Protein Separation with Self-Assembled Nanoparticle Beds: Mechanism and Separation Performance

• Author / Creator

  Azim, Mohammad Alaul

• This thesis reports the separation behavior of SDS-protein complexes in colloidal self-assembled (CSA) nanoparticle beds, and the processes of stabilization of CSA beds for high voltage separation. First, the variation of electrophoretic mobility with molecular weight (6.5-66 kDa) of SDS-protein complexes and with particle size (150-690 nm) was evaluated using a classical, modified Ogston sieving model for protein separation for a random pore gel structure, and using the modified Giddings analysis developed by Wirth for uniform pores structure. The results show improved fits (R2 = 0.993-0.997) and better predictive interpolations of the molecular weight on unknowns using the Wirth/Giddings model for a uniform pore structure. The quality of fit of the single pore size model indicates that it is meaningful to characterize these structures as having a predominantly single pore size. A CSA bed of native silica nanoparticles is not stable for high voltage application. Two different approaches have been demonstrated to stabilize the CSA beds in this work. By reducing the depth of the CSA beds by half or more, three to four times the electric field stability (from ≤ 320 V/cm for 20 µm thick bed to ̴ 2250 V/cm for 4 µm thick bed) is achieved. Narrowing the capillary bore greatly stabilized the particle beds, even for smaller particle assemblies. The improved separation performance of narrow bore capillaries increases the particle bed performance in protein separation. But unfortunately the narrow bore chips are still not stable for long term repetitive use. These kind of chips are suitable for up to 5-6 runs at highest stable voltage. Base catalyzed sol-gel polymerization introduces cross links between the particles to entrap them, and solves the problem. But the acid catalyzed gel filled the pores and made the microchip unusable. The CSA bed entrapped by gel can be used for at least a week (10-15 runs /day) and the reproducibility of fabrication is high (yield = 90%). This study demonstrates that gel entrapped particles bed can be used for high performance SDS-protein separation up to several days without significant deviation of chip performance. The results demonstrate that this simple and inexpensive fabrication process for microchips with a CSA bed has high potential in improving protein analysis, compared to competing technologies such as conventional gels.

• Subjects / Keywords

  • Colloidal Self Assembly (CSA)
  • Nanoparticles
  • Microfluidics
  • Protein separation
  • Microchip

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3V698V0M

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.