Microfluidics and Nanofluidics

, Volume 3, Issue 1, pp 1–11 | Cite as

Evaluation of micromilled metal mold masters for the replication of microchip electrophoresis devices

  • Mateusz L. Hupert
  • W. Jason Guy
  • Shawn D. Llopis
  • Hamed Shadpour
  • Sudheer Rani
  • Dimitris E. Nikitopoulos
  • Steven A. Soper
Research Paper

Abstract

High-precision micromilling was assessed as a tool for the rapid fabrication of mold masters for replicating microchip devices in thermoplastics. As an example, microchip electrophoresis devices were hot embossed in poly(methylmethacrylate) (PMMA) from brass masters fabricated via micromilling. Specifically, sidewall roughness and milling topology limitations were investigated. Numerical simulations were performed to determine the effects of additional volumes present on injection plugs (i.e., shape, size, concentration profiles) due to curvature of the corners produced by micromilling. Elongation of the plug was not dramatic (< 20%) for injection crosses with radii of curvatures to channel width ratios less than 0.5. Use of stronger pinching potentials, as compared to sharp-corner injectors, were necessary in order to obtain short sample plugs. The sidewalls of the polymer microstructures were characterized by a maximum average roughness of 115 nm and mean peak height of 290 nm. Sidewall roughness had insignificant effects on the bulk EOF as it was statistically the same for PMMA microchannels with different aspect ratios compared to LiGA-prepared devices with a value of ca. 3.7 × 10−4 cm2/(V s). PMMA microchip electrophoresis devices were used for the separation of pUC19 Sau3AI double-stranded DNA. The plate numbers achieved in the micromilled-based chips exceeded 1 million/m and were comparable to the plate numbers obtained for the LiGA-prepared devices of similar geometry.

