title: Yoctoliter thermometry for single-molecule investigations: a generic bead-on-a-tip temperature-control module.
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.
authors.affiliation: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242 (USA).
authors.forename: Deepak
authors.initials: D
authors.lastname: Koirala
authors.forename: Jibin Abraham
authors.initials: JA
authors.lastname: Punnoose
authors.forename: Prakash
authors.initials: P
authors.lastname: Shrestha
authors.forename: Hanbin
authors.initials: H
authors.lastname: Mao
mesh_terms: D036103:Nanotechnology / Q000379:methods*; D052898:Optical Tweezers / Q000627:therapeutic use*; D013696:Temperature; D013816:Thermodynamics; D062125:Thermometry / Q000379:methods*
keywords: mechanochemical properties; optical tweezers; single-molecule studies; temperature jump; thermometry