Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Combined optical trapping and single-molecule fluorescence. | J. Biol. Journal of Biology BioMed Central Research article Combined optical trapping and single-molecule fluorescence Matthew J Lang fC Polly M Fordyce and Steven M Block t Addresses Department of Biological Sciences tDepartment of Applied Physics and Department of Physics Stanford University Stanford CA 94305-5020 USA. Current address Biological Engineering Division and Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA. Correspondence Steven M Block. E-mail sblock@ Published 24 February 2003 Received 24 December 2002 Journal of Biology 2003 2 6 R d 3 .2003 J I gy Accepted 4 February 2003 The electronic version of this article is the complete one and can be found online at http content 2 l 6 2003 Lang et al. licensee BioMed Central Ltd. This is an Open Access article verbatim copying and redistribution of this article are permitted in all media for any purpose provided this notice is preserved along with the article s original URL. Abstract Background 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. Results 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 .
