Presentation on theme: "D. Yu1, S.-Y. Kim1, Y. Cho2, J. Y. Lee2, H. J. Kim2, and J. W. Kim2"— Presentation transcript:
1 Effect of Mass Transport on the Protein Adsorption in a Miniaturized SPR Sensor; SpreetaTM D. Yu1, S.-Y. Kim1, Y. Cho2, J. Y. Lee2,H. J. Kim2, and J. W. Kim21 Department of PhysicsKangwon National University2 Biomedlab Co.Effect of Mass TransportUsing the SPREETATM that is a SPR based sensor, we studied the effect of mass transport on the adsorption of albumin to the gold surface. The mass transport effect dominates the adsorption rate when the binding of albumin onto the gold surface becomes more dominant than the diffusion of albumin near the surface.Expectation effectUnder completely transport-limited conditions initial binding rates can be expected to increase in parallel with the albumin concentration and flow rate1/3.
3 Inner Structure of SpreetaTM 18.5㎜28㎜41㎜Gold Mirror FilmThermistorLEDGold waferDetectorSPREETATM sensor based on the SPR principle
4 Mass Transport(M.T.) Compartment models C ri a Mass transport effects occur when the binding rate of analyte to the ligand is higher than diffusion of analyte to the surface. Flow rate is experimental parameter that can be controlled to minimize mass transport effects.Compartment modelsariCA compartment model for ligands binding to receptors on spherical surface of radius a.The space outside the sphere is divided into an inner region a< r ≤ ri, where the ligand concentration is C and outer region, r > ri, where the ligand concentration equals the bulk concentration C.
5 Calculation of Mass transport coefficient(km) V : denote the volume of innercompartment.A : the surface area of the cell.R : the concentration of freereceptors on the cell surface.C : free ligand concentration inthe inner compartment.B : bound ligand concentrationon the cell surface.C : bulk concentration.At t=0, dC/dt=0 (initial condition)
6 Phosphate Buffered Saline(PBS) Process of ExperimentAlbumin SolutionMeasurement of M.T.Deionized Water(D.W)Calibration sensor0.1M NaOH + 1% Triton X-100Washing sensorD.WPhosphate Buffered Saline(PBS)Set a base linePBSTemperature SensorTeflon TubingBacking PlateTeflon Connector BlockFlow CellGold SPR Surface
7 Experiment ResultRelation between concentration and initial binding rateFixed flow rate(15㎕/min)and variable concentration(5, 25, 50, 100㎍/㎖)The initial binding rate was clearly influenced by changes in the concentration.
8 Experiment ResultResponse Unit data on flow rateRelation between flow rate and initial binding rateFixed concentration(25㎍/㎖) and variable flow rate(5, 15, 25, 125㎕/min)The initial binding rate was clearly influenced by changes in the flow rate.
9 DiscussionThe initial binding rate was found to be proportional to concentration and flow rate1/3, which is in good accordance with theoretical expectations.We also found the reaction was dependent on concentration and flow rate, which provides further support for the mass transport limited model.A benefit of the mass transport is that it may be used to determine the amount concentration of analyte.The investigation of the mass transport effect may help to understand the fluidics.