title: Non-Faradaic Electrochemical Detection of Exocytosis from Mast and Chromaffin Cells Using Floating-Gate MOS Transistors.
abstract: We present non-faradaic electrochemical recordings of exocytosis from populations of mast and chromaffin cells using chemoreceptive neuron MOS (CνMOS) transistors. In comparison to previous cell-FET-biosensors, the CνMOS features control (CG), sensing (SG) and floating gates (FG), allows the quiescent point to be independently controlled, is CMOS compatible and physically isolates the transistor channel from the electrolyte for stable long-term recordings. We measured exocytosis from RBL-2H3 mast cells sensitized by IgE (bound to high-affinity surface receptors FcεRI) and stimulated using the antigen DNP-BSA. Quasi-static I-V measurements reflected a slow shift in surface potential () which was dependent on extracellular calcium ([Ca]o) and buffer strength, which suggests sensitivity to protons released during exocytosis. Fluorescent imaging of dextran-labeled vesicle release showed evidence of a similar time course, while un-sensitized cells showed no response to stimulation. Transient recordings revealed fluctuations with a rapid rise and slow decay. Chromaffin cells stimulated with high KCl showed both slow shifts and extracellular action potentials exhibiting biphasic and inverted capacitive waveforms, indicative of varying ion-channel distributions across the cell-transistor junction. Our approach presents a facile method to simultaneously monitor exocytosis and ion channel activity with high temporal sensitivity without the need for redox chemistry.
authors.affiliation: Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Krishna
authors.initials: K
authors.lastname: Jayant
authors.affiliation: Department of Chemistry, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Amit
authors.initials: A
authors.lastname: Singhai
authors.affiliation: Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Yingqiu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Joshua B
authors.initials: JB
authors.lastname: Phelps
authors.affiliation: Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Manfred
authors.initials: M
authors.lastname: Lindau
authors.affiliation: Department of Chemistry, Cornell University, Ithaca, NY 14853, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Holowka
authors.affiliation: Department of Chemistry, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Baird
authors.affiliation: Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Kan
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D019439:Chromaffin Cells / Q000737:chemistry*; D004140:Dinitrophenols / Q000737:chemistry; D055664:Electrochemical Techniques; D005089:Exocytosis; D007073:Immunoglobulin E / Q000737:chemistry; D008407:Mast Cells / Q000737:chemistry*; D051381:Rats; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014173:Transistors, Electronic
chemical_list: D004140:Dinitrophenols; C034638:dinitrophenyl-bovine serum albumin; D012710:Serum Albumin, Bovine; D007073:Immunoglobulin E