Microfluidics and nanofluidics involve the manipulation of fluids in channels with small dimensions, including cross-sectional areas less than 100 micrometers for microfluidics and the nanometer scale for nanofluidics. Key applications of microfluidics and nanofluidics include lab-on-a-chip systems, molecular biology, and the study of transport phenomena at small scales. Forces that dominate at the nanoscale include electrostatic, van der Waals, and capillary forces. Nanofluidic systems have potential applications in analytical chemistry, studying gene expression, and water purification.

1. MICROFLUIDICS and Nanofluidics
Presented by
Saakre Manjesh
Manglam Arya

2.  Fluid is a substance that continually flows under an
applied shear stress
 Fluidics: handling of liquids and/or gases
 Micro: has at least one of the following features:
• Small volumes
• Small size
• Low energy consumption
• Use of special phenomena

3. What is a micro-fluidic system?
• A system manipulating fluids in channels having cross section
dimension on less than 100 micro-meters
– Smallest micro-channel: Nano-tube
Micro-channels Nano-tubes

4. A microfluidic channel is about the
same width as a human hair, 70 μm

5. • Micro-Total-Analysis-Systems
(mTAS)
– One system to provide all of
the possible required analyses
for a given type problem
– All processing steps are
performed on the chip
– No user interaction required
except for initialization
• Lab-on-a-chip
• Micro-fluidics in nature
– Alveoli (Lung bubbles)

6. • Low sample and reagent consumption; fluid volumes (μl; nl;
pl; fl)
• Small physical and economic footprint
• Parallelization and high throughput experimentation
• Unique physical phenomena: use of effects in the micro-
domain:
 Laminar flow
 Capillary forces
 Diffusion

7. • Law: Conservation of
mass
• Law: Conservation of
momentum
• Assumption:
Incompressibility
• Assumption: No-slip
boundary
• condition, i.e. velocity of
the fluid flow at a surface
is zero

8. Basic Properties
Types of fluids:
• Newtonian fluids
• Non-Newtonian fluids
Types of fluid flow:
• Laminar
• Turbulent

9. Linear relationship between stress and strain, i.e. viscosity is
independent of stress and velocity
Rate of shearing strain, dv/dy

10. Non-Newtonian Fluids
• Non-linear relationship between shear stress and shear strain
• Examples: paint, blood, ketchup, cornstarch solution

11. • Viscosity is a measure of internal friction
(resistance) to flow

12. Laminar and Turbulent Flow
Laminar flow:
• Fluid particles move along smooth paths in layers
• Most of energy losses are due to viscous effects
• Viscous forces are the key players and inertial forces are negligible
Turbulent flow:
• An unsteady flow where fluid particles move along irregular paths
• Inertial forces are the key players and viscous forces are negligible

13. Laminar and Turbulent Flow

14. Reynolds number
• Measure of flow turbulence
• Used to help predict similar flow patterns in different
fluid flow situations.
• Re < 2000 for laminar
• Due to small dimensions
• Re < 1 in microfluidic systems

15. Couette flow:
• One of the plates moves parallel to the other
• Steady flow between plates
• No-slip condition applies

16. • Gives the pressure drop in an incompressible and newtonian
fluid in laminar flow flowing through a long cylindrical pipe
of constant section.
• Pressure-driven flow
• No-slip condition( A solid boundary, the fluid will have zero
velocity relative to boundary) applies

17. • Diffusion is the transport of particles from a
region of higher concentration to one of lower
concentration by random motion.

18. • Surface tension is a property of cohesion (the attraction of
molecules to like molecules)
• When an interface is created, the distribution of cohesive
forces is asymmetric
• Molecules at the surface may be pulled on more strongly by
bulk molecules

19. Wettability-degree of wetting
• wettability is determined by a force balance between adhesive
and cohesive forces.
• Adhesion vs. cohesion
• Contact angles are a way to measure liquid-surface
interactions
Hydrophobic Hydrophilic

21. Sample Loading
And Injection
Subatmospheric
Pressure
Chamber
Electro-Osmotic
Pump
Electro-Pneumatic
Distributor
Small Volume
Transport
Microfluidic
Devices
Micro-scale
Handling System

22. A microfluidic system for DNA separation
Allow to characterize DNA
Fragments with excellent
Resolution, and in a small
time
DNA micrototal analysis systems (mTAS)
have been made through the integration
of different processes, such as PCR,
separation and detection on a microscale.

