trapping and single-molecule fluorescence. Previous attempts to combine these techniques in a single experiment – and on a single macromolecule of interest – have met with little success, because the light intensity within an optical trap is more than ten orders of magnitude greater than the light emitted by a single fluorophore. Instead, the two techniques have been employed sequentially, or spatially separated by distances of several micrometers within the sample, imposing experimental restrictions that limit the utility of the combined method. Here, we report the development of an instrument capable of true, simultaneous, spatially coincident optical trapping and single-molecule fluorescence.</p> <p>Results</p> <p>We demonstrate the capability of the apparatus by studying force-induced strand separation of a rhodamine-labeled, 15 base-pair segment of double-stranded DNA, with force applied perpendicular to the axis of the DNA molecule. As expected, we observed abrupt mechanical transitions corresponding to the unzipping of DNA at a critical force. Transitions occurred concomitant with changes in the fluorescence of dyes attached at the duplex ends, which became unquenched upon strand separation.</p> <p>Conclusions</p> <p>Through careful optical design, the use of high-performance spectral notch filters, a judicious choice of fluorophores, and the rapid acquisition of data gained by computer-automating the experiment, it is possible to perform combined optical trapping and single-molecule fluorescence. This opens the door to many types of experiment that employ optical traps to supply controlled external loads while fluorescent molecules report concurrent information about macromolecular structure.</p> |
| first_indexed | 2024-04-13T09:59:39Z |
| format | Article |
| id | doaj.art-9328802fc1f147cda682349a6378e30f |
| institution | Directory Open Access Journal |
| issn | 1478-5854 1475-4924 |
| language | English |
| last_indexed | 2024-04-13T09:59:39Z |
| publishDate | 2003-02-01 |
| publisher | BMC |
| record_format | Article |
| series | Journal of Biology |
| spelling | doaj.art-9328802fc1f147cda682349a6378e30f2022-12-22T02:51:16ZengBMCJournal of Biology1478-58541475-49242003-02-0121610.1186/1475-4924-2-6Combined optical trapping and single-molecule fluorescenceLang Matthew JFordyce Polly MBlock Steven M<p>Abstract</p> <p>Background</p> <p>Two of the mainstay techniques in single-molecule research are optical trapping and single-molecule fluorescence. Previous attempts to combine these techniques in a single experiment – and on a single macromolecule of interest – have met with little success, because the light intensity within an optical trap is more than ten orders of magnitude greater than the light emitted by a single fluorophore. Instead, the two techniques have been employed sequentially, or spatially separated by distances of several micrometers within the sample, imposing experimental restrictions that limit the utility of the combined method. Here, we report the development of an instrument capable of true, simultaneous, spatially coincident optical trapping and single-molecule fluorescence.</p> <p>Results</p> <p>We demonstrate the capability of the apparatus by studying force-induced strand separation of a rhodamine-labeled, 15 base-pair segment of double-stranded DNA, with force applied perpendicular to the axis of the DNA molecule. As expected, we observed abrupt mechanical transitions corresponding to the unzipping of DNA at a critical force. Transitions occurred concomitant with changes in the fluorescence of dyes attached at the duplex ends, which became unquenched upon strand separation.</p> <p>Conclusions</p> <p>Through careful optical design, the use of high-performance spectral notch filters, a judicious choice of fluorophores, and the rapid acquisition of data gained by computer-automating the experiment, it is possible to perform combined optical trapping and single-molecule fluorescence. This opens the door to many types of experiment that employ optical traps to supply controlled external loads while fluorescent molecules report concurrent information about macromolecular structure.</p>http://jbiol.com/content/2/1/6 |
| spellingShingle | Lang Matthew J Fordyce Polly M Block Steven M Combined optical trapping and single-molecule fluorescence Journal of Biology |
| title | Combined optical trapping and single-molecule fluorescence |
| title_full | Combined optical trapping and single-molecule fluorescence |
| title_fullStr | Combined optical trapping and single-molecule fluorescence |
| title_full_unstemmed | Combined optical trapping and single-molecule fluorescence |
| title_short | Combined optical trapping and single-molecule fluorescence |
| title_sort | combined optical trapping and single molecule fluorescence |
| url | http://jbiol.com/content/2/1/6 |
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