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Yoctoliter Thermometry for Single‐Molecule Investigations: A Generic Bead‐on‐a‐Tip Temperature‐Control Module
Author(s) -
Koirala Deepak,
Punnoose Jibin Abraham,
Shrestha Prakash,
Mao Hanbin
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201310172
Subject(s) - temperature jump , optical tweezers , molecule , jump , thermometer , bead , particle (ecology) , photothermal therapy , materials science , nanotechnology , laser , microsecond , chemical physics , chemistry , optics , thermodynamics , physics , composite material , oceanography , organic chemistry , quantum mechanics , geology
Abstract A new temperature‐jump (T‐jump) strategy avoids photo‐damage of individual molecules by focusing a low‐intensity laser on a black microparticle at the tip of a capillary. The black particle produces an efficient photothermal effect that enables a wide selection of lasers with powers in the milliwatt range to achieve a T‐jump of 65 °C within milliseconds. To measure the temperature in situ in single‐molecule experiments, the temperature‐dependent mechanical unfolding of a single DNA hairpin molecule was monitored by optical tweezers within a yoctoliter volume. Using this bead‐on‐a‐tip module and the robust single‐molecule thermometer, full thermodynamic landscapes for the unfolding of this DNA hairpin were retrieved. These approaches are likely to provide powerful tools for the microanalytical investigation of dynamic processes with a combination of T‐jump and single‐molecule techniques.