Udvikling, simulering og fabrikation

af mikroflowsystemer

Ulrich Krühne, PhD.

Center for Mikroteknologi og Overfladeanalyse

Små, mindre og mikroflow – og de særlige udfordringer

Seminar, Force Technology 17. marts 2010

Indhold

•Teknologisk Institut

•Fabrikation

•Simulering

•Praktiske problemer

•Cases

Danish Technological Institute

Brief description:

• Not-for-profit organisation approved by the Danish government

• Funded in 1906

• Employs ca.1000 people mainly scientist, engineers and technicians

• Turnover: 842 million DKK (2009)

• ca. 40 centres organised in eight divisions:

− Building technology

− Industry and Energy

− Informatics

− Materials (Centre for Microtechnology and Surface Analysis)

− Productivity and Logistics

− Industrial development

− Life Science

− Conferences and courses

Mission: to bridge the gap between science and industrial

application of new technologies

Om Instituttet

Technologies and know-how:

• Micro fluidic systems

− flow simulations, prototyping, 3D design, system integration, µ-dispensing

•Surface characterisation equipment for structural and chemical analysis

− SEM, FIB-SEM, EDX, TOF-SIMS, AFM

• Lasers for physical changes of surface structures

− CO2-, excimer- , femto second-, and diode lasers

• Sensor technology

− Wireless readout platform

• Surface treatment and deposition equipment

− MVD, PE-CVD, (ALD)

•Clean room alliance with Danchip at DTU Nanotech

− Nanoimprinting and more

Centre for Microtechnology and Surface Analysis

Om Instituttet

Centre for Microtechnology and Surface Analysis

Our aim is:

• to provide the industry with new processes based on nano- and

microtechnology suitable for low cost mass production.

• use our knowledge base to tailor surface properties to customer needs

• help customers to identify where enhanced surface properties adds

endproduct value

Om Instituttet

Fabrikation

•Laser ablation

• (CO2, Excimer, Femtosecond)

•Laser bonding (diode laser)

•Microdispensing

•Micromilling

•Cleanroom process (Nanoimprint….)

•CFD simulation services

•MVD microfactory

•Robot assisted dispensing/bonding

•Microfluidic test platform

•Experience in micro-fluidic cell handling

•Experience in immuno-assays

•Experience in DNA hybridisation

•Fabrication of optical microstructures

•Micro-magnetic separation in MFS

Fabrikation eksempler

Fabrikation

Fabrikation eksempler

PET

PEEK

Replica

SU8

Excimer Laser

PET PTFE

Steel Steel

Teflon

Glass

Eksempler fs laser

Non Newtonian Fluids

Multiple Phase Flows

Surface reactions and multi-component flows

Evaporation

Coupling of velocity fields and magnetic fields and heat transfer

Computational Fluid Dynamics – The principle

Simulering

Can we trust the results?

Or the hard way of learning….

Das Autobone Projekt Contract No. 505711-1

Medical technology - Tissue Engineering

Materials technology on micro- and nano-level

Stem cell Bioreactor

Activation of scaffold surfaces,

through impregnation with active

substances/plasma activation, in

order to achieve specific cell

adhesion

Production unit for the decentralised engineering of autologous cell

based osteoinductive bone substitutes: AUTOBONE

A real scaffoldNaseem Theilgaard, Medical Devices, at the Danish

Technological Institute

Number of pores = 34

Total area = 23595 pixel

Pore area = 12305 pixel

Relative Pore Area = 0.5215Number of pores = 12

Total area = 14410 pixel

Pore area = 9407 pixel

Relative Pore Area = 0.6525Number of pores = 5

Total area = 2940 pixel

Pore area = 487 pixel

Relative Pore Area = 0.1656

FSI in Detail

Biological fluid structure interaction model

BMr

SO

BMd

rSrO

SO

Xr

KK

Xk

YY

YY BM

S

S

2O2

O2max

2

2

SO2BM

Xfwfactor ratestrain FactorC

C

C

C 1

1

nrespiratio eMaintenanc

Growth

Decay

______________________________________________________________________________________

vectorRate C C X Process

Parameter Value Units

µmax 3 kg m-3 s-1

Arbitrary wall function fw = 1 for XW >=1.10-5

fw = 0 for XW <1.10-5

1

Decay rate kd = 0.1 kg m-3 s-1

Factor 0 for XBM ≥ 0.95

1 for XBM < 0.95

1

1

Oxygen respiration rate for

maintenance

YrO2 = 1 kg m-3 s-1

Oxygen saturation

concentration

KO2 = 0.05 1

Respiration rate rr = 1 kg m-3 s-1

Stoichiometric coefficient for

oxygen throughout growth

YO2 =1 1

Stoichiometric coefficient for

substrate throughout growth

YS = 1 1

strain rate factor Shear Strain Rate < 218 → SSF = 0,00459 [s].SSRShear Strain Rate > 218 →SSF = -0,00459 [s].SSR+2

1

1

Substrate respiration rate for

maintenance

YrS = 1 kg m-3 s-1

Substrate saturation

concentration

KS = 0.05 1

νapp 5.10-3 1 XBM ≥ 0.95

1.10-3 1 XBM < 0.95

kg m-1 s-1

kg m-1 s-1

Component Symbol Units

Arbitrary wall

concentration

XW 1

Biomass

concentration level

XBM 1

Oxygen

concentration Level

CO2 1

Substrate

concentration level

CS 1

Table 3. Components of the biological model

Table 1. Biological model

Table 2. Model Parameters

Shear or no shear?

Evolutionary strategy for implant optimisation

Fact: Biological experiments have shown that cell grow better due to perfusion

Assumption: We know the optimal shear stress level and the model is sufficient

Geometry

Definition of Geometry - definition of boundary conditions – simulation – post processing –

calculation of cost function

Fluid – Solid Interaction Study

calculation of cost function Σ

Stochastic variation of geometry

Definition of boundary conditions – simulation – post processing – calculation of cost

function

calculation of new cost function Σnew

Σnew < Σtrue false

Keep geometry

n n

Transient changes of the geometry

Praktiske Problemer

Bubbles, the friend of

every person dealing with

microfluidics

Praktiske Problemer

Sometimes you can even

use them for something

Like e.g. ink/laser-jet printers

Sample separation

Praktiske Problemer: Bobbler

Whre do we see them?

•Pumps

•Flow splitter

•Injection ports

•Temperature changes

•Different surface energies in surfaces

•Too hydrophilic systems

e.g. syringes

Gas solubility = function

Of temperature

Fill hydrophob

2nd fill

Praktiske Problemer: Bobbler

How to get rid of them?

•Good Priming (high speed)

•Surface tension reduction (Tween 20/50 soap)

•Dissolve them

•Pressure changes

•Good surface characteristics

•If you have bubbles and cells the bubbles function as lawn-mower…

Cases

Cases Mikrodsipensering

Left 2,5 µL evaporation of

Na-Fl stained water

Right 60 pico litre evaporation of

Na-Fl stained water

Intensity profiles of the figures

125 µm125 µm

Contact

Ulrich Krühne

Teamleder Microfluidics

Gregersensvej 6H, 2630 Taastrup

UKR@teknologisk.dk

+45 7220 3302

http://www.teknologisk.dk/specialister/22769