Physiochemical properties of various polymer substrates and their effects on microchip electrophoresis performance.

A suite of polymers were evaluated for their suitability as viable substrate materials for microchip electrophoresis applications, which were fabricated via replication technology. The relevant physiochemical properties investigated included the glass transition temperature (T(g)), UV-vis absorption properties, autofluorescence levels, electroosmotic flow (EOF) and hydrophobicity/hydrophilicity as determined by sessile water contact angle measurements. These physiochemical properties were used as a guide to select the proper substrate material for the intended microchip electrophoretic application. The T(g) of these polymers provided a guide for optimizing embossing parameters to minimize replication errors (REs), which were evaluated from surface profilometer traces. RE values ranged from 0.4 to 13.6% for the polymers polycarbonate (PC) and low-density polyethylene (LDPE), respectively. The absorption spectra and autofluorescence levels of the polymers were also measured at several different wavelengths. In terms of optical clarity (low absorption losses and small autofluorescence levels), poly(methyl methacrylate), PMMA (clear acrylic), provided ideal characteristics with autofluorescence levels comparable to glass at excitation wavelengths that ranged from 488-780 nm. Contact angle measurements showed a maximum (i.e., high degree of hydrophobicity) for polypropylene (PP), with an average contact angle of 104 degrees +/-3 degrees and a minimum exhibited by gray acrylic, G-PMMA, with an average contact angle of 27 degrees +/-2 degrees. The EOF was also measured for thermally assembled chips both before and after treatment with bovine serum albumin (BSA). The electrophoretic separation of a mixture of dye-labeled proteins including; carbonic anhydrase, phosphorylase B, beta-galactosidase, and myosin, was performed on four different polymer microchips using laser-induced fluorescence (LIF) excitation at 632.8 nm. A maximum average resolution of 5.04 for several peak pairs was found with an efficiency of 6.68 x 10(4) plates for myosin obtained using a BSA-treated PETG microchip.

[1]  N. Demarquette,et al.  Evaluation of surface energy of solid polymers using different models , 2000 .

[2]  A. Manz,et al.  Micro total analysis systems. Recent developments. , 2004, Analytical chemistry.

[3]  B. Bidlingmeyer,et al.  Column efficiency measurement , 1984 .

[4]  Agustín Costa-García,et al.  Detection of human immunoglobulin in microchip and conventional capillary electrophoresis with contactless conductivity measurements. , 2004, Analytical chemistry.

[5]  J. Thompson,et al.  Fast analytical-scale separations by capillary electrophoresis and liquid chromatography. , 1999, Chemical reviews.

[6]  H. Elias.  An introduction to plastics , 1993 .

[7]  A D Stroock,et al.  An integrated fluorescence detection system in poly(dimethylsiloxane) for microfluidic applications. , 2001, Analytical chemistry.

[8]  Loïc Dayon,et al.  Microfluidic systems in proteomics , 2003, Electrophoresis.

[9]  Zhanling Wang,et al.  Attomole sensitivity for unlabeled proteins and polypeptides with on‐chip capillary electrophoresis and universal detection by interferometric backscatter , 2003, Electrophoresis.

[10]  Timothy J. Johnson,et al.  Chemical mapping of hot-embossed and UV-laser-ablated microchannels in poly(methyl methacrylate) using carboxylate specific fluorescent probes , 2001 .

[11]  Yan Li,et al.  Integration of isoelectric focusing with parallel sodium dodecyl sulfate gel electrophoresis for multidimensional protein separations in a plastic microfludic network , 2004 .

[12]  W. Stryjewski,et al.  Single molecule detection of double‐stranded DNA in poly(methylmethacrylate) and polycarbonate microfluidic devices , 2001, Electrophoresis.

[13]  Amy E Herr,et al.  On-chip coupling of isoelectric focusing and free solution electrophoresis for multidimensional separations. , 2003, Analytical chemistry.

[14]  Yoshinobu Baba,et al.  A 15-s protein separation employing hydrodynamic force on a microchip. , 2003 .

[15]  M. Strege,et al.  Micellar electrokinetic chromatography of proteins , 1997 .

[16]  Frédéric Reymond,et al.  Polymer microchips bonded by O2‐plasma activation , 2002, Electrophoresis.

[17]  A. Paulus,et al.  Use of peltier thermoelectric devices to control column temperature in high-performance capillary electrophoresis , 1989 .

[18]  E. Hasselbrink,et al.  Zeta potential of microfluidic substrates: 1. Theory, experimental techniques, and effects on separations , 2004, Electrophoresis.

[19]  Jongyoon Han,et al.  Two-dimensional protein separation with advanced sample and buffer isolation using microfluidic valves. , 2004, Analytical chemistry.

[20]  Steven A Soper,et al.  Resist-free patterning of surface architectures in polymer-based microanalytical devices. , 2005, Journal of the American Chemical Society.

[21]  Shawn D. Llopis,et al.  Contact conductivity detection in poly(methyl methacrylate)-based microfluidic devices for analysis of mono- and polyanionic molecules. , 2002, Analytical chemistry.

