title: Fabrication of PMMA nanofluidic electrochemical chips with integrated microelectrodes.
abstract: A novel method based on plasma etching was proposed for monolithically integrating planar nanochannels and microelectrodes on a poly (methyl methacrylate) (PMMA) plate, and complete PMMA nanofluidic electrochemical chips with integrated microelectrodes were constructed by bonding with another PMMA plate containing microchannels. The fabrication sequences of nanochannels and microelectrodes were optimized. The oxygen plasma etching rate of PMMA nanochannels was studied, and the average rate was 15 nm/min under optimal conditions. An UV-ozone assisted thermal bonding method was developed to realize a low-temperature chip bonding, and the variations in width and depth of nanochannels before and after bonding were 2% and 5%, respectively. As a demonstration, a nanoparticle crystal (NPC)-based nanofluidic biosensor with integrated Ag microelectrodes was designed and fabricated. Sub-microchannel arrays with a depth of 400 nm and a width of 30 μm on the biosensor functioned as filters, and trapped 540 nm silica nanoparticles modified with streptavidin inside the connected microchannel to assemble the NPC. The interspaces in the NPC formed a three-dimensional nanochannel network with an equivalent diameter of 81 nm. By measuring the conductance across the NPC, a high quality nanofluidic sensing of biotin was achieved. The limit of detection was 1 aM, and the detection range was from 1 aM to 0.1 nM.
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China. Electronic address: liujs@dlut.edu.cn.
authors.forename: Junshan
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Microelectronics, Peking University, Beijing 100871, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ouyang
authors.affiliation: Institute of Microelectronics, Peking University, Beijing 100871, China; National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Peking University, Beijing 100871, China. Electronic address: w.wang@pku.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Shenbo
authors.initials: S
authors.lastname: Xu
authors.affiliation: Chemical Engineering School, Dalian University of Technology, Dalian 116024, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Ge
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Longchang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Chong
authors.initials: C
authors.lastname: Liu
authors.affiliation: Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116024, China.
authors.forename: Liding
authors.initials: L
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D001710:Biotin / Q000032:analysis; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D055616:Microtechnology; D049329:Nanostructures / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D001710:Biotin; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate
keywords: Biosensor; Electrochemical detection; Microelectrode; Nanofluidic; PMMA