title: Injection of ultrasmall samples and single molecules into tapered capillaries.
abstract: A novel injection scheme is described in which ultrasmall samples in the attoliter (10(-18) L) and low femtoliter (10(-15) L) range, or even single molecules, are controllably introduced into a tapered capillary so that electrophoretic separation can be carried out. To match the dimensions of the capillary inlet with that of the sample, capillary tips are tapered to an inside diameter ranging from hundreds of nanometers to a few micrometers. To inject an ultrasmall sample, optical trapping is used to immobilize and manipulate the sample in order to place it inside or next to the capillary inlet. A small controlled suction results in the loading of the sample into the capillary.
authors.affiliation: Department of Chemistry, Stanford University, California 94305-5080, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Chiu
authors.forename: A
authors.initials: A
authors.lastname: Hsiao
authors.forename: A
authors.initials: A
authors.lastname: Gaggar
authors.forename: R A
authors.initials: RA
authors.lastname: Garza-López
authors.forename: O
authors.initials: O
authors.lastname: Orwar
authors.forename: R N
authors.initials: RN
authors.lastname: Zare
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods*; D004247:DNA / Q000737:chemistry; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods
chemical_list: D004247:DNA