title: A novel polydimethylsiloxane microfluidic viscometer fabricated using microwire-molding.
abstract: We present a new economical microfluidic viscometer to measure the viscosity of biological fluids, using sample volumes of less than 200 μl. It is fabricated using a microwire-molding technique, making it easier and cheaper to produce than existing viscometers. The viscometer is based on laminar flow inside a polydimethylsiloxane microchip. The velocity of the sample flow inside the capillary was monitored with a camera, and the movement of the liquid column was determined by a Matlab video-processing program. The device was calibrated using deionized water, which is a Newtonian fluid, at 20 °C. The viscometer provides accurate measurements of viscosity for values as small as 0.69 mPa s. The viscosity of water at different temperatures was measured, showing more than 98% agreement with the values provided by the National Institute of Standards and Technology. Various samples including a series of glycerol solutions, phosphate-buffered saline, alcohol, and cell media were also tested, and the measured viscosities were compared with those from a traditional glass capillary viscometer. The results show good agreement between the two methods, with an average relative error of less than 1%. Furthermore, the viscosities of several cell suspensions were measured, showing a relative standard deviation of less than 1.5%. The microchip viscometer is economical and is shown to be accurate, which is very important for the simulation and control of lab-on-a-chip experiments.
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Misha
authors.initials: M
authors.lastname: Zou
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Shaoxi
authors.initials: S
authors.lastname: Cai
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Zhenli
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Longcong
authors.initials: L
authors.lastname: Chen
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Fan
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400044, China.
authors.forename: Sijia
authors.initials: S
authors.lastname: Chen
mesh_terms: D000438:Alcohols; D002138:Calibration; D003470:Culture Media; D004129:Dimethylpolysiloxanes; D005990:Glycerol; D007091:Image Processing, Computer-Assisted / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D011312:Pressure; D012984:Software; D012996:Solutions; D013696:Temperature; D014741:Video Recording / Q000379:methods; D014783:Viscosity; D014867:Water
chemical_list: D000438:Alcohols; D003470:Culture Media; D004129:Dimethylpolysiloxanes; D012996:Solutions; D014867:Water; C013830:baysilon; D005990:Glycerol