work. This technology has very prominent advantage with respect to low overall
chip area and high integration density. For handling small volumes of fluid of the
range indicated above various micro-channels and micro-confinements are devised
using a variety of techniques in which the mixing, reacting, handling and
transporting etc. take place. The main motivations of this field are powerful
analytical and diagnostic techniques which have been parallel devised by chemists,
biochemists and material scientists over the last couple of decades to understand the
life processes for sustenance of life itself. These may include modern methods as
used in chemical diagnostics like [ 1 ]:
- Micro-analytical methods (Chemical analysis methods for higher sensitivity and
higher resolution)
(a) High-pressure liquid chromatography (HPLC)
(b) Matrix assisted laser desorption/ionization time of flight methods (MALDI-
TOF)
(c) Capillary electro-osmosis and electrophoresis methods (CE) - Sensitive detection of for chemical and biological hazards which may have
military connotations (being used as bio-warfare tools) - Molecular biology driven methods to recognize basic structures of biological
entities deterministically which may include:
(a) High throughput DNA sequencing
(b) Causative genomics
(c) Protein crystallography and folding
(d) Immunological mechanisms through the study of binding chemistries of
various pathogenic and non-pathogenic biological entities so on so forth
The fluid which is analysed in the microfluidics domain can be handled in
various ways. Hence depending on this, microfluidics is classified in three different
types, continuous flow microfluidics (in which there is continuous flow of fluid
through the micro-channels), droplet based microfluidics (in which discrete manip-
ulating volumes are formed in the immiscible phase) and digital microfluidics
(in which discrete, independently controlled droplets are manipulated in the open
environment i.e., on the substrate) [ 2 ]. Depending upon the requirements, various
materials like silicon, glass and various elastomers (polydimethysiloxane (PDMS),
SU8 (negative photoresist)) are used in microfluidics for making various micro-
channels, micro-valves etc. Hence keeping in view the various requirements of the
field of microfluidics, a large domain of researchers are involved in the field
pertaining to the advanced applications of the field of Microfluidics.
In recent years, microfluidics has been an extensively explored domain owing to
its high applicability to develop low-cost diagnostic devices. Clinical diagnostics is
one of the promising application areas for deployment of such lab-on-chip systems
also better known as point-of-care (POC) systems [ 3 ]. Lab-on-chip technology is
preferred over conventional laboratory lab oriented techniques due to their faster
performance and overall miniaturized size which leads to reduced use of analytes
34 G. Bhatt et al.