title: Dielectrophoretic concentration of low-abundance nanoparticles using a nanostructured tip.
abstract: Electric field-induced concentration has the potential for application in highly sensitive detection of nanoparticles (NPs) for disease diagnosis and drug discovery. Conventional two-dimensional planar electrodes, however, have shown limited sensitivity in NP concentration. In this paper, the dielectrophoretic (DEP) concentration of low-abundance NPs is studied using a nanostructured tip where a high electric field of 3 × 10(7) V m(-1) is generated. In experimental studies, individual 2, 10, and 100 nm Au NPs are concentrated to a nanotip using DEP concentration and are detected by scanning transmission and scanning electron microscopes. The DEP force on Au NPs near the end of a nanotip is computed according to the distance, and then compared with Brownian motion-induced force. The computational study shows qualitative agreement with the experimental results. When the experimental conditions for DEP concentration are optimized for 8 nm-long oligonucleotides, the sensitivity of a nanotip is 10 aM (10 attomolar; nine copies in a 1.5 μl sample volume). This DEP concentrator using a nanotip can be used for molecular detection without amplification.
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
authors.forename: Woon-Hong
authors.initials: WH
authors.lastname: Yeo
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Kopacz
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Xinqi
authors.initials: X
authors.lastname: Chen
authors.forename: Jinsong
authors.initials: J
authors.lastname: Wu
authors.forename: Dayong
authors.initials: D
authors.lastname: Gao
authors.forename: Kyong-Hoon
authors.initials: KH
authors.lastname: Lee
authors.forename: Wing-Kam
authors.initials: WK
authors.lastname: Liu
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Chung
mesh_terms: D004560:Electricity; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D009841:Oligonucleotides / Q000302:isolation & purification*; D010316:Particle Size
chemical_list: D009841:Oligonucleotides; D006046:Gold