A PDMS viscometer for assaying endoglucanase activity.

A poly(dimethylsiloxane) (PDMS) viscometer was developed to analyze the activity of endo-β-1,4-glucanases (EC3.2.1.4) on hydrolyzing sodium carboxymethylcellulose (NaCMC). In the viscometer, a PDMS pump was used as the vacuum source to drive the fluid flow in the PDMS microchannel. The numerical simulation by COMSOL suggested that the vacuum level of the PDMS pump increased during the viscosity measurement. The increasing vacuum level of the PDMS pump allowed more stable fluid flow than the constant vacuum of the conventional vacuum pump. By monitoring the fluids traveling in the microchannel, the viscosity of the endoglucanase-NaCMC solution was derived at different reaction times. The non-Newtonian behavior of the NaCMC solution was studied to ensure that the viscosity measurement was performed in the Newtonian range. A protocol was established to convert the viscometric activity to the activity of standard international units with Almin's method. The PDMS viscometer required only 20 μL sample for the endoglucanase assay and the results were in good agreement with the results from Ubbelohde viscometers.

[1]  G. Whitesides,et al.  Rapid Prototyping of Microfluidic Systems in Poly(dimethylsiloxane). , 1998, Analytical chemistry.

[2]  K. Ozaki,et al.  Alkaline Cellulase for Laundry Detergents: Production by Bacillus sp. KSM-635 and Enzymatic Properties , 1989 .

[3]  B. Zheng,et al.  A poly(dimethylsiloxane) viscometer for microliter power law fluids , 2009 .

[4]  G. Whitesides,et al.  Poly(dimethylsiloxane) as a material for fabricating microfluidic devices. , 2002, Accounts of chemical research.

[5]  R. Good,et al.  Thermodynamics of contact angles. I. Heterogeneous solid surfaces , 1972 .

[6]  S. Au,et al.  Nanoliter dispensing method by degassed poly(dimethylsiloxane) microchannels and its application in protein crystallization. , 2007, Analytical chemistry.

[7]  Mark A Burns,et al.  Analysis of non-Newtonian liquids using a microfluidic capillary viscometer. , 2006, Analytical chemistry.

[8]  Michael Somogyi,et al.  NOTES ON SUGAR DETERMINATION , 1926 .

[9]  Reeta Rani Singhania,et al.  Microbial cellulases ─ Production, applications and challenges , 2005 .

[10]  Norton Nelson,et al.  A PHOTOMETRIC ADAPTATION OF THE SOMOGYI METHOD FOR THE DETERMINATION OF GLUCOSE , 1944 .

[11]  M. Hulme.  Viscometric determination of carboxymethylcellulase in standard international units. , 1971, Archives of biochemistry and biophysics.

[12]  Y. Kimura,et al.  Purification and characterization of a protease-resistant cellulase from Aspergillus niger , 1995 .

[13]  J. A. Jorge,et al.  Xylanases from fungi: properties and industrial applications , 2005, Applied Microbiology and Biotechnology.

[14]  K. Eriksson,et al.  Enzymic degradation of polymers. I. Viscometric method for the determination of enzymic activity. , 1967, Biochimica et biophysica acta.

[15]  R. Hoffman.  A study of the advancing interface. I. Interface shape in liquid—gas systems , 1975 .

[16]  T. Aimi,et al.  Enhancement of the viscometric endocellulase activity of Polyporus arcularius CMCase IIIa by cellobiose and cellooligosaccharides , 2005 .

[17]  Xiaoju Tang,et al.  A PDMS viscometer for microliter Newtonian fluid , 2007 .

[18]  G. Whitesides,et al.  Fabrication of microfluidic systems in poly(dimethylsiloxane) , 2000, Electrophoresis.

[19]  Sharon P. Shoemaker,et al.  The use of capillary viscometry, reducing end-group analysis, and size exclusion chromatography combined with multi-angle laser light scattering to characterize endo-1,4-β-d-glucanases on carboxymethylcellulose: a comparative evaluation of the three methods , 1998 .

[20]  Charles-Henri Bruneau,et al.  Viscosimeter on a microfluidic chip. , 2006, Langmuir : the ACS journal of surfaces and colloids.

[21]  J. Aubert,et al.  The biological degradation of cellulose. , 1994, FEMS microbiology reviews.

[22]  K. Eriksson,et al.  Enzymic degradation of polymers. II. Viscometric determination of cellulase activity in absolute terms. , 1967, Biochimica et biophysica acta.

[23]  Bruce K. Gale,et al.  A PDMS-based gas permeation pump for on-chip fluid handling in microfluidic devices , 2006 .

[24]  Kae Sato,et al.  Power-free poly(dimethylsiloxane) microfluidic devices for gold nanoparticle-based DNA analysis. , 2004, Lab on a chip.