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industry
advanced
manufacturing
can also be used to create monodisperse
particles and gels, which are benefi cial
for many health-related diagnostic, drug
encapsulation and industrial production
applications. One of the applications being
used to test the droplet platform being
developed is the manufacture of highly
monodisperse, self-immobilised enzymes.
Microcantilevers
Microcantilevers have captured the
attention of international scientifi c
communities and micro-manufacturing
industries because of their growing
importance in fundamental studies and
numerous applications in various branches
of science and technology development.
Conventional microcantilevers are made
of silicon (Si) and similar hard materials.
Polymers are much softer, offer a wide
range of spring constants and allow
for more deformation than conventional
cantilevers. The micro-manufacturing group,
together with the CSIR National Centre for
Nanostructured Materials are investigating
novel polymer materials and manufacturing
methods to exploit these advantages.
Devices for bacteria detection in water
The consumption of pathogenic bacteria,
such as E.coli, leads to various diarrhoeal
diseases, resulting in approximately three
million deaths annually worldwide. In South
Africa, diarrhoea is the third highest cause
of death among children under the age of
fi ve years (after HIV/Aids and low birth
weight).
inexpensive, POC diagnostic tools to the
market. This is thanks to advantages such
as low fabrication costs, low sample and
reagent volume requirements, and high
portability.
The proposed detection device will be
made of specialised paper materials,
patterned with fl ow channels which,
through capillary movement, guide the
fl ow of the sample to detection zones that
are preloaded with analysis reagents.
These reagents will then give rise to either
fl uorescence or colour changes, providing
a visual indication of the presence
or absence of the targeted bacteria.
Incorporation of electronic readers or
calibration charts, etc., gives these devices
the potential of becoming semi- to fullyquantitative
tests.
Funding and facilities
The Micro-manufacturing group has been
established with funding from the CSIR
and the Technology Innovation Agency
(TIA). A clean room for the manufacture of
microfl uidic moulds has been built, and this
allows for the fast turnaround of designs for
testing. In addition, the clean room is also
used for the manufacture of polymer-based
microcantilevers. Two further laboratories
are available for the testing and assembly
of these devices. These laboratories are
equipped with state-of-the-art microscopes
and other analytical equipment.
Getting to grips
Microfl uidics: Microfl uidics is a multidisciplinary fi eld that deals with the behaviour,
control and manipulation of sub-microlitre fl uid volumes in a constrained space. A
microfl uidic system consists of a series of sub-millimetre channels with micro-sized pumps,
valves, reservoirs and actuators to control the fl uid around a circuit on a microchip. The
fl uid can be anything from a blood sample to a water droplet. The ability to miniaturise
and integrate complex functions, which are normally undertaken in sophisticated
laboratories, holds enormous potential for lab-on-chip devices for the health domain.
Microcantilever: A microcantilever can act as a physical, chemical or biological sensor
by detecting changes in cantilever bending or its vibrational frequency. It can give
qualitative as well as quantitative detection capabilities with high sensitivity, low cost,
low analyte requirement, non-hazardous procedures and quick sampling, as compared
to conventional analytical techniques.
In view of this, the Micro-manufacturing
research group is collaborating with the
CSIR Polymers and Composites research
group to develop a bacterial detection
system which includes bacteria preconcentration
and rapid detection in water.
Paper-based microfl uidics, a new research
direction, has the capability of providing
A typical microfl uidic mould used for the manufacturing of devices.
39 PROJECT HIGHLIGHTS