title: Open micro-fluidic system for atomic force microscopy-guided in situ electrochemical probing of a single cell.
abstract: Ultra-sharp nano-probes and customized atomic force microscopy (AFM) have previously been developed in our laboratory for in situ sub-cellular probing of electrochemical phenomena in living plant cells during their photosynthesis. However, this AFM-based electrochemical probing still has numerous engineering challenges such as immobilization of the live cells, compatibility of the immobilization procedure with AFM manipulation of the probe, maintenance of biological activity of the cells for an extended time while performing the measurements, and minimization of electrochemical noise. Thus, we have developed an open micro-fluidic channel system (OMFC) in which individual cells can be immobilized in micro-traps by capillary flow. This system affords easy AFM access and allows for maintenance of the cells in a well-defined chemical environment, which sustains their biological activity. The use of micro-channels for making the electrochemical measurements significantly reduces parasitic electrical capacitances and allows for current detection in the sub-pico-ampere range at high signal bandwidths. The OMFC was further studied using simulation packages for optimal design conditions. This system was successfully used to measure light-dependent oxidation currents of a few pico-amperes from the green alga Chlamydomonas reinhardtii.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA. whryu@stanford.edu
authors.forename: Wonhyoung
authors.initials: W
authors.lastname: Ryu
authors.forename: Zubin
authors.initials: Z
authors.lastname: Huang
authors.forename: Joong
authors.initials: J
authors.lastname: Sun Park
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Moseley
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Grossman
authors.forename: Rainer J
authors.initials: RJ
authors.lastname: Fasching
authors.forename: Fritz B
authors.initials: FB
authors.lastname: Prinz
mesh_terms: D002477:Cells / Q000737:chemistry* / Q000648:ultrastructure*; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D018625:Microscopy, Atomic Force / Q000295:instrumentation* / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction
chemical_list: D006046:Gold