Journal of Medicine Vol 2 - Amrita Institute of Medical Sciences and ...

Amrita Journal of Medicine
Nanosciences Research at the Health Sciences Campus of Amrita Vishwa Vidyapeetham
velop in the near future. This includes the toxicological
effects of nanomaterials, use of naturally occurring materials
in nanomedicine and the development of
nanostructured materials for solar energy applications.
ACNS will also have a strong academic focus with a
college of nanosciences devoted to the training of the
next generation of Indian nanotechnologists,
nanobiotechnologists and nanomedical scientists. A beginning
to this is the start of a two-year Master of
Technology program in Nanomedical Sciences that is starting
in August 2007 with 30 students admitted each year.
The focus of this Master of Technology program is to
provide a fundamental understanding of nanomaterials
sciences that have applications in the medical sciences
as well as a thorough training in the medical sciences
relevant to current potential applications.
TISSUE ENGINEERING
The coinage “tissue engineering” immediately and
correctly implies a combination of the disciplines of biology
and technology. Modern tissue engineering took
its birth in the late 1980s in Boston, USA, through the
pioneering efforts of Dr. Joseph Vacanti of Boston
Children’s Hospital and Dr. Robert Langer of Massachusetts
Institute of Technology 4 . The basic concept involves
the development of a scaffold into which are introduced
appropriate cells that eventually multiply into the tissuespecific
cells and regenerate the target tissue. The dream
is that this approach can eventually regenerate an entire
organ although that reality is still fairly distant. Much of
the current research in the world is focused on how to
expand the cells in vitro in the scaffold so that one can
generate sufficiently large volumes starting with limited
cells and how to prevent cell death during subsequent
implantation. Since mature cells can only be expanded
to a very limited extent much research is focused on the
use of stem cells, and even here, tissue-specific adult
stem cells may be the choice of the future 4 .
One role of nanotechnology in tissue engineering is
the ability of nanomaterials to more efficiently expand
cells. This has been observed in our labs at the ACNS
where our preliminary observations show more efficient
attachment and proliferation of cells on nanostructured
surfaces 5 . A second role that nanomaterials can play is in
controlling the chemical and mechanical properties of
scaffolds. Nanoparticle reinforcements can effectively
influence the strength as well as the biodegradability of
the scaffold. This property becomes important when implantation
is done before complete tissue regeneration.
In this case, the scaffold must temporarily fulfill the
mechanical functions of the tissue. Further, in many cases
of tissue engineering, the scaffold is designed to be biodegradable
and ideally the degradability is matched so
that degradation is complete when the tissue has fully
regenerated. There is work that shows that nanoparticles
tend to enhance material degradability 6 and can therefore
be used to tune the degradability of scaffolds.
Currently at ACNS we are developing novel methods
to process scaffolds out of many candidate biodegradable
materials, including naturally occurring materials,
such as chitosan. One useful technique, developed in
the 90s in the US is electrospinning 7 , which is capable of
readily generating nanofibrous materials, which have a
strong resemblance in structure to the extracellular matrix
8 . At Amrita we are exploring different ways of
controlling nanostructure and microstructure using
electrospinning 9 .
EARLY DIAGNOSTICS AND DRUG
DELIVERY
An exciting discovery that propelled the field of
nanobiotechnology is that material particles in the
nanosize regime have strong interactions with other biological
nanomaterials, such as, protein, DNA, enzymes,
antigens, antibodies and cellular receptors, allowing them
to be used as highly efficient biological probes 10 . A particularly
attractive choice is a semiconductor nanoparticle
in the size regime under 10 nm. Such particles, termed
quantum dots, exhibit luminescence of wavelength that
is strongly particle size dependent and hence are perfectly
suited for diagnostic imaging of specific cells. The Department
of Biotechnology, Government of India is
supporting a project at ACNS for the development of targeted
quantum dots for early detection of oral cancer.
The approach we are taking is to biofunctionalize quantum
dots with antibodies targeted to known cancer
biomarkers either in tumor cells or, more interestingly,
in what are known as cancer stem cells – rare pre-cancerous
cells with indefinite potential for self-renewal 11 .
NANOSURFACE BIOENGINEERING
The most well recognized property of the nanoscale
is its extremely high surface activity. Indeed a rough
calculation will show that at a particle size of about 2
nm 100% of the atoms reside on the surface, and therefore
every single atom is capable of reacting with the
environment. If this environment is biological, such as,
when there are protein molecules or cells with nanoscale
receptors on the surface, there is the potential for an unusually
strong interaction of the material with the
biological environment. Using this principle, at Amrita
we have been taking conventional implant materials like
Ti and providing nanoscale features on the surface by
various methodologies such as, laser treatments,
nanochemistry and electrochemistry to provide surfaces
ranging from the nanoscale to the microscale and then
studying the cell-surface interactions 5 .
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