title: Protein preconcentration using nanofractures generated by nanoparticle-assisted electric breakdown at junction gaps.
abstract: Sample preconcentration is an important step that increases the accuracy of subsequent detection, especially for samples with extremely low concentrations. Due to the overlapping of electrical double layers in the nanofluidic channel, the concentration polarization effect can be generated by applying an electric field. Therefore, a nonlinear electrokinetic flow is induced, which results in the fast accumulation of proteins in front of the induced ionic depletion zone, the so-called exclusion-enrichment effect. Nanofractures were created in this work to preconcentrate proteins via the exclusion-enrichment effect. The protein sample was driven by electroosmotic flow and accumulated at a specific location. The preconcentration chip for proteins was fabricated using simple standard soft lithography with a polydimethylsiloxane replica. Nanofractures were formed by utilizing nanoparticle-assisted electric breakdown. The proposed method for nanofracture formation that utilizes nanoparticle deposition at the junction gap between microchannels greatly decreases the required electric breakdown voltage. The experimental results indicate that a protein sample with an extremely low concentration of 1 nM was concentrated to 1.5×10(4)-fold in 60 min using the proposed chip.
authors.affiliation: Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia Yi, Taiwan, R.O.C.
authors.forename: Chun-Ping
authors.initials: CP
authors.lastname: Jen
authors.affiliation: Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia.
authors.forename: Tamara G
authors.initials: TG
authors.lastname: Amstislavskaya
authors.affiliation: Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia Yi, Taiwan, R.O.C.
authors.forename: Chen-Chi
authors.initials: CC
authors.lastname: Kuo
authors.affiliation: Department of Medicine, National Cheng-Kung University, Tainan, Taiwan, R.O.C.; Department of Biochemistry and Molecular Biology, National Cheng-Kung University, Tainan, Taiwan, R.O.C.
authors.forename: Yu-Hung
authors.initials: YH
authors.lastname: Chen
mesh_terms: D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins