title: Nanomechanical detection of DNA melting on microcantilever surfaces.
abstract: We observe surface stress changes in response to thermal dehybridization, or melting, of double-stranded DNA (dsDNA) oligonucleotides that are grafted on one side of a microcantilever beam. Changes in surface stress occur when one complementary DNA strand melts and diffuses away from the other, resulting in alterations of the electrostatic, counterionic, and hydration interaction forces between the remaining neighboring surface-grafted DNA molecules. We have been able to distinguish changes in the melting temperature of dsDNA as a function of salt concentration and oligomer length. This technique also highlights differences between surface immobilized and solution DNA melting dynamics, which allows us to better understand the stability of DNA on surfaces. The transduction of phase transitions into a mechanical signal is ubiquitous for DNA, making cantilever-based detection a widely useful and complementary alternative to calorimetric and fluorescence measurements.
authors.affiliation: Department of Mechanical Engineering, UC Berkeley, Berkeley, California 94720, USA.
authors.forename: Sibani Lisa
authors.initials: SL
authors.lastname: Biswal
authors.forename: Digvijay
authors.initials: D
authors.lastname: Raorane
authors.forename: Alison
authors.initials: A
authors.lastname: Chaiken
authors.forename: Henryk
authors.initials: H
authors.lastname: Birecki
authors.forename: Arun
authors.initials: A
authors.lastname: Majumdar
mesh_terms: D004247:DNA / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D015342:DNA Probes / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000379:methods*; D009691:Nucleic Acid Denaturation; D055672:Static Electricity; D013499:Surface Properties; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D015342:DNA Probes; D004247:DNA