Protein adsorption in static microsystems: effect of the surface to volume ratio
A numerical model for the adsorption kinetics of proteins on the walls of a microchannel has been developed using the finite element method (FEM) to address the coupling with diffusion phenomena in the restricted microchannel volume. Time evolutions of the concentration of one species are given, both in solution and on the microchannel walls. The model illustrates the adsorption limitation sometimes observed when the microdimensions of these systems induce a global depletion of the bulk solution. A new non-dimensional parameter is introduced to predict the final value of the coverage of any microsystem under static adsorption. A working curve and a criteria (h/KΓmax > 10) are provided in order to choose, for given adsorption characteristics, the value of the volume-to-surface ratio (i.e. the channel height h) avoiding depletion effects on the coverage (relative coverage greater than 90% of the theoretical one). Simulations were compared with confocal microscopy measurements of IgG antibody adsorption on the walls of a PET microchannel. The fit of the model to the experimental data show that the adsorption is under apparent kinetic control.
Labchip_5_2005_254.pdf
Publisher's version
openaccess
509.95 KB
Adobe PDF
0cbc82f08efa198cf7ea956947e4c6cf
b411179f_SI.doc
openaccess
134 KB
Microsoft Word
23df3dbb4430ee34327bd28e39e6c9e8