Liquid Marble Based Digital Microfluidics: Fundamental Physics and Applications

Liquid marble based digital microfluidics: fundamental physics and applications

Nam-Trung Nguyen Queensland Micro and Nanotechnology Centre Griffith University, Nathan Campus Email: [email protected]

Lab webpage: https://ntnlab.com

4BIO SUMMIT: EUROPE 2018 1 Queensland Micro- and Nanotechnology Centre (QMNC) www.griffith.edu.au/qmnc

• ~ 30 Academic members • ~ 60 PhD students • A$3.0 Mil annual external funding • Class 100 and 1000 clean rooms

Microtechnology Nanotechnology (Top-down) (Bottom-up)

Micro/nanosystems (Multidisciplinary)

4BIO SUMMIT: EUROPE 2018 2 Micro/nanofluidics as tool for cellular and molecular scales

Human E-coli Hand bacterium Red blood Hemoglobin Hair strand HIV cell

1Å 1nm 10nm 100nm 1mm 10mm 100mm 1mm 1cm 10cm 1m

Nanofluidic tools Microfluidic tools

Petri dish

Well plate Liquid marble

4BIO SUMMIT: EUROPE 2018 Cell Stretcher Chip 3 Droplet versus liquid marble

Droplet Liquid marble

• Wetting behavior strongly depends • Non wetting on the surface property • Behavior independent from surface • Liquid-gas-solid system • Liquid-solid-gas system • We used 1 um PTFE powder

4BIO SUMMIT: EUROPE 2018 4 Applications of liquid marble based digital microfluidics

4BIO SUMMIT: EUROPE 2018 5 Liquid marble as bioreactor for cell spheroids (3D cell culture)

R.K. Vadivelu, C.H. Ooi, R.Q. Yao, J.T. Velasquez, E. Pastrana, J. Diaz-Nido, F. Lim, J. Ekkberg, N.T. Nguyen, J. St John, Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles, Scientific Reports, 2015, Vol. 5, pp. 15083 4BIO SUMMIT: EUROPE 2018 6 Sessile versus floating liquid marble

4BIO SUMMIT: EUROPE 2018 7 Quality of cell spheroids grown in liquid marbles

Spheroids of different sizes: (A) 60 μ m diameter spheroid, (B) 100 μm, (C) 150 μm. (D–G) Immunostaining of spheroids from floating LMs grown for 24 h at a seeding density of 5×103 cells/10 μ L: (D) GFP-expressing OECs, (E) s100β immunostaining, (F) DAPI and (G) merged image. Co-culture of OECs with Schwann cells and with astrocytes. Marbles were seeded with the two different cell types at a ratio of 1:1 with an overall seeding density of 500 cells/μL and cultured for 48 h: (H) OECs (green) with Schwann cells (red) and (I) OECs (green) with astrocytes (red). 4BIO SUMMIT: EUROPE 2018 8 Sessile liquid marble for culturing toroid tissue

R. K. Vadivelu, H. Kamble, A. Munaz, N.-T. Nguyen, Liquid Marble as Bioreactor for Engineering Three- Dimensional Toroid Tissues, Scientific Reports, 2017, Vol. 7, pp. 12388.

4BIO SUMMIT: EUROPE 2018 9 Sessile liquid marble for culturing toroid tissue

3D wound closure model

R. K. Vadivelu, H. Kamble, A. Munaz, N.-T. NguyenLiquid Marble as Bioreactor for Engineering Three- Dimensional Toroid Tissues, Scientific Reports, 2017, Vol. 7, pp. 12388.

4BIO SUMMIT: EUROPE 2018 10 Floating liquid marble as in-vitro injury model

Mixing olfactory ensheathing cells (OECs) with nerve debris

R. K. Vadivelu, H. Kamble, A. Munaz and N.-T. NguyenLiquid marbles as bioreactors for the study of three- dimensional cell interactions, Biomedical Microdevices, 2017, Vol. 19, No. 2, pp. 31.

