pH-controlled diffusion of proteins with different pI values across a nanochannel on a chip.
Electrostatic interactions dominate the diffusion of proteins in a nanochannel, which was measured and modeled for pH values above and below the isoelectric points of three lectin proteins. Maximal diffusion coefficients were obtained when the proteins were neutral at their pI. This pH-controlled transport led to a separation of biomolecules across the nanochannel. A pI shift was observed, due to reversible adsorption of proteins on the walls, which affects the pH in the nanochannel.
Schoch
Reto B
RB
Microsystems Laboratory, STI-LMIS, EPFL, CH-1015 Lausanne, Switzerland. reto.schoch@epfl.ch
Bertsch
Arnaud
A
Renaud
Philippe
P
D004058:Diffusion; D016650:Fluorescein-5-isothiocyanate; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D007526:Isoelectric Point; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism*; D046208:Microchip Analytical Procedures / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods*; D055672:Static Electricity
D037102:Lectins; D016650:Fluorescein-5-isothiocyanate