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Simulation of a BioMEMS DeviceSimulation of a BioMEMS Device

Can Ozcan & Metin OzenOZEN ENGINEERING, INC.

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OBJECTIVE

• SUCCESSFUL SIMULATION OF A BIOMEMS DEVICE

• COUPLED FLOW & CHEMISTRY• COMPARE DIFFERENT DESIGNS

– CIRCULAR CROSS SECTION– SQUARE CROSS SECTION

• MAKE DESIGN & MANUFACTURING DECISIONS BASED ON SIMULATION RESULTS

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GEOMETRY

• CIRCULAR • SQUARE

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SENSOR SURFACE

• CIRCULAR • SQUARE

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SURFACE CHEMISTRY(SENSOR SURFACE)

• A + L AL

where• A – Free Analyte• L – Free Ligand• AL – Ligand Analyte Complex• ka – Association rate• kd – Dissociation rate

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CFX SET UP

• TRANSIENT• FLUID SPECIFIED AS MIXTURE

– WATER– ANALYTE

• ANALYTE CONSTRAINED BY TRANSPORT EQUATION AND A KINEMATIC DIFFUSION COEFFICIENT

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CFX SET UP

• “AL” SPECIFIED AS ADDITIONAL VARIABLE WITH ZERO DIFFUSIVITY.

• INTIALLY, EVERYTHING SET TO ZERO.

• FIRST LET MIXTURE (WITH ZERO ANALYTE) FLOW THROUGH SYSTEM.

• AFTER A FEW SECONDS, ANALYTE IS ACTIVATED IN MIXTURE WITH A STEP FUNCTION.

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CFX SET UP

• ADDITIONAL VARIABLE “AL” IS SPECIFIED AS “ZERO FLUX” AT ALL WALLS EXCEPT “SENSOR SURFACE”.

• AT THE SENSOR SURFACE, “AL” IS SPECIFIED AS A REACTION SPECIFIED BY THE SOLUTION OF THE CHEMICAL REACTION WITH AN EXPRESSION THAT INVOLVES A SOLUTION VARIABLE – ANALYTE MASS CONCENTRATION

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RESULTS – CHEMICAL REACTION

CIRCULAR

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RESULTS – CHEMICAL REACTION

SQUARE

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RESULTS – TIME HISTORY

• “AL”

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RESULTS – TIME HISTORY

• “AL”

"AL"

0

0.000000002

0.000000004

0.000000006

0.000000008

0.00000001

0.000000012

Time [s] 1.89999 3.89999

CIRCULAR

SQUARE

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CONCLUSIONS

• CFX PROVIDES THE CAPABILITY TO SOLVE COUPLED FLOW & CHEMISTRY– BULK & SURFACE CHEMISTRY

• CFX ENABLES THE USERS TO BRING IN SOLUTION VARIABLES, EXPRESSIONS, LOCATORS, AND BOTH USER & CEL FUNCTIONS FOR COMPLEX MODELING

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CONCLUSIONS

• NO SIGNIFICANT DIFFERENCE BETWEEN CIRCULAR AND RECTANGULAR CROSS SECTIONS

• EITHER ONE OF THE GEOMETRIES CAN BE USED CONTINGENT ON MANUFACTURABILITY