4BIO SUMMIT: EUROPE 2018 11 Cryoprotectant-free freezing of cells

Freezing Thawing Cell viability post-thawing A B C

D E F

Submitted to ACS Aplied Materials & Interfaces

4BIO SUMMIT: EUROPE 2018 12 Evaporation behaviour of liquid marbles

4BIO SUMMIT: EUROPE 2018 13 Evaporation of a sessile liquid marble

C.H. Ooi, E. Bormashenko, A.V. Nguyen, G. Evans, D.V. Dao, N.-T. Nguyen, Evaporation of ethanol-water binary mixture sessile liquid marbles, Langmuir, 2016, Vol. 32, No. 24, pp. 6097-6104.

4BIO SUMMIT: EUROPE 2018 14 Evaporation of a sessile liquid marble with a binary solution

Mass change of a water/ethanol droplet Mass change of a water/ethanol liquid due to evaporation marble due to evaporation

C.H. Ooi, E. Bormashenko, A.V. Nguyen, G. Evans, D.V. Dao, N.-T. Nguyen, Evaporation of ethanol-water binary mixture sessile liquid marbles, Langmuir, 2016, Vol. 32, No. 24, pp. 6097-6104.

4BIO SUMMIT: EUROPE 2018 15 Evaporation of multiple liquid marbles at elevated temperature

K. R. Sreejith, C. H. Ooi, D. V. Dao and N.-T. Nguyen,Evaporation dynamics of liquid marbles at elevated temperatures, RSC Advances, 2018, Vol. 8, No. 28, pp. 15436-15443 4BIO SUMMIT: EUROPE 2018 16 Evaporation of liquid marbles at elevated temperature

4BIO SUMMIT: EUROPE 2018 17 Deformation of liquid marbles

4BIO SUMMIT: EUROPE 2018 18 Deformation of a sessile liquid marble

Small liquid marble (Bo<<1)

Large liquid marble (Bo>>1)

N.T. NguyenDeformation of ferrofluid marbles in the presence of a permanent magnet, Langmuir, Vol. 29, No. 45, 2013, pp. 13982-13989.. 4BIO SUMMIT: EUROPE 2018 19 Deformation of a sessile liquid marble

Using ferrofluid to form liquid marble and magnet to increase the deforming force

N.T. NguyenDeformation of ferrofluid marbles in the presence of a permanent magnet, Langmuir, Vol. 29, No. 45, 2013, pp. 13982-13989.. 4BIO SUMMIT: EUROPE 2018 20 Deformation of a sessile liquid marble

Magnetic Bond number

Small liquid marble

Large liquid marble

N.T. NguyenDeformation of ferrofluid marbles in the presence of a permanent magnet, Langmuir, Vol. 29, No. 45, 2013, pp. 13982-13989.. 4BIO SUMMIT: EUROPE 2018 21 Compression of a liquid marble

εε == hh 00 εh= 0.17

εh= 0.32 εh= 0.5 Experiment Simulation

Normalised stress 휎 휎*= 휎0 Strain

2푟0−ℎ 휀ℎ = 2푟0

Unpublished results, submitted to APL * 2 σ Bo = 0.6[1/(1-εhro) -1] 4BIO SUMMIT: EUROPE 2018 22 Deformation of a floating liquid marble

Floating and a liquid surface reduces evaporation of a liquid marble

3D X-ray tomography

C.H. Ooi, C. Plackowski, A.V. Nguyen, R.K. Vadivelu, J. A. St John, D.V. Dao, N.-T. Nguyen, Floating mechanism of a small liquid marble, Scientific Reports, 2016, Vol. 6, pp. 21777. 4BIO SUMMIT: EUROPE 2018 23 Floating mechanism of a small liquid marble

0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 0.4 0.5 Bond number Bo Bond number Bo

C.H. Ooi, C. Plackowski, A.V. Nguyen, R.K. Vadivelu, J. A. St John, D.V. Dao, N.-T. Nguyen, Floating mechanism of a small liquid marble, Scientific Reports, 2016, Vol. 6, pp. 21777.

