Udvikling, simulering og fabrikation af mikroflowsystemer. Ulrich Krühne, PhD. Center for Mikroteknologi og Overfladeanalyse

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1 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

2 Indhold Teknologisk Institut Fabrikation Simulering Praktiske problemer Cases

3 Om Instituttet 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

4 Om Instituttet Centre for Microtechnology and Surface Analysis 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 CO 2 -, 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

5 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

6 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

7 Fabrikation eksempler

8 Fabrikation

9 Fabrikation eksempler

10 Excimer Laser PET SU8 Replica PEEK

11 Eksempler fs laser PET PTFE Teflon Steel Steel Glass

12 Simulering Computational Fluid Dynamics The principle Non Newtonian Fluids Multiple Phase Flows Surface reactions and multi-component flows Evaporation Coupling of velocity fields and magnetic fields and heat transfer

13 Can we trust the results? Or the hard way of learning.

14 Das Autobone Projekt Contract No Production unit for the decentralised engineering of autologous cell based osteoinductive bone substitutes: AUTOBONE 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

16 A real scaffold Naseem Theilgaard, Medical Devices, at the Danish Technological Institute Number of pores = 34 Total area = pixel Pore area = pixel Relative Pore Area = Number of pores = 12 Total area = pixel Pore area = 9407 pixel Relative Pore Area = Number of pores = 5 Total area = 2940 pixel Pore area = 487 pixel Relative Pore Area =

17 FSI in Detail

18 Biological fluid structure interaction model Parameter Value Units µ max 3 kg m -3 s -1 Process Decay Growth Maintenance respiration X 1 BM 1 C Y Y O2 O2 ro2 C Y Y S S rs max C O2 C O2 K O2 CS C K S Rate vector S k r d r X X BM Factor strain rate factor fw BM X BM Arbitrary wall function fw = 1 for X W >= fw = 0 for X W < Decay rate k d = 0.1 kg m -3 s -1 Factor 0 for X BM for X BM < 0.95 Oxygen respiration rate for maintenance Y ro2 = 1 kg m -3 s Table 1. Biological model Oxygen saturation concentration K O2 = Respiration rate r r = 1 kg m -3 s -1 Stoichiometric coefficient for oxygen throughout growth Y O2 =1 1 Component Symbol Units Arbitrary wall concentration X W 1 Stoichiometric coefficient for substrate throughout growth Y S = 1 1 Biomass concentration level X BM 1 strain rate factor Shear Strain Rate < 218 SSF = 0,00459 [s]. SSR Shear Strain Rate > 218 SSF = -0,00459 [s]. SSR Oxygen concentration Level C O2 1 Substrate respiration rate for maintenance Y rs = 1 kg m -3 s -1 Substrate concentration level C S 1 Substrate saturation concentration K S = Table 3. Components of the biological model ν app X BM X BM < 0.95 Table 2. Model Parameters kg m -1 s -1 kg m -1 s -1

19 Shear or no shear?

20 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

21 Fluid Solid Interaction Study n Definition of Geometry - definition of boundary conditions simulation post processing calculation of cost function 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 n Keep geometry true Σnew < Σ false

22 Transient changes of the geometry

23 Praktiske Problemer Bubbles, the friend of every person dealing with microfluidics

24 Praktiske Problemer Sometimes you can even use them for something Like e.g. ink/laser-jet printers Sample separation

25 Praktiske Problemer: Bobbler Whre do we see them? e.g. syringes Pumps Flow splitter Injection ports Temperature changes Different surface energies in surfaces Too hydrophilic systems Gas solubility = function Of temperature Fill hydrophob 2 nd fill

26 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

27 Cases

28 Cases Mikrodsipensering Left 2,5 µl evaporation of Na-Fl stained water Right 60 pico litre evaporation of Na-Fl stained water 125 µm 125 µm Intensity profiles of the figures

29 Contact Ulrich Krühne Teamleder Microfluidics Gregersensvej 6H, 2630 Taastrup

Fraunhofer Institute for Material and Beam Technology

Laser Micro Processing Dr. Udo Klotzbach Fraunhofer Institute for Material and Beam Technology Dresden Overview Equipment - CO 2 -lasers - Solid state lasers (Nd:YAG, Disk, Fiber) - Diode lasers - Excimer