23. Entropy recoilingEntropy trap

28. Continuous flow microfluidics
Droplet based Microfluidics
 Digital microfluidics
DNA chips (microarrays)
 Molecular biology
 Evolutionary biology
Cell behavior
Cellular biophysics
 Optics
 Acoustic droplet ejection (ADE)
Fuel cells
 A tool for cell biological research
 Future Directions
Key application areas

29.  Study of the behavior, manipulation, and control of fluids that are
confined to structures of nanometer
 Nanofluids are suspensions of nanoparticles in a base fluid, typically
water
 Emphasis is put on the very diverse background of nanofluidics in
biology, chemistry, physics and engineering and the valuable
knowledge available in these disciplines

30. Classical disciplines related to Nanofluidics and
some of the relevant subjects studied

31. Significant reduction in sample volumes required for analyses
 Enables experiments to be carried out that take advantage of
laminar flow conditions
 High surface to volume ratios
Low concentrations, molecular confinement, and low heat
capacity

32. Microfluidics Nano fluidics
Size- micrometer Size- Nanometer
Low Density high Density
Low
Surface area to volume ratio
High
Surface area to volume ratio
Low thermal conductivity High thermal conductivity
High particle clogging and
sedimentation
Low particle clogging and
sedimentation
Stability- Comparatively less Stability- High

33. • Forces will govern the behaviour of the molecules or particles in
nanostructures
• Give rise both to equilibrium phenomena, like differences in ionic
distribution, or kinetic phenomena, like (macroscopic) viscosity
• In the 1940s, Derjaguin,Verwey, Landau and Overbeek developed the
DLVO theory
• Two major forces acting in the nanometre range between surfaces, namely,
electrostatic forces and van der Waals forces
• Very successful in providing the theoretical framework for observed
behaviour of colloid interaction and stability

34. • Electrostatic forces act as far as the electrical double layer extends, which is
typically from 1 nm to 100 nm
• depending on the electrolyte concentration, and are either repulsive or
attractive
• van der Waals forces predominantly act at distances smaller than 2 nm and
are always attractive
• In 1954, Derjaguin devised a surface forces apparatus (SFA) to measure the
forces acting at nano scale
• Capillary force originates in the adhesion between the liquid and the solid
surface molecules, and the cohesion between the liquid molecules
• Atomic force microscopy (AFM) has recently become the most outstanding
method for measuring surface forces
Cont……

36. • Surface-energy-related phenomena
• Shear-related phenomena
• Electrical double-layer-related phenomena
• Size-related phenomena
• Entropy-related phenomena
• Molecular-structure-related phenomena

37. • Transport Phenomena
• Chemical Analysis
• Study of Gene Expression
• Water Purification

38. Transport Phenomena

39.  Add functionality for sample manipulations in analytical chemistry, such as
sample injections, separation, purifications, and preconcentration for
quantitative and qualitative identification
 NCAMs functioning as controllable molecular
gates can mediate digital transfer of fluid from
one microfluidic channel to another
This capability has consequently found use in a
miniaturized lead sensor that uses DNAzyme and
for preparative post-separationmprocessing for
mass limited samples
Nano Capillary Array Membrane

40. One system to provide all of the
possible required analyses for a given
type of problem
All processing steps are performed on
the “chip”
No user interaction required except for
initialization
High throughput screening (HTS) and
diagnostics are two major applications
for Lab-on-a-chip
Partitioning of functions between
disposable and instrument is very
different for HTS and Molecular
Diagnostics

41. • Nanofluidic system to monitor gene expression continually, a
so-called dynamic study.
• Altering the genes to express fluorescent proteins and exposing
the cells to different conditions
• Measure the effects on gene expression as a change in
fluorescence

42. •Detectability
 concern chemical or physical analysis
 detection will become very problematic when low concentrations are present
together with small detection volumes
•Fouling and stability

43. Thank you…..