Microchip Dialysis of Proteins Using in Situ Photopatterned Nanoporous Polymer Membranes

Abstract

Chip-level integration of microdialysis membranes is described using a novel method for in situ photopatterning of porous polymer features. Rapid and inexpensive fabrication of nanoporous microdialysis membranes in microchips is achieved using a phase separation polymerization technique with a shaped UV laser beam. By controlling the phase separation process, the molecular weight cutoffs of the membranes can be engineered for different applications. Counterflow dialysis is used to demonstrate extraction of low molecular weight analytes from a sample stream, using two different molecular weight cutoff (MWCO) membranes; the first one with MWCO below 5700 for desalting protein samples, and the second one with a higher MWCO for size-based fractionation of proteins. Modeling based on a simple control volume analysis on the microdialysis system is consistent with measured concentration profiles, indicating both that membrane properties are uniform, well-defined, and reproducible and that diffusion of subcutoff analytes through the membrane is rapid.

Microfluidic patterning of alginate hydrogels

“…2,8 Thermoresponsive hydrogels are used for pumping, metering, and flow regulation in microfluidic chips. 9,10 Other microfluidic systems utilize porosity and high flow resistance of the gels for analytical applications such as dialysis, 11 electrophoresis, 12-15 substance enrichment, 16,17 and sample separation by a combination of electrokinetic and hydrodynamic flows. 18 Hydrogels are also used as encapsulation matrices for microfluidic enzyme bioreactors and sensors.…”

Flow characterization of electroconvective micromixer with a nanoporous polymer membrane in-situ fabricated using a laser polymerization technique

“…The fabrication process of the membrane is the same as that employed by Song et al 19 In the present study, the membrane with a low molecular weight cut-off (MWCO) was used, for which the pore size was reported to be smaller than that of FITC-insulin (5700 Da). Briefly, the U-shape microchannel was coated with a 2:2:1 (vol) mixture of deionized water, glacial acetic acid (DAEJUNG), and 3-trimethoxysilylpropyl acrylate (Sigma-Aldrich) so that the channel surface could be covalently bonded with the nanoporous membrane.…”

“…3(a) to fabricate the nanoporous polymer membrane using a phase separation method. 19,20 A monomer solution was prepared using 2-(N-3-sulfopropyl-N, N-dimethylammonium)ethyl methacrylate (SPE, RASCHIG) as a monomer, N,N 0 -methylenebisacrylamide (BIS, Sigma-Aldrich) as a crosslinker, 2,2 0 azobis(2-methylpropanimidamide)-dihydrochloride (v50, Sigma-Aldrich) as a photoinitiator, and a solvent mixture of DI water and 2-methoxyethanol (Sigma-Aldrich). The laser beam with a wavelength of 355 nm (FTSS355-Q048, CryLaS) was shaped to a laser sheet using a slit and lenses.…”

Separation by Molecular Weight during Purification Process of Lignophenol

“…Moreover it is worthy to separate components by molecular size for various advanced applications. But in general, molecular weight separations are carried out by gel-permeation separation, membrane separation or ultra-filteration membrane mainly in bio-chemical, proteins DNA chemistry, medical [4][5] and waste water treatment [6]. Although these methods can cut-off molecular weights exactly, it is hard to treat large amount of materials.…”