(a)–(f) Fluorescence microcopy images of IgG streaming iDEP in an array of triangular posts. The scale bar indicates 20 μm and the flow direction is from top to bottom. Below each image in (a)–(d) is a profile intensity plot at the position marked in (a) (black line). (a)–(d) Streamlines are observed due to positive DEP at an applied electric field of 4200 V/cm with pH buffer media in the range of pH 6.5-8: (a) pH 8, (b) pH 7.5, (c) pH 7, (d) pH 6.5. Positive DEP streaming is decreased from (a) to (d) while decreasing the medium pH results as an decrease of the concentration. (e) and (f) Protein aggregates are formed regardless of the presence of CHAPS at (e) pH 4 and (f) pH 9.
Concentration factor observed experimentally for an applied electric field of 2800 and 4200 V/cm for changes in medium pH ranging from pH 6.5 to 8.
DEP streaming simulation for IgG molecules within a triangular post array at 4200 V/cm. (a)–(c) Streaming concentration at steady-state according to positive DEP with varying μek of (a) 1.5 × 10−8 m2/(Vs), (b) 0.5 × 10−8 m2/(Vs), and (c) 0.1 × 10−8 m2/(Vs) to reflect changes in EOF. (d) Profile plots of (a)–(c) at the midpoint line of the two rows of posts. μek is varied (reflecting changes in EOF) as indicated in the inset while other parameters remain constant with μdep = 8.6 × 10−24 m4/(V2s) and D = 3.89 × 10−11 m2/s.
Profile plots for varying μdep at the midpoint line of the two rows of posts while the other parameters stay constant; μek = 1.5 × 10−8 m2/(Vs) and D = 3.89 × 10−11 m2/s.
(a) Fluorescence microcopy image of streaming iDEP of fluorescently labeled IgG molecules in an array of triangular posts for 3 mM F108. Concentration depletion along the streamlines is observed due to negative DEP at an applied electric field of 4200 V/cm at pH 8. (b) Normalized concentration as obtained from the simulation within a triangular post array at 4200 V/cm in the case of negative DEP (μdep = −1.28 × 10−23 m4/V2s). The scale bar indicates 20 μm and the flow direction is from top to bottom. The color bar indicates concentration in arbitrary units.
Depletion factor observed experimentally for an applied electric field of 1400, 2800, and 4200 V/cm under 3 mM F108 dynamic coating procedure.
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