Chemistry Reference
In-Depth Information
has been known to be
. However, today 80 % of people
with diabetes live in low- and middle-income countries, and the socially disad-
vantaged in any country are the most vulnerable to the disease. The number of
people with diabetes is rapidly increasing in the Middle East, Western Paci
'
a disease of the wealthy
'
c,
sub-Saharan Africa and South-East Asia, where economic development has trans-
formed lifestyles. These rapid transitions have resulted in high rates of obesity and
diabetes; developing countries are facing a healthcare challenge coupled with
inadequate resources to protect their population. According to International
Diabetes Federation, in sub-Saharan Africa, where resources lack and governments
may not prioritise screening for diabetes, this proportion is as high as 90 % in some
countries [
5
]. The new estimates show an increasing trend towards younger people
developing diabetes [
5
]. The
financial burden of diabetes is annually 548 billion
dollars, which is 11 % of the global healthcare expenditure [
5
]. Yet, it is estimated
that 175 million people are undiagnosed today [
5
]. This is because there are few
symptoms during the early years of type 2 diabetes, or those symptoms are not
recognised as being related to diabetes. Type 2 diabetes can go unnoticed and
undiagnosed for years. In such cases, those affected are unaware of the long-term
damage being caused by diabetes.
Diabetes can be screened with blood glucose meters and urine strip tests. These
tests are low cost, but considering that 1 billion people live on less than $1.25 a day,
they are not affordable [
6
]. For example, glucometers ($40), a lancing device ($15),
lancets (10
$100 for testing hundred people
in a developing world country. On the other hand, the urine dipstick test, which
costs about 50
¢
) and test strips (50
¢
) can cost up to
*
, has low sensitivity and often provides erroneous results due to
subjective reading. The development of diagnostic devices that are low cost,
reusable, user friendly, non-invasive and reliable will help deprived communities.
Once diagnosed, the management of diabetes becomes a liability for diabetics. Most
diabetics exhibit hypo/hyperglycemia requiring tight control of blood glucose
concentration. In diabetes management, diabetics need to regularly measure their
blood glucose by
¢
five times a day to control the concentration
of glucose in blood, which requires at least three insulin injections daily. This
invasive practice reduces the rate of patient compliance and results in less effective
glycaemic control. In particular, young adults have lower compliance as compared
to older patients in providing samples to healthcare workers and self-managing their
diabetes. Measuring the concentration of glucose in urine is a less accurate way of
estimating the concentration of glucose in blood since urine tested is produced
several hours before the test. Currently, there is an ever-increasing need for low-
cost sensors to non-invasively manage diabetes. An ideal glucose sensor should
operate under physiological pH, ionic strength (IS) and in the presence of biological
fl
finger pricking up to
fluids, and measure glucose concentrations with high accuracy both within and
outside the normal blood glucose concentration range (4.2
6.7 mM) [
7
] with a
quick turnaround time (<5 min). Development of non-invasive and accurate diag-
nostics that are easily manufactured, robust, and reusable will provide monitoring
high-risk individuals in any clinical or point-of-care environment, particularly in the
developing world.
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