ME2082 Dr. Wang Class Project Presenter: Susan Felixqiw4/Academic/ME2082/Student...Non-Moving Actuation: Electro-osmosis! Electro-osmotic Conductivity, based on material properties!

MOVING AND NONMOVING AND NON--MOVING MICRO MOVING MICRO PUMPS FOR FLUID DELIVERY: PUMPS FOR FLUID DELIVERY:

A STUDY OF CURRENT A STUDY OF CURRENT TECHNOLOGIESTECHNOLOGIES

ME2082ME2082Dr. WangDr. Wang

Class Project Class Project Presenter: Susan Felix Presenter: Susan Felix

IntroductionIntroduction

!! MicropumpMicropump History History !! In existence since before 1970sIn existence since before 1970s

!! MEMS and Biotech MEMS and Biotech

!! Medical Medical MicrofluidicsMicrofluidics!! Drug Delivery Drug Delivery

!! External Placement External Placement !! Internal Placement Internal Placement

Biotechnology, Drug Delivery and Biotechnology, Drug Delivery and Market Needs Market Needs

!! Drug Therapy Drug Therapy !! Better delivery performanceBetter delivery performance

!! More sophisticated drugs More sophisticated drugs !! Cost Cost

!! Necessity Necessity !! Medical Errors due to human mistakesMedical Errors due to human mistakes

!! Procedure Reduction Procedure Reduction !! More reliable More reliable

Biotechnology, Drug Delivery and Biotechnology, Drug Delivery and Market NeedsMarket Needs

!! Convenience and Patient ConcernsConvenience and Patient Concerns!! More regular medicine dosage More regular medicine dosage

!! Diabetes/InsulinDiabetes/Insulin!! AlzheimerAlzheimer’’s s

!! More comfortable placementMore comfortable placement

NonNon--Moving Actuation: Moving Actuation: ElectroElectro--osmosisosmosis

!! What is electroWhat is electro--osmosis?osmosis?!! Flow of liquid in contact with a solid surface induced by an Flow of liquid in contact with a solid surface induced by an

applied tangential electric fieldapplied tangential electric field!! Diffuse layer begins to move in response to the electric Diffuse layer begins to move in response to the electric

forces of the ionic charges, drag and push the liquid forces of the ionic charges, drag and push the liquid surrounding them, producing liquid flow surrounding them, producing liquid flow

!! Why electroWhy electro--osmosis?osmosis?!! Minimal wear with no moving partsMinimal wear with no moving parts!! InexpensiveInexpensive!! DisposableDisposable


!! ElectroElectro--osmosis Fluid Velocityosmosis Fluid Velocity!! HelmholzHelmholz--SmoluchowskiSmoluchowski EquationEquation!! Developed by Chang and Kang Developed by Chang and Kang


!! ElectroElectro--osmotic Conductivity, based on material propertiesosmotic Conductivity, based on material properties!! TortuosityTortuosity of the material is defined as (Le/L)of the material is defined as (Le/L)

!! Zeta potential of the given material is the potential at the Zeta potential of the given material is the potential at the intermediate node of a potential divider, formed by the capacitaintermediate node of a potential divider, formed by the capacitance nce at the diffuse layerat the diffuse layer


!! How is flow rate changed in EO?How is flow rate changed in EO?!! Flow rate can be increased by Flow rate can be increased by

!! increasing the electroincreasing the electro--osmotic conductivity (changing material osmotic conductivity (changing material properties necessary to calculate properties necessary to calculate kkee

!! decreasing the conductivity of the materialdecreasing the conductivity of the material!! increasing the currentincreasing the current


!! Fluid FlowFluid Flow!! Piston type Actuation Piston type Actuation !! Laminar flow Laminar flow !! Diffuse layerDiffuse layer

!! Dependent on conduction, can vary in size Dependent on conduction, can vary in size


!! Variation parameters that affect flow rateVariation parameters that affect flow rate!! Channel size and cross sectional areaChannel size and cross sectional area


!! Increasing flow rate Increasing flow rate !! Increasing the ratio of circumference to its cross sectional areIncreasing the ratio of circumference to its cross sectional area (C/A a (C/A

value)value)!! The C/A value for the capillary on the left is 4x10The C/A value for the capillary on the left is 4x1055 and the C/A value for and the C/A value for

the capillary on the right is 8x10the capillary on the right is 8x1044. I is expected that the capillary on the . I is expected that the capillary on the right would have better pump performance.right would have better pump performance.


!! Researchers at Stanford working in conjunction with Researchers at Stanford working in conjunction with Intel, have found that the cross sectional area of the Intel, have found that the cross sectional area of the pump can be made arbitrarily large by increase the pump can be made arbitrarily large by increase the number of slots. number of slots.