4BIO SUMMIT: EUROPE 2018 25 Magnetically actuated liquid marbles

4BIO SUMMIT: EUROPE 2018 26 Magnetic actuation of sessile marbles

N.T. NguyenDeformation of ferrofluid marbles in the presence of a permanent magnet, Langmuir, Vol. 29, No. 45, 2013, pp. 13982-13989..

4BIO SUMMIT: EUROPE 2018 27 Magnetic actuation of floating marbles

Water strider - floating by surface tension

M. K. Khaw, C. H. Ooi, F. Mohd-Yasin, R. Vadivelu, J. St John and N.-T. Nguyen, Digital microfluidics with a magnetically actuated floating liquid marble, Lab on a Chip, 2016, Vol. 16, No. 12, pp. 2211-2218.

4BIO SUMMIT: EUROPE 2018 28

Dependence from field strength

B = 10.1 mT 10.1 = B

Field strength Field Magnet distance Magnet

Measured displacement and velocity of a 5 μL floating liquid marble with an iron oxide concentration of 3 mg/ml

and a velocity of the permanent magnet of 0.465 mm s−1 mT 3.09 = B with increasing distance from the magnet; (a) d = 6 mm (B = 10.1 mT); (b) d = 10 mm (B = 3.09 mT); and (c) d = 16 mm (B = 0.96 mT). 4BIO SUMMIT: EUROPE 2018 29

Dependence on iron oxide concentration

5 5

Concentration

3 3

= c

Measured displacement and velocity of a 5 μL floating marble at a distance of 10 mm from the permanent magnet and a velocity of the permanent magnet of 1.86 mm/s with decreasing iron oxide concentration: (a) c = 5 mg/ml; (b) c = 3 mg/ml; and (c) c = 1 mg/ml. 4BIO SUMMIT: EUROPE 2018 30 Operation map for magnetically actuated liquid marbles

Operation map with the three regimes: sliding (*), lagging (♦) and dislodgement (○). (a) Distance from the magnet and magnet speed space at c = 3 mg/ml; (b) distance from the magnet and magnet speed at c = 5 mg/ml; and (c) iron oxide concentration and speed space.

4BIO SUMMIT: EUROPE 2018 31 Friction factor of moving floating marbles – capillarity driven experiment

C. H. Ooi, A. V. Nguyen, G. M. Evans, D. V. Dao, N.-T. Nguyen, Measuring the Coefficient of Friction of a Small Floating Liquid Marble, Scientific Reports, 2016, Vol. 6, pp. 38346. 4BIO SUMMIT: EUROPE 2018 32 Friction factor of moving floating marbles

C. H. Ooi, A. V. Nguyen, G. M. Evans, D. V. Dao, N.-T. Nguyen, Measuring the Coefficient of Friction of a Small Floating Liquid Marble, Scientifc Reports, 2016, Vol. 6, pp. 38346.

4BIO SUMMIT: EUROPE 2018 33 Friction factor of moving floating marbles – magnetically driven experiment

M. K. Khaw, C. H. Ooi, F. Mohd-Yasin, A. V. Nguyen, G. M. Evans and N.-T. NguyenDynamic behaviour of a magnetically actuated floating liquid marble, Microfluidics and Nanofluidics, 2017, Vol. 21, No. 110, pp. 1- 12. 4BIO SUMMIT: EUROPE 2018 34 Capillarity actuated liquid marbles

4BIO SUMMIT: EUROPE 2018 35 Drunken droplet: self-deriven liquid marble

• Liquid marble loaded with ethanol • Ethanol evaporation and dissolution in the carrier fluid causes Marrangoni effect • Liquid marble moves autonomously until the fuel is exhausted

