A Colloquium presentation on the emerging field of Microfluidics and it's engineering and social applications in the field of affordable healthcare.

1. Angshuman Pal
B. Mechanical E. – IV (A-2-2)
001411201048
Jadavpur University
STUDY OF MICROFLUIDICS AND ITS
APPLICATION IN BIOMEDICAL DIAGNOSTIC
DEVICES

2. Contents
 Introduction
 The Science of Microfluidics
 Biomedical Diagnostics
 Utility of Microfluidics in Diagnostics
 Methods of Fabrication
 Microfluidics based Diagnostic Devices
 Commercial Considerations
 Conclusion
 References

3. Introduction
 Microfluidics is the study of properties and control of
behaviour of fluids when confined to a small
geometrical region which is typically less than 1mm
in dimension.
 Domain restricted fluid behaviours are significantly
modified due to surface tension, viscous resistance
and material properties in a microscale.
 Governing principles of macro scale liquids are not
valid over micro domains.
 Microfluidic phenomena can be continuous flow,
droplet based, or digital based.
 Recent research has shown the potential for
application of microfluidic principles in different
categories of engineering devices, including a range
of biomedical diagnostic devices.

4. The Science of Microfluidics
 Microfluidics is typically characterised by the
following:
 Small volume
 Small size
 Low power consumption
 Continuous flow microfluidics deals with steady or
unsteady dynamics of the motion of liquid in some
microchannel.
 Droplet based microfluidics is concerned about
mixing, encapsulation, sorting, and sensing of liquid
droplets of microscale volume.
 Digital microfluidics is an open channel phenomenon
where discrete microscale droplets of liquid are

5. Biomedical Diagnostics
 Life expectancy of human beings has increased
significantly throughout the globe, creating
necessity for advanced and accessible
healthcare.
 Medical diagnosis is the process of determining
which disease or condition explains a person's
symptoms and signs.
 Diagnostics also involves checking and
monitoring vital body parameters which are an
indication of a person’s state of health.
 Ease of procurement, facility in performing the
test, low cost and high accuracy are the basic
requirements.

6. Utility of Microfluidics
 Micro scale liquid transport is not a novel
phenomenon in biological organisms including
human body tissues and channels. This endows
the following advantages:
 Accurate reproduction of natural features.
 Superior flow control
 Protection against contamination and leakage.
 A variety of human, animal, plant and natural inert
phenomenon are occurring on a micro domain
which follow the principles and laws of
Microfluidics.

7. Methods of Fabrication
 Fabrication of microscale devices of high
accuracy and precision remains a challenge.
 The following three methods are the most popular
among microfabrication techniques:
 Photolithography
 Soft lithography
 Rapid Prototyping
 With smaller dimensions and fluid flow domain,
the challenges of maintaining dimensional
accuracy and predicting the liquid behaviour
precisely increase considerably.

8. Microfluidics based Diagnostic
Devices: Paper based
 Paper is easily available and cheap material is composed
of an enormous matrix of cellulose fibres which form a
network of capillaries.
 By introducing hydrophobic barriers on the paper surface,
direction and flow of liquid through the microcapillaries
within the paper matrix may be controlled.
 External actuation mechanism like surface acoustic waves
(SAW), centrifugal forces, electrokinetic forces etc are
used in conjunction to capillary forces.
 Separation of liquids and diagnosis by observation of
flow rate can be achieved using paper based devices.
 Colourimetric detection of contaminants and foreign
particles in body fluids like blood is possible. Graphite tips
of pencils are now being used as electrodes to enhance
flow rate under externally applied potential.

9. Microfluidics based Diagnostic
Devices: CD based
 Microfluidic functions like mixing, valving,
separation, bubble formations etc have been
successfully demonstrated on ordinary Compact
Disc based devices.
 Microchannels are engraved between adhesive
layers of polymers like poly-Methyl Meta Acrylate
(PMMA). Fluid is guided through the channels by
centrifugal action or by syringe pump
mechanisms.
 The response of body fluids like blood and the
separation of its constituents are possible
methods of haemoglobin testing and RBC
count testing.

10. Microfluidics based Diagnostic
Devices: Thread based
 Thread based devices are a new discovery in the
horizon and are still in the prototyping phase.
 Cheap material like cotton yarn or wool can be
used for purposes like liquid mixing through
diffusion and acid-base titration.
 External influence of electric fields or other
fluidic forces are used to enhance the transport of
liquid through natural fabric material.

11. Commercial Considerations
 High demand: Demand for point-of-care diagnostic
devices is independent of factors such as market
conditions and fluctuation in income of consumers.
 Low cost: Affordable healthcare remains the biggest
concern for governments and international humanitarian
organizations. Paper or CD based diagnostic devices have
negligible material and manufacturing costs and hence are
assured of commercial success.
 Ease of Manufacturing: Microfluidic platforms are
essentially built on everyday objects available readily
around us. Manufacturing costs of such devices are
considerably low at optimized industry-friendly designs.
 Environment friendly: Microfluidics based devices are
single use and easily disposable.
 Simple Method of Use: With simplicity in functioning,

12. Conclusion
 In an environment where demand for easy
portable point-of-care diagnostics is constantly
on the rise, Microfluidic devices provides a very
welcome path to effective solutions for biomedical
engineering problems.
 Being a multidisciplinary field, Microfluidics is
capable of providing customized solutions to
problems being faced by the healthcare industry,
all at an affordable cost.
 It is expected that with more advanced research
going into microfluidics, simple yet highly
effective prototypes of diagnostic devices will be
developed so that a major chunk of pathological
tests and diagnosis may be carried out using this

13. References
 Kar, Shantimoy, Tapas Kumar Maiti, and Suman
Chakraborty. "Microfluidics-based Low-Cost Medical
Diagnostic Devices: Some Recent Developments."
INAE Letters 1.2 (2016): 59-64.
 Martinez, Andres W., et al. "Diagnostics for the
developing world: microfluidic paper-based analytical
devices." (2009): 3-10.
 Chakraborty, Debapriya, and Suman Chakraborty.
"Controlled microbubble generation on a compact
disk." Applied Physics Letters 97.23 (2010): 234103.
 Dey, Ranabir, et al. "Ultra-low-cost ‘paper-and-
pencil’device for electrically controlled micromixing of
analytes." Microfluidics and Nanofluidics 19.2 (2015):
375-383.
 https://en.wikipedia.org/wiki/Microfluidics