!! Prototype of silicon electroPrototype of silicon electro--osmotic pump osmotic pump developed at Stanford Universitydeveloped at Stanford University


!! Research in Academia Research in Academia !! Testing Methods Testing Methods

!! Small flow ratesSmall flow rates!! Small outlet/inlet Small outlet/inlet

Moving Actuation: Peristaltic Pump Moving Actuation: Peristaltic Pump

!! Reduction in the number of moving parts or Reduction in the number of moving parts or surfaces compared to reciprocating pumpsurfaces compared to reciprocating pump

!! Reduction in wear and fatigue failures of these Reduction in wear and fatigue failures of these pumps compared to reciprocating pumpspumps compared to reciprocating pumps

!! Already used on a macro scale Already used on a macro scale

Moving Actuation: Peristaltic PumpMoving Actuation: Peristaltic Pump!! How do peristaltic pumps work?How do peristaltic pumps work?

!! One method One method –– piezopiezo disksdisks

Moving Actuation: Peristaltic PumpMoving Actuation: Peristaltic Pump

!! Piezoelectric Effect and Peristaltic PumpsPiezoelectric Effect and Peristaltic Pumps!! Converse effectConverse effect

!! Applied voltage deforms the Applied voltage deforms the piezopiezo material material

!! Materials Materials !! Ceramics, single crystals, polymers, composites or films. Ceramics, single crystals, polymers, composites or films.


!! Characteristic EquationsCharacteristic Equations!! DeformationDeformation

!! StrainStrain


!! Alternate Methods for Creating Motion Alternate Methods for Creating Motion -- Membranes Membranes


!! Governing Equations for Electrostatic ActuationGoverning Equations for Electrostatic Actuation!! permittivity, cross sectional area, spring constant, permittivity, cross sectional area, spring constant,

voltage and gap distance between electrodes are the voltage and gap distance between electrodes are the independent variables within the systemindependent variables within the system

!! Threshold VoltageThreshold Voltage

!! Electrostatic PressureElectrostatic Pressure


!! Governing Equations for Electrostatic ActuationGoverning Equations for Electrostatic Actuation!! Spring Constant for Membrane (dependent on Spring Constant for Membrane (dependent on

membrane geometry)membrane geometry)

!! ImpedanceImpedance


!! Manufacturing AbilitiesManufacturing Abilities!! Pump chambers in the silicon disk Pump chambers in the silicon disk

!! Ion etching system on a polished silicon wafer. Ion etching system on a polished silicon wafer.

!! Utilized in the super conductor industry. Utilized in the super conductor industry.

!! Inlet and outlet ports on the glass Inlet and outlet ports on the glass !! Precision sand blasted with particles of sandPrecision sand blasted with particles of sand

!! Parts are Parts are anodicallyanodically bonded togetherbonded together


!! Anodic BondingAnodic Bonding!! Displace ions from the glass Displace ions from the glass

surface at elevated surface at elevated temperatures by an electric temperatures by an electric fieldfield

!! Glass becomes highly reactive Glass becomes highly reactive reactivereactive with the silicone with the silicone surface and forms a chemical surface and forms a chemical bondbond

!! Information on this bonding is Information on this bonding is readily available in both the readily available in both the academic and commercial academic and commercial fields,fields,

!! Manufacturing method is Manufacturing method is viable and sustainable. viable and sustainable.


!! Moving PartsMoving Parts!! More wear than EO pumpsMore wear than EO pumps

!! Possible decrease in Possible decrease in reliablityreliablity!! Trap air/other particlesTrap air/other particles

!! FEA (ANSYS) FEA (ANSYS) !! CFD CFD

Compare and ContrastCompare and Contrast

!! Drug Delivery PerformanceDrug Delivery Performance

!! Flow rate and Pressure Flow rate and Pressure !! Control the flow of the fluid to the patient. Control the flow of the fluid to the patient. !! Speedy and accurate delivery is highly desired Speedy and accurate delivery is highly desired

!! Protecting fluids with suspended cells or Protecting fluids with suspended cells or microspheresmicrospheres by considering shear stressby considering shear stress

!! Must reliably prevent clogging. Must reliably prevent clogging.

Compare and ContrastCompare and Contrast!! NonNon--moving pumps are represented by pink squares moving pumps are represented by pink squares

and trianglesand triangles!! Faster flow rates at 0.01 Faster flow rates at 0.01 atmatm to 1 to 1 atmatm!! Higher pressures at low flow rates Higher pressures at low flow rates

!! Mechanical moving pumps by green circlesMechanical moving pumps by green circles

Compare and ContrastCompare and Contrast

!! Flow Rate vs. Pressure for micro diaphragm pump at Flow Rate vs. Pressure for micro diaphragm pump at varying frequencies varying frequencies

!! Flow Rate vs. Pressure for EO pump at varying Flow Rate vs. Pressure for EO pump at varying frequenciesfrequencies

Current Market ProductsCurrent Market Products

!! DebiotechDebiotech!! ChronojectChronoject

!! Silicon and anodic wafer binding Silicon and anodic wafer binding

!! Insulin PumpInsulin Pump!! Sensors for Air/ParticulateSensors for Air/Particulate!! Low flow rates (1 ml/min)Low flow rates (1 ml/min)!! 90% yield manufacturing90% yield manufacturing


!! ParticleParticle--laden Deliveryladen Delivery!! FlamelFlamel, Inc., Inc.

