Fabrication of a hybrid PDMS/SU-8/quartz microfluidic chip for enhancing UV absorption whole-channel imaging detection sensitivity and application for isoelectric focusing of proteins

Lab on a Chip ◽  
2009 ◽  
Vol 9 (13) ◽  
pp. 1926 ◽  
Author(s):  
Junjie Ou ◽  
Tomasz Glawdel ◽  
Carolyn L. Ren ◽  
Janusz Pawliszyn
Keyword(s):  
Isoelectric Focusing ◽  
Microfluidic Chip ◽  
Uv Absorption ◽  
Detection Sensitivity ◽  
Imaging Detection

Integration of a PDMS/SU-8/Quartz Microfluidic Chip With a Novel Macroporous Poly Dimethylsiloxane (PDMS) Membrane for Isoelectric Focusing of Proteins Using Whole-Channel Imaging Detection

2010 ◽  
Author(s):  
Seyed Mostafa Shameli ◽  
Caglar Elbuken ◽  
Carolyn L. Ren ◽  
Janusz Pawliszyn
Keyword(s):  
Isoelectric Focusing ◽  
Single Point ◽  
Constant Electric Field ◽  
Stray Light ◽  
Detection Sensitivity ◽  
Detection Methods ◽  
Field Samples ◽  
Imaging Detection ◽  
Separation Of Proteins ◽  
Point Detection

Capillary isoelectric focusing (CIEF) is a high-resolution capillary electrophoresis (CE) technique for separating zwitterionic biomolecules, such as proteins and peptides. In this method, by generating a stable pH gradient along the length of the capillary and under the influence of a constant electric field, samples can be separated according to their different isoelectric points (pI). For identifying the focused zones in CIEF, the whole column imaging detection (WCID) is more reliable than any other single point detection methods since it avoids the need of focused peak mobilization, presenting several advantages such as lower detection time, minimized peak dispersion and consequently higher resolution. Capillary-based IEF-WCID has been invented by Convergent Bioscience Inc. (iCE280 analyzer) for separation of proteins and biomarkers [1–2]. In the iCE280 analyzer, hollow fibers are glued to the capillary to separate electrolytes from the samples and a metal slit with a 65 μm opening is glued to the top of the capillary to improve detection sensitivity by blocking stray light. However, this method has several limitations because of the use of capillary such as low throughput, difficulty to be integrated with other separation modes and low detection sensitivity.

Integration of Dialysis Membranes into a Poly(dimethylsiloxane) Microfluidic Chip for Isoelectric Focusing of Proteins Using Whole-Channel Imaging Detection

2008 ◽  
Vol 80 (19) ◽  
pp. 7401-7407 ◽  
Author(s):  
Junjie Ou ◽  
Tomasz Glawdel ◽  
Razim Samy ◽  
Shuwen Wang ◽  
Zhen Liu ◽  
...  
Keyword(s):  
Isoelectric Focusing ◽  
Microfluidic Chip ◽  
Dialysis Membranes ◽  
Imaging Detection

Free Flow Isoelectric Focusing in a Microfluidic Device

2014 ◽  
Author(s):  
Kisoo Yoo ◽  
Prashanta Dutta ◽  
Jin Liu
Keyword(s):  
Mathematical Model ◽  
Isoelectric Focusing ◽  
Microfluidic Device ◽  
Microfluidic Chip ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Free Flow ◽  
Charged Species ◽  
Simulation Results ◽  
Separation Of Proteins

In recent years, there are growing interests in the use of free flow isoelectric focusing (FFIEF). In FFIEF, a thin sheath of laminar flow is introduced perpendicular to the direction of the applied electric field for continuous separation of proteins and charged species. This technique is especially useful in microfluidic device since the electrophoretically separated bands do not have to be mobilized for detection or further analysis. In this study, a mathematical model is developed to simulate free flow isoelectric process in microfluidic devices considering electroneutrality and incompressibility of electrolytes. Our mathematical model is based on mass, momentum and charge conservation equations. A finite volume based numerical scheme is implemented to simulate two dimensional FFIEF in a microfluidic chip. Simulation results indicate that pH gradient forms as samples flow downstream and proteins can be separated effectively using this technique. A new design of microfluidic chip is proposed for separation for cardiac troponin I from serum albumin using FFIEF technique.

Multistage Isoelectric Focusing: A Novel On-Chip Bio-Separation Technique

2005 ◽  
Author(s):  
Prashanta Dutta ◽  
Keisuke Horiuchi ◽  
Huanchun Cui ◽  
Cornelius F. Ivory
Keyword(s):  
Isoelectric Focusing ◽  
Microfluidic Chip ◽  
Soft Lithography ◽  
Fluorescent Protein ◽  
Ph Gradient ◽  
Resolving Power ◽  
Protein Species ◽  
Second Stage ◽  
On Chip ◽  
Bonding Technique

This experimental study reports a method to increase the resolving power of isoelectric focusing (IEF) on a polymeric microfluidic chip. Microfluidic chip is formed on poly-di-methyl siloxane (PDMS) using soft lithography and multilayer bonding technique. In this novel bioseparation technique, IEF is staged by first focusing protein species in a straight channel using broad-range ampholytes and then refocusing segments of that first channel into secondary channels that branch out from the first one. Experiments demonstrated that three fluorescent protein species within a segment of pH gradient in the first stage were refocused in the second stage with much higher resolution in a shallower pH gradient. A serially performed two-stage IEF was completed in less than 25 minutes under particularly small electric field strength up to 100 V/cm.

Fluorescence imaging detection for capillary isoelectric focusing

1995 ◽  
Vol 16 (1) ◽  
pp. 1474-1478 ◽  
Author(s):  
Xing-Zheng Wu ◽  
Jiaqi Wu ◽  
Janusz Pawliszyn
Keyword(s):  
Fluorescence Imaging ◽  
Isoelectric Focusing ◽  
Capillary Isoelectric Focusing ◽  
Imaging Detection
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