Modification of a flow cell to measure adsorption kinetics under stagnation point flow and development of a setup correction procedure for obtaining adsorption kinetics at the stagnation point

摘要

This application describes a flow cell to perform experiments under well-controlled hydrodynamic conditions. The resulting cell enables combining the advantages of in-situ spectroscopic ellipsometry with stagnation point flow conditions. An additional advantage is that the proposed cell features a fixed position of the “inlet conduit” with respect to the substrate, thus facilitating the alignment of multiple substrates. Theoretical calculations were performed by computational fluid dynamics and compared with experimental data (adsorption kinetics) obtained for the adsorption of polyethylene glycol to silica under a variety of experimental conditions. Additionally, a simple methodology to correct experimental data for errors associated with the size of the measured spot and for variations of mass transfer in the vicinity of the stagnation point is herein introduced. The proposed correction method would allow researchers to reasonably estimate the adsorption kinetics at the stagnation point and quantitatively compare their results, even when using different experimental setups. The applicability of the proposed correction function was verified by evaluating the kinetics of protein adsorption under different experimental conditions.

主权项

1. A device coupleable to a flow cell comprising:
an inlet conduit comprising an exit port, wherein the inlet conduit is configured to receive a fluid containing an adsorbate during use; a substrate holder configured to couple to a substrate during use; an inlet conduit positioner coupled to the inlet conduit; wherein the exit port is positioned by the inlet conduit positioner such that fluid flows from the exit port toward the substrate during use and impinges the surface of a substrate, positioned in the substrate holder, at a point substantially coincident with light striking the substrate from a light inlet of the flow cell; and wherein the inlet conduit positioner is configured to alter the distance of the exit port from the substrate and/or adjust the angle of the exit port with respect to the surface of the substrate.