!! Drug material in the lower intestine, has produced Drug material in the lower intestine, has produced small molecule drugssmall molecule drugs

!! Drug delivery in childrenDrug delivery in children

!! Need small particle delivery, delivered over a longer Need small particle delivery, delivered over a longer period of timeperiod of time

Current Market ProductsCurrent Market Products!! ParticleParticle--laden Deliveryladen Delivery

!! SarcosSarcos -- Domino Domino MicropumpMicropump!! Programmable delivery through a microprocessor Programmable delivery through a microprocessor

!! Drug delivery to human patients for pharmacological Drug delivery to human patients for pharmacological and toxicological testing and toxicological testing

!! Parasite control and other applications for animalsParasite control and other applications for animals

!! Work in conjunction with catheters for taking biopsies Work in conjunction with catheters for taking biopsies of and surgeries for breast cancer.of and surgeries for breast cancer.


!! Passive Check ValvesPassive Check Valves!! ThinXXsThinXXs MicropumpMicropump

!! PiezoPiezo diaphragm pump with passive check valvesdiaphragm pump with passive check valves!! Flow rate of the fluid is controlled by the frequency Flow rate of the fluid is controlled by the frequency

necessary to activate the piezoelectric material necessary to activate the piezoelectric material

Future TrendsFuture Trends

!! Analytical tools Analytical tools !! Finite element (FEA) Finite element (FEA) !! Computational fluid dynamics (CFD) Computational fluid dynamics (CFD) !! Used to improve current designs to increase strength of the Used to improve current designs to increase strength of the

micro pump or perform an inmicro pump or perform an in--depth study of the flow pattern depth study of the flow pattern through the pump. through the pump.

!! Development to improve the designs can happen at a faster Development to improve the designs can happen at a faster pace through computer simulation software. pace through computer simulation software. !! model several different surface areas or flow patterns model several different surface areas or flow patterns !! solid material in liquids can be simulated in flow scenarios to solid material in liquids can be simulated in flow scenarios to

determine if the shear stress generated in the pump will destroydetermine if the shear stress generated in the pump will destroy the the materialsmaterials

ConclusionsConclusions

!! There is a market need for There is a market need for micropumpsmicropumps in the field of in the field of medical drug deliverymedical drug delivery

!! Past designs have been large and bulky. Past designs have been large and bulky.

!! Advent of advanced medicine, pumps that can precisely Advent of advanced medicine, pumps that can precisely and accurately deliver drugs to a patient are needed.and accurately deliver drugs to a patient are needed.

!! As the size of pumps in development get smaller, pump As the size of pumps in development get smaller, pump performance is becoming specific, with no pump that performance is becoming specific, with no pump that can clearly handle all applications. can clearly handle all applications.


!! Peristaltic PumpsPeristaltic Pumps!! Well documented on a macro scale. Well documented on a macro scale. !! Peristaltic pumps use a simple method to push fluid by a Peristaltic pumps use a simple method to push fluid by a

series of consecutive movementsseries of consecutive movements!! The downfall of a peristaltic pump is the amount of The downfall of a peristaltic pump is the amount of

mechanical moving parts. mechanical moving parts. !! These parts present not only reliability concerns from wear and These parts present not only reliability concerns from wear and

degeneration of material over timedegeneration of material over time!! Present a point for fluids with suspended particles to become clPresent a point for fluids with suspended particles to become clogged ogged

and prevent the pump from working as intended. and prevent the pump from working as intended.

!! Manufacturing still being developed, but based on already Manufacturing still being developed, but based on already existing technologyexisting technology

ConclusionsConclusions!! ElectroElectro--osmosis pumps will most likely evolve to osmosis pumps will most likely evolve to

produce pressures and flow rates neededproduce pressures and flow rates needed!! Peristaltic pumps, through means of membranePeristaltic pumps, through means of membrane--like like

parts or other means will continue to produce the parts or other means will continue to produce the desired flow rates and pressures while reducing shear desired flow rates and pressures while reducing shear stress and other factors detrimental to fluids containing stress and other factors detrimental to fluids containing microspheresmicrospheres. .

!! Both fields of micro pumps are still mainly in research Both fields of micro pumps are still mainly in research arena, it is expected that the pump technology that arena, it is expected that the pump technology that overtakes the consumer market will be that which is overtakes the consumer market will be that which is proven reliable proven reliable -- not only in a performance manner, not only in a performance manner, but also in a manufacturing sense. but also in a manufacturing sense.


!! ElectroElectro--osmosis osmosis !! System is very simple and contains no moving partsSystem is very simple and contains no moving parts

!! Pumps are limited in materials used in the Pumps are limited in materials used in the construction of the capillary, as well as fluids they construction of the capillary, as well as fluids they are capable of delivering. are capable of delivering.

!! The pressures and flow rates produced are similar to The pressures and flow rates produced are similar to those produced by moving part pumps such as those produced by moving part pumps such as peristaltic and restriction.peristaltic and restriction.

!! Manufacturing still being developedManufacturing still being developed

Questions? Questions?

Documents

ME2082 Dr. Wang Class Project Presenter: Susan Felixqiw4/Academic/ME2082/Student...Non-Moving Actuation: Electro-osmosis! Electro-osmotic Conductivity, based on material properties!