Patrick TABELING, ESPCI, MMN, Paris

Transcription

1 Patrick TABELING, ESPCI, MMN, Paris

2 Outline of Lecture History and prospectives of microfluidics 2 - Microsystems and macroscopic approach. 3 - The spectacular changes of the balances of forces as we go to the small world. Outline of Lecture 2 - The fluid mechanics of microfluidics - Digital microfluidics

3 Outline of Lecture Basic notions on diffusive processes 2 - Micromixing 3 - Microreactors. Outline of Lecture Electroosmosis, electrophoresis 2 - Miniaturisation of separation systems 3 - An example of a lab on a chip

4 Electrophoresis : Charged particles migrate Electroosmose : Fluid is driven by charged layers close to the walls Diélectrophoresis : Particles move under the effect a gradient of Electric field.

5 Using electric fields in miniaturized systems is easy because E~V/l

6 A FEW THINGS TO KNOW ABOUT ELECTROKINETICS 1 - Electrophoresis Coulomb law In a fluid, the flow equations are qe F v m dv dt 0 F qe F V 6 R V V e E with e q 6 R

7 z e

8 CHARACTERISTICS OF THE DEBYE HUCKEL LAYER Electrical Potential Thickness e z / D D D Debye-Huckel length

9 3) Electroosmosis = Flow of an electrolyte produced by the presence of an electric field driving the charged layer close to the walls z x Core u p E x Debye layers

10 u p E x Vitesse de Smoluchowsky

11 STREAMING POTENTIAL The inverse effect of electroosmosis U A flow generates an electric field

12

13 Principle of chromatography

14 Microfluidics and separation techniques The first separation experiment was done by Tswett (1902) This led to the discovery of chlorophylle. Column filled with particles Spinach leaves Disolved in toluen

15 Statistical model for chromatography Trapping times

16 5 fundamental types of chromatography

17 A typical equipment for HPLC

18 Electrophoretic separation For an isolated particle of charge q, mass m, Coulomb force reads : In a fluid, the charged particle move according to the law : Therefore F qe qe F v m dv dt 0 V e E where e F V 6 R V q 6 R Viscous friction Seperation is feasible, because ions with different ratio q/r will migrate at different speeds

19 Separation techniques using electric fields FSCE : Electrophoresis in a free medium E - CEC : Capillary Electro Chromatography (a gel is used) E - MEKC : Micellar ElectroKinetic chromatography

20 Un example of an electrochromatogram

21 How much the bands spread? U D eff t U Taylor Aris estimate D eff Pe 2 D U 2 b 2 /D

22 SOME IMPORTANT QUANTITIES USEFUL FOR THE CHARACTERIZATION OF THE PERFORMANCES OF THE SEPARATION TECHNIQUE

23 The number of theoretical plates N dis tan ce parcourue par la bande l argeur diffusive de la bande 2 N ~ D eff L 2 L / U ~ UL D eff (From M.C.Hennion (2004))

24 Retention time in the column N ~ UL ~ ULD D eff U 2 b ~ LD 2 Ub ~ t RD 2 b 2 Number of theoretical plates

25 OTHER QUANTITIES OF INTEREST (From M.C.Hennion (2004))

26 IS MINIATURIZATION ADVANTAGEOUS? 1) NON ELECTRICAL SEPARATION TECHNIQUES - Small samples - Intégration possible - Parallelism possible But no improvement of the analytical performances N ~ t RD b 2 ~ l 0 t R ~l/u~l 0

27 (From M.C.Hennion (2004))

28 Le premier lab on a chip était une colonne chromatographique à gaz (Terry, 1975)

29 2)Electrical separation techniques N ~ EOF EL D umber of theoretical plates Maximum electrical field that can be applied Q ~ K Tl ~ K E 2 l 3 Therefore E l 1 Thereby N~ l 0

30 The number of plates remains the same, while the retention time becomes : t R ~ L/V ~l 2 Conclusion : it is tremendously advantageous -Same performances, must smaller times -(800 s, Jacobson et al)

31 Miniaturization in this case thus leads to : - Small volumes - Intégration and parallélization possible - Conservation of the efficiency of the column - Considerable gain of time

32 (From M.C.Hennion (2004))

33 (From M.C.Hennion (2004))

34 (From M.C.Hennion (2004))

35 A microfluidic system for DNA separation From Agilent- Caliper Allow to characterize DNA Fragments with excellent Resolution, and in a small time

36 Miniaturization of electrophoretic separation systems Caliper

37 Miniaturization of electrophoretic separation systems QuickTime et un décompresseur H.263 sont requis pour visionner cette image. 200 m Experiment done by E. Brunet (MMN)

38 (From Kitamuri (2004)

39 SOME DEVELOPMENTS OF MICROFLUIDIC SYSTEMS DEDICATED TO SEPARATION

40 A novel method, based on microfluidics Big particles Move fast Small particles move slower

41 Institut Curie ESPCI

42 SAMPLE ANALYSIS IS AN IMPORTANT TOPICS IN MICROFLUIDICS. ALL SORTS OF SYSTEMS HAVE BEEN MICROFABRICATED

43 KITAMURI

44 KITAMURI

45 FIGURE S LAB ON A CHIP DEDICATED TO PROTEOMICS Inject ion was te 1 Separation channel Separation waste 2 1 nl sample injection 10 nl protein trapping module 100 nl rotary m icrom ixing module Pept ide out let Pressure control ler 0.2 b ar Protein sa mple 4 E lution buffer 5 Enzy me waste Pump Base ph 9 Enzy me ph 2 3 Enzy me act ivat ion modul e Regeneration buf fer 6 ESPCI Chip demonstrated with a Sample of FITC, Lysosyme, BSA

46 THIS WAS THE LAST TRANSPARENCY THANK YOU FOR YOUR KIND ATTENTION

47 The end