[22]  Adam T Woolley,et al.  Surface-modified poly(methyl methacrylate) capillary electrophoresis microchips for protein and peptide analysis. , 2004, Analytical chemistry.

[23]  R A Mathies,et al.  Optimization of high-speed DNA sequencing on microfabricated capillary electrophoresis channels. , 1999, Analytical chemistry.

[24]  G. Bruin,et al.  Recent developments in electrokinetically driven analysis on microfabricated devices , 2000, Electrophoresis.

[25]  B. Karger,et al.  High Performance Capillary Electrophoresis , 1988, Nature.

[26]  M. Strege,et al.  Micellar electrokinetic capillary chromatography of proteins. , 1993, Analytical biochemistry.

[27]  Nickolaj J. Petersen,et al.  Effect of Joule heating on efficiency and performance for microchip‐based and capillary‐based electrophoretic separation systems: A closer look , 2004, Electrophoresis.

[28]  V. Dolnik,et al.  Wall coating for capillary electrophoresis on microchips , 2004, Electrophoresis.

[29]  A. Rathore,et al.  Theory of electroosmotic flow, retention and separation efficiency in capillary electrochromatography , 2002, Electrophoresis.

[30]  J. Rossier,et al.  Microchannel networks for electrophoretic separations , 1999, Electrophoresis.

[31]  Yolanda Y. Davidson,et al.  Surface modification of poly(methyl methacrylate) used in the fabrication of microanalytical devices. , 2000, Analytical chemistry.

[32]  Thermoreversible Gelation of Isotropic and Liquid Crystalline Solutions of a “Sticky” Rodlike Polymer , 2000 .

[33]  J. Rossier,et al.  UV Laser Machined Polymer Substrates for the Development of Microdiagnostic Systems. , 1997, Analytical chemistry.

[34]  Lin Chen,et al.  (Review Article) High-Throughput DNA Analysis by Microchip Electrophoresis , 2004 .

[35]  Xu,et al.  Room-temperature imprinting method for plastic microchannel fabrication , 2000, Analytical chemistry.

[36]  E. Wang,et al.  Capillary electrophoresis coupling with electrochemiluminescence detection: a review , 2005 .

[37]  J. Pawliszyn,et al.  Microfabrication of a tapered channel for isoelectric focusing with thermally generated pH gradient , 2002, Electrophoresis.

[38]  N. Dovichi,et al.  Capillary electrophoresis for the analysis of biopolymers. , 2000, Analytical chemistry.

[39]  Zhifang Fan,et al.  Miniaturized capillary isoelectric focusing in plastic microfluidic devices , 2002, Electrophoresis.

[40]  Yuehe Lin,et al.  Microfabricated isoelectric focusing device for direct electrospray ionization‐mass spectrometry , 2000, Electrophoresis.

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

[42]  G. Whitesides,et al.  Self-Assembled Monolayers That Resist the Adsorption of Proteins and the Adhesion of Bacterial and Mammalian Cells , 2001 .

[43]  Z. Demianová,et al.  Zone electrophoresis of proteins on a poly(methyl methacrylate) chip with conductivity detection. , 2003, Journal of chromatography. A.

[44]  B. Logan,et al.  Residence time, loading force, pH, and ionic strength affect adhesion forces between colloids and biopolymer-coated surfaces. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[45]  Annelise E Barron,et al.  Microchannel wall coatings for protein separations by capillary and chip electrophoresis , 2003, Electrophoresis.

[46]  M. Nicholas,et al.  Some effects of substrate roughness on wettability , 1981 .

[47]  H. Sugimura,et al.  Ultra-Water-Repellent Poly(ethylene terephthalate) Substrates , 2003 .

[48]  Ford,et al.  Polymeric microelectromechanical systems , 2000, Analytical chemistry.

[49]  R A Mathies,et al.  Turn geometry for minimizing band broadening in microfabricated capillary electrophoresis channels. , 2000, Analytical chemistry.

[50]  M. Edrissi,et al.  Preparation and characterization of CoxMnmCrnNikFe3-(x+m+n+k)O4 ferrites and optimization of their structural and magnetic properties by Taguchi experimental design , 2002 .

[51]  C Gärtner,et al.  Polymer microfabrication methods for microfluidic analytical applications , 2000, Electrophoresis.

[52]  M. Wirth,et al.  Surface modification of the channels of poly(dimethylsiloxane) microfluidic chips with polyacrylamide for fast electrophoretic separations of proteins. , 2004, Analytical chemistry.

[53]  Detlev Belder,et al.  Surface modification in microchip electrophoresis , 2003, Electrophoresis.

[54]  R. Zare,et al.  Current-monitoring method for measuring the electroosmotic flow rate in capillary zone electrophoresis , 1988 .

[55]  Prashanta Dutta,et al.  Isoelectric focusing in a poly(dimethylsiloxane) microfluidic chip. , 2005, Analytical chemistry.

[56]  E. Hasselbrink,et al.  Zeta potential of microfluidic substrates: 2. Data for polymers , 2004, Electrophoresis.

[57]  Yan Li,et al.  Dynamic analyte introduction and focusing in plastic microfluidic devices for proteomic analysis , 2003, Electrophoresis.