Keywords

Micromilling Hot-embossing Microchip electrophoresis Polymer microfluidics 

References

  1. Anderson RC, Su X, Bogdan GJ, Fenton J (2000) A miniature integrated device for automated multistep genetic assays. Nucleic Acid Res 28(12):E60CrossRefGoogle Scholar
  2. Becker H, Gartner C (2000) Polymer microfabrication methods for microfluidic analytical applications. Electrophoresis 21(1):12–26CrossRefGoogle Scholar
  3. Becker H, Locascio LE (2002) Polymer microfluidic devices. Talanta 56(2):267–287CrossRefGoogle Scholar
  4. Bianchi F, Chevolot Y, Mathieu HJ, Girault HH (2001) Photomodification of polymer microchannels induced by static and dynamic excimer ablation: effect on the electroosmotic flow. Anal Chem 73(16):3845–3853CrossRefGoogle Scholar
  5. Blom MT, Hasselbrink EF, Wensink H, Van Den Berg A (2001) Solute dispersion by electroosmotic flow in nonuniform microfluidic channels. Micro Total Analysis Systems 2001. In: Proceedings mTAS 2001 Symposium, 5th, Monterey, CA, United States, Oct 21–25, 2001, pp 615–616Google Scholar
  6. Boone TD, Fan ZH, Hooper HH, Ricco AJ, Tan H, Williams SJ (2002) Plastic advances microfluidic devices. Anal Chem 74(3):78A–86AGoogle Scholar
  7. Chen Z, Gao Y, Lin J, Su R, Xie Y (2004) Vacuum-assisted thermal bonding of plastic capillary electrophoresis microchip imprinted with stainless steel template. J Chromatogr A 1038 (1–2):239–245CrossRefGoogle Scholar
  8. Chen J, Wabuyele M, Chen H, Patterson D, Hupert M, Shadpour H, Nikitopoulos D, Soper SA (2005) Electrokinetically synchronized polymerase chain reaction microchip fabricated in polycarbonate. Anal Chem 77(2):658–666CrossRefGoogle Scholar
  9. Chou SY, Krauss PR, Renstrom PJ (1996) Nanoimprint lithography. J Vac Sci Technol B Microelectron Nanometer Struct 14(6):4129–4133CrossRefGoogle Scholar
  10. Duffy DC, McDonald JC, Schueller OJA, Whitesides GM (1998) Rapid prototyping of microfluidic systems in poly(dimethylsiloxane). Anal Chem 70(23):4974–4984CrossRefGoogle Scholar
  11. Effenhauser CS, Manz A, Widmer HM (1993) Glass chips for high-speed capillary electrophoresis separations with submicrometer plate heights. Anal Chem 65(19):2637–2642CrossRefGoogle Scholar
  12. Effenhauser CS, Paulus A, Manz A, Widmer HM (1994) High-speed separation of antisense oligonucleotides on a micromachined capillary electrophoresis device. Anal Chem 66(18):2949–2953CrossRefGoogle Scholar
  13. Ehrfeld W, Lehr H, Michel F, Wolf A, Gruber H-P, Bertholds A (1996) Micro electro discharge machining as a technology in micromachining. In: Proceedings of SPIE—the international society for optical engineering 2879 (Micromachining and Microfabrication Process Technology II), pp 332–337Google Scholar
  14. Ermakov SV, Jacobson SC, Ramsey JM (2000) Computer simulations of electrokinetic injection techniques in microfluidic devices. Anal Chem 72(15):3512–3517CrossRefGoogle Scholar
  15. Esch MB, Kapur S, Irizarry G, Genova V (2003) Influence of master fabrication techniques on the characteristics of embossed microfluidic channels. Lab Chip 3(2):121–127CrossRefGoogle Scholar
  16. Foley JP, Dorsey JG (1983) Equations for calculation of chromatographic figures of merit for ideal and skewed peaks. Anal Chem 55:730–737CrossRefGoogle Scholar
  17. Friedrich CR, Coane PJ, Goettert J, Gopinathin N (1998) Direct fabrication of deep x-ray lithography masks by micromechanical milling. Precis Eng 22:164–173CrossRefGoogle Scholar
  18. Fu LM, Yang RJ, Lee GB, Liu HH (2002) Electrokinetic injection techniques in microfluidic chips. Anal Chem 74(19):5084–5091CrossRefGoogle Scholar
  19. Fu L-M, Yang R-J, Lee G-B (2003) Electrokinetic focusing injection methods on microfluidic devices. Anal Chem 75(8):1905–1910CrossRefGoogle Scholar
  20. Gerlach A, Knebel G, Guber AE, Heckele M, Herrmann D, Muslija A, Schaller T (2002) Microfabrication of single-use plastic microfluidic devices for high-throughput screening and DNA analysis. Microsyst Technol 7:265–268CrossRefGoogle Scholar
  21. Guber AE, Heckele M, Herrmann D, Muslija A, Saile V, Eichhorn L, Gietzelt T, Hoffmann W, Hauser PC, Tanyanyiwa J, Gerlach A, Gottschlich N, Knebel G (2004) Microfluidic lab-on-a-chip systems based on polymers—fabrication and application. Chem Eng J 101(1–3):447–453CrossRefGoogle Scholar
  22. Harrison DJ, Fluri K, Seiler K, Fan Z, Effenhauser CS, Manz A (1993) Micromachining a miniaturized capillary electrophoresis-based chemical analysis system on a chip. Science 261(5123):895–897CrossRefGoogle Scholar
  23. Huang X, Gordon MJ, Zare RN (1988) Current-monitoring method for measuring the electroosmotic flow rate in capillary zone electrophoresis. Anal Chem 60(17):1837–1838CrossRefGoogle Scholar
  24. Jacobson SC, Hergenroder R, Koutny LB, Warmack RJ, Ramsey JM (1994) Effects of Injection schemes and column geometry on the performance of microchip electrophoresis devices. Anal Chem 66(7):1107–1113CrossRefGoogle Scholar
  25. Jacobson SC, Culbertson CT, Daler JE, Ramsey JM (1998) Microchip structures for submillisecond electrophoresis. Anal Chem 70(16):3476–3480CrossRefGoogle Scholar
