Topics Covered
About Diabetes
Nanomedicine
Applications of
Nanotechnology for Diabetes Management
Oral Insulin
Monitoring
Glucose Levels
Potential Long-Term
Treatments or Cures for Diabetes
Nanoporous
Immunoisolation Devices
Artificial Pancreas
Conclusion
References
About Diabetes
Diabetes (diabetes mellitus) is a metabolic disorder which results
in high levels of blood glucose. It can be classified as either Type 1
or Type 2, depending on the reason for the high glucose levels. Type 1
diabetes means that the pancreas cannot produce insulin (a hormone
which enables the uptake of glucose by the liver, muscle and fat
tissue), whereas Type 2 means that the body's cells do not respond to
the presence of insulin.
Whilst Type 1 diabetes can be fatal if untreated, most patients
today survive into old age - however, they must inject insulin several
times a day to allow their body to use the glucose from their food.
Our understanding and ability to treat insulin has been improving
steadily, ever since the first insulin injections were carried out in
the early 1920s by Banting and Best. Despite all the advances which
have been made, insulin cannot be cured altogether, and a good deal of
research effort is aimed at improving quality of life for diabetic
patients, making their glucose tests and insulin injections as easy and
non-invasive as possible, and potentially devising a permanent cure for
diabetes.
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Figure 1. A sample of insulin for treatment of
Type 1 diabetes. Image credit: FDA.gov.
Nanomedicine
Nanotechnology holds a great deal of promise for the world of
medicine. It is likely that some of the first truly revolutionary
changes noticeable in our everyday lives will be brought about by
nanomedicine.
the possibilities of nanomedicine include nanoformulations for
efficient drug delivery, smart drugs which only activate when needed,
engineered microbes which produce human hormones, and even
"nanorobots", which would move autonomously around the body acting as a
boost, or a replacement, for our immune system, red blood cells, or
many other biological systems.
Whilst many of these applications of nanotechnology as a long way
off, there is a great deal of active research into medical technology -
much of which is is not very far-fetched. This article explores the
way in which nanotechnology could be used to effectively treat, and
possibly cure, diabetes - in particular Type 1 diabetes.
Applications of
Nanotechnology for Diabetes Management
Oral Insulin
Insulin for Type 1 diabetes is currently delivered by injection, as
orally administered insulin has limited effectiveness. It is denatured
by the acidity of the stomach, and its large size means it is absorbed
slowly, which means it can even be partially digested by enzymes in the
intestine before it can be absorbed into the body.
It has been found that nanoparticles of chitosan (a derivative of
chitin, a natural structural polymer found in crustaceans and fungi),
can be used as a carrier for oral insulin. It protects the insulin from
digestive juices, and allows the insulin to be absorbed into the
bloodstream much more effectively.
Chitosan nanoparticles are cheap and easy to produce, and completely
biocompatible, so this technology should be realized on a fairly short
timescale.
Monitoring Glucose Levels
Current methods of blood glucose monitoring are invasive and often
painful. The finger-prick test has been associated with non-adherence
to treatment regimes by diabetic patients because of this, but it also
has very limited accuracy - it cannot be performed during other
activities, such as driving, or sleeping, and its intermittent nature
means that it can miss important and potentially dangerous spikes and
fluctuations in blood glucose levels in between tests.
Several improved methods for non-invasive, continuous monitoring of
blood glucose have been proposed in the last few years. Many of these
take advantage of the advances in medical technology made possible by
nanotechnology.
Nanosensors could use carbon nanotube electrodes to selectively
measure glucose concentrations. Functionalization or the nanotubes
would allow the presence of glucose to alter the current flowing down
the conductive nanotubes. This data could then be fed to an embedded
microchip, which could send the data wirelessly to a wearable computer.
This would allow accurate, continuous monitoring of blood glucose
levels. However, there may be issues with ensuring the biocompatibility
of the sensors, as they would need to remain implanted in the body for
a long period of time.
One of the most promising near-term technologies is a "smart
tattoo", which would contain polymer nanoparticles coated with
molecules which fluoresce when glucose drops to dangerous levels,
creating a visible glow in the skin. Whilst this is clearly not a
complete monitoring solution, it would be helpful in identifying danger
between tests.
.jpg)
Figure 2. The "pin-prick" glucose test
could be replaced with more accurate and convenient methods using
nanotechnology. Image credit: CT.gov
Potential
Long-Term Treatments or Cures for Diabetes
Nanoporous
Immunoisolation Devices
Pancreas transplants, which could potentially cure Type 1 diabetes,
are extremely risky procedures. Even a partial transplant, targeting
only the Islets of Langerhans cells which produce insulin, result in a
massive immune response, rejecting the new organ. The amount of
immunosuppressant drugs required to prevent rejection is unsafe, and
may actually damage the islets of Langerhans cells themselves.
One potential solution to this is to provide a "safe harbour", where
transplanted pancreas cells are unaffected by the immune system whilst
remaining productive. This could be achieved by using a porous
container made of silica, or some other inert material. If the pore
size of the material was around 20 nm, human or animal islets of
Langerhans cells within would remain accessible to smaller molecules
such as glucose and insulin, but white blood cells and other immune
system components would be unable to access them, therefore preventing
rejection.
Artificial Pancreas
The artificial pancreas is a machine which would monitor blood
glucose levels using an array of sensors, and release insulin from a
reservoir into the bloodstream, using an infusion pump, whenever it is
required. The concept has been around for some time - the first
proposal for an artificial pancreas was made in 1974.
With the technology at that time, and even the technology available
currently, however, the size of such a device would make it impractical
for permanent use.
The advances made possible by nanotechnology could change this -
simple nanomachines which respond directly to glucose concentration to
release insulin as it is needed, without the need for a controlling
computer unit, could potentially act as a one-time treatment which
would remove all symptoms of diabetes permanently.
Conclusion
In the long run, nanotechnology will clearly open up many routes to
treatments and cures for diabetes, as it will for many of the diseases
and conditions that currently plague mankind. Whilst some of these
technologies are quite far-fetched, there is evidence that we will see
significant advances in the treatment and management of diabetes quite
soon.
References
- "Nanotechnology and Diabetes", K. Martinac and Ž. Metelko,
Diabetologia Croatica, 2005
- "Applications of Nanotechnology in Diabetes", Arya et al,
Digest Journal of Nanomaterials and Biostructures, 2008
- "Recent Trends in Diabetes Treatment Using Nanotechnology",
Subramani et al, Digest Journal of Nanomaterials and Biostructures, 2012
- "Nanotechnology and the Future of Diabetes Management",
Meetoo and Lappin, Journal of Diabetes Nursing, 2009