title: Dynamic protein adsorption in microchannels by "stop-flow" and continuous flow.
abstract: This work addresses two ways of loading proteins on microchannel surfaces for immunoassay applications: the "stop-flow" and the continuous flow processes. The "stop-flow" method consists of successive static incubation periods where the bulk solution depletes upon the adsorption process. In the present paper, a multi-step "stop-flow" protein coating is studied and compared to a coating under continuous flow conditions. For the "stop-flow", a non-dimensional parameter is here introduced, indicating the adsorbing capacity of the system, by which it is possible to calculate the number of loads necessary to reach the optimum coverage. For the continuous flow, the effects on the adsorption of the kinetic rates, flow velocity and wall capacity have been considered. This study shows the importance of a careful choice of the fluid velocity to minimise the sample waste. For diffusion controlled and kinetics controlled processes, two flow velocity criteria are provided in order to obtain the best possible coverage, with the same amount of sample as with the "stop-flow".
authors.affiliation: Laboratoire d'Electrochimie Physique et Analytique, Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lionello
authors.forename: Jacques
authors.initials: J
authors.lastname: Josserand
authors.forename: Henrik
authors.initials: H
authors.lastname: Jensen
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004058:Diffusion; D004563:Electrochemistry; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D007700:Kinetics; D007834:Lasers; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D044085:Microfluidics; D015233:Models, Statistical; D009995:Osmosis; D011093:Polyethylene Terephthalates / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D007074:Immunoglobulin G; D011093:Polyethylene Terephthalates; D011506:Proteins