  26. Lee GB, Chen SH, Huang GR, Sung WC, Lin YH (2001) Microfabricated plastic chips by hot embossing methods and their applications for DNA separation and detection. Sens Actuators B Chem B75(1–2):142–148CrossRefGoogle Scholar
  27. Liu Y, Foote RS, Jacobson SC, Ramsey RS, Ramsey JM (2000) Electrophoretic separation of proteins on a microchip with noncovalent, postcolumn labeling. Anal Chem 72(19):4608–4613CrossRefGoogle Scholar
  28. Liu Y, Rauch CB, Stevens RL, Lenigk R, Yang J, Rhine DB, Grodzinski P (2002) DNA amplification and hybridization assays in integrated plastic monolithic devices. Anal Chem 74(13):3063–3070CrossRefGoogle Scholar
  29. Liu RH, Yang J, Lenigk R, Bonanno J, Grodzinski P (2004) Self-contained, fully integrated biochip for sample preparation, polymerase chain reaction amplification, and DNA microarray detection. Anal Chem 76(7):1824–1831CrossRefGoogle Scholar
  30. Madou M, Lee LJ, Koelling KW, Daunert S, Lai S, Koh CG, Juang Y, Yu L, Lu Y (2001) Design and fabrication of polymer microfluidic platforms for biomedical applications. ANTEC-SPE 59, pp 2534–2538Google Scholar
  31. Martynova L, Locascio LE, Gaitan M, Kramer GW, Christensen RG, MacCrehan WA (1997) Fabrication of plastic microfluid channels by imprinting methods. Anal Chem 69(23):4783–4789CrossRefGoogle Scholar
  32. Mecomber JS, Stalcup AM, Hurd D, Halsall HB, Heineman WR, Seliskar CJ, Wehmeyer KR, Limbach PA (2006) Analytical performance of polymer-based microfluidic devices fabricated by computer numerical controlled machining. Anal Chem 78:936–941CrossRefGoogle Scholar
  33. Ocvirk G, Munroe M, Tang T, Oleschuk R, Westra K, Harrison DJ (2000) Electrokinetic control of fluid flow in native poly(dimethylsiloxane) capillary electrophoresis devices. Electrophoresis 21(1):107–115CrossRefGoogle Scholar
  34. Pu Q-S, Luttge R, Gardeniers HJGE, Van den Berg A (2003) Comparison of capillary zone electrophoresis performance of powder-blasted and hydrogen fluoride-etched microchannels in glass. Electrophoresis 24(1–2):162–171CrossRefGoogle Scholar
  35. Qi S, Liu X, Ford S, Barrows J, Thomas G, Kelly K, McCandless A, Lian K, Goettert J, Soper SA (2002) Microfluidic devices fabricated in poly(methyl methacrylate) using hot-embossing with integrated sampling capillary and fiber optics for fluorescence detection. Lab Chip 2(2):88–95CrossRefGoogle Scholar
  36. Schaller T, Bohn L, Mayer J, Schubert K (1999) Microstructure grooves with a width of less than 50 um cut with ground hard metal micro end mills. Precis Eng 23:229–235CrossRefGoogle Scholar
  37. Situma C, Wang Y, Hupert M, Barany F, McCarley RL, Soper SA (2005) Fabrication of DNA microarrays onto poly(methyl methacrylate) with ultraviolet patterning and microfluidics for the detection of low-abundant point mutations. Anal Biochem 340(1):123–135CrossRefGoogle Scholar
  38. Slater GW, Mayer P (1995) Electrophoretic resolution versus fluctuations of the lateral dimensions of a capillary. Electrophoresis 16(5):771–779CrossRefGoogle Scholar
  39. Soper SA, Ford SM, Qi S, McCarley RL, Kelly K, Murphy MC (2000) Polymeric microelectromechanical systems. Anal Chem 72(19):643A–651ACrossRefGoogle Scholar
  40. Takacs M, Vero B, Meszaros I (2003) Micromilling of metallic materials. J Mater Process Technol 138:152–155CrossRefGoogle Scholar
  41. Thomas CD, Jacobson SC, Ramsey JM (2004a) Strategy for repetitive pinched injections on a microfluidic device. Anal Chem 76(20):6053–6057CrossRefGoogle Scholar
  42. Thomas G, Sinville R, Sutton S, Farquar H, Hammer RP, Soper SA, Cheng Y-W, Barany F (2004b) Capillary and microelectrophoretic separations of ligase detection reaction products produced from low-abundant point mutations in genomic DNA. Electrophoresis 25(10–11):1668–1677CrossRefGoogle Scholar
  43. Vilkner T, Janasek D, Manz A (2004) Micro total analysis systems. recent developments. Anal Chem 76(12):3373–3386CrossRefGoogle Scholar
  44. Wallenborg SR, Bailey CG (2000) Separation and detection of explosives on a microchip using micellar electrokinetic chromatography and indirect laser-induced fluorescence. Anal Chem 72(8):1872–1878CrossRefGoogle Scholar
  45. Xu J, Locascio L, Gaitan M, Lee CS (2000) Room-temperature imprinting method for plastic microchannel fabrication. Anal Chem 72(8):1930–1933CrossRefGoogle Scholar
  46. Zhang C-X, Manz A (2001) Narrow sample channel injectors for capillary electrophoresis on microchips. Anal Chem 73(11):2656–2662CrossRefGoogle Scholar
  47. Zhao DS, Roy B, McCormick MT, Kuhr WG, Brazill SA (2003) Rapid fabrication of a poly(dimethylsiloxane) microfluidic capillary gel electrophoresis system utilizing high precision machining. Lab Chip 3(2):93–99CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Mateusz L. Hupert
    • 1
  • W. Jason Guy
    • 1
  • Shawn D. Llopis
    • 1
    • 2
  • Hamed Shadpour
    • 1
    • 2
  • Sudheer Rani
    • 1
    • 3
  • Dimitris E. Nikitopoulos
    • 1
    • 3
  • Steven A. Soper
    • 1
    • 2
    • 3
  1. 1.Center for Bio-Modular Multi-Scale SystemsLouisiana State UniversityBaton RougeUSA
  2. 2.Department of ChemistryLouisiana State UniversityBaton RougeUSA
  3. 3.Department of Mechanical EngineeringLouisiana State UniversityBaton RougeUSA

Personalised recommendations