Ethanol+Water

Marangoni flow

Water

4BIO SUMMIT: EUROPE 2018 36 Motion phases and duration

(iii) Decaying phase (iv) Complete stop Liquid marble with diluted ethanol Water

PMMA slab

(ii) Intermediate steady phase (i) Initial oscillatory phase

Petri dish

4BIO SUMMIT: EUROPE 2018 38 Manipulation of liquid marble using dielectrophoresis

Pick and place of 10 µl marble, at 6x real-time playback speed Pipette-like pick and place device supplied by a 9V battery. 4BIO SUMMIT: EUROPE 2018 39 Dragging a floating liquid marble using dielectrophoresis

Electrode Electrode

PMMA z holder PMMA holder FB FDEP

Air Liquid FDEP FS marble FD

r Liquid L r marble

Electric field lines Liquid Water surface z = 0 FW surface

DEP: Dielectrophoresis Driving force FDEP resolved into Fr and Fz D: Drag Horizontal direction (r) S: Surface tension Vertical direction (z) Ԧ Ԧ B: Buoyancy 푚푟퐿ሷ + 퐹퐷 + 퐹푟 = 0 퐹Ԧ퐵 + 퐹Ԧ푆 + 퐹Ԧ푧 − 퐹Ԧ푊 = 0 W: Weight 4BIO SUMMIT: EUROPE 2018 40 One-dimensional equation of motion

4 퐶 휋휌푅3푟ሷ + 6휋휇푅 2 푟ሶ + 2휋휀푅3 푈푑 2퐶 훻 훻휎 2 = 0 3 퐿 푧∗ 푛 퐿 1 푟 DEP driving force Inertia Stokes friction

1 ε − ε푤 / ε + ε푤 휎 = 1 + 1 2 2 2 2

푟퐷 + 푑 − 푧 2 푟퐷 + 푑 + 푧 2 5 mm/s 5

Dragging a 2.5-µl liquid marble at 3 kV 28 mm/s 28

4BIO SUMMIT: EUROPE 2018 41 Voltage/speed operation map

112/125 successful predictions

4BIO SUMMIT: EUROPE 2018 42 Coalescence of liquid marbles

J. Jin, C. H. Ooi, D. V. Dao and N.-T. Nguyen,Liquid marble coalescence via vertical collision, Soft Matter, 2018, Vol. 14, No. 20, pp. 4160-4168

4BIO SUMMIT: EUROPE 2018 43 Coalescence of liquid marbles

4BIO SUMMIT: EUROPE 2018 V=5 mL 44 Coalescence of liquid marbles V=10 mL

V=5 mL

V=10 mL

4BIO SUMMIT: EUROPE 2018 Condition for coalescence of liquid marbles

4BIO SUMMIT: EUROPE 2018 46 Conclusions

▪ Fundamentals: ▪ Evaporation comparable to droplet ▪ Slowing down evaporation by controlling humidity, e.g. floating ▪ Floating system has both deformed marble and deformed liquid surface ▪ Friction factor depends on the deformation ▪ Liquid marble can be actuated by magnetic, capillary and electrostatic forces ▪ Liquid marble coalesence by overcoming surface tension and breaking the coating ▪ Applications: ▪ Bio reactor for 3D cell culture ▪ Micro environment for mimicking in-vivo conditions ▪ Cryoprotectant-free freezing of cells

4BIO SUMMIT: EUROPE 2018 47 Liquid Marble Team

Former PhD Students and current Research Fellows • Dr. Chin Hong Ooi (Research fellow, Griffith Uni) • Dr. Raja Vadivelu (Research Fellow, Griffith Uni) • Dr. Mei Kum Khaw (Lecturer, Malaysia)

Current PhD Students • Jing Jin (China) • Sreejith K. R (India)

4BIO SUMMIT: EUROPE 2018 48