title: A microfluidic paper-based device to assess acetylcholinesterase activity.
abstract: Neurotransmitters play key roles in cell-to-cell communication. These chemical messengers are involved in many functional processes, including growth, reproduction, memory, and behavior. In this communication, we describe a novel microfluidic paper-based analytical device (μPAD) to detect acetylcholinesterase (AChE) activity and inhibitor screening through a colorimetric analysis. The μPAD is easily fabricated via a wax printing process whereby wax is deposited onto the surface of chromatographic paper, and heated to create a hydrophobic barrier. Separate solutions of 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) and samples containing AChE and acetylthiocholine iodide (ATC) (or cysteine, Cys), respectively, are directly spotted onto the μPAD. DTNB and AChE/ATC (or Cys) flow towards each other where a reaction occurs to form the yellow colored 2-nitro-5-thiobenzoic acid anion (TNB2-). The device is dried, scanned, and analyzed yielding a linear range of average inverse yellow intensities versus substrate concentration. An IC50value (0.045 nM) with a known inhibitor, neostigmine bromide (NB), is obtained on the device. μPADs are low cost and easy to fabricate and have great potential to quantify neurotransmitter activity.
authors.affiliation: Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA.|School of Pharmacy, Xi'an Medical University, Xi'an, P. R. China.
authors.forename: Chunye
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Gomez
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D003124:Colorimetry; D004136:Dinitrobenzenes / Q000032:analysis / Q000378:metabolism; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D009388:Neostigmine / Q000494:pharmacology; D010209:Paper
chemical_list: D002800:Cholinesterase Inhibitors; D004136:Dinitrobenzenes; D009388:Neostigmine; D000110:Acetylcholinesterase; C010936:2,4-dinitrothiocyanatobenzene
keywords: Acetylcholinesterase; Assay; Paper microfluidics