Ultrahigh-resolution optical trap with single-fluorophore sensitivity

Matthew J. Comstock, Taekjip Ha, Yann R. Chemla

Research output: Contribution to journalArticlepeer-review


We present a single-molecule instrument that combines a time-shared ultrahigh-resolution dual optical trap interlaced with a confocal fluorescence microscope. In a demonstration experiment, we observed individual single fluorophore-labeled DNA oligonucleotides to bind and unbind complementary DNA suspended between two trapped beads. Simultaneous with the single-fluorophore detection, we clearly observed coincident angstrom-scale changes in tether extension. Fluorescence readout allowed us to determine the duplex melting rate as a function of force. The new instrument will enable the simultaneous measurement of angstrom-scale mechanical motion of individual DNA-binding proteins (for example, single-base-pair stepping of DNA translocases) along with the detection of properties of fluorescently labeled protein (for example, internal configuration).

Original languageEnglish (US)
Pages (from-to)335-340
Number of pages6
JournalNature Methods
Issue number4
StatePublished - Apr 2011

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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