Touch Based Sensors for Diabetes

Remember the time when you used to have analog clocks in houses and the miniature versions of the same on your wrist. Well, those were the days when even the apple couldn’t keep your doctor away. Confused? I’ll be more clear and elaborate.

Few years ago, the medical algorithms were completely theoretical and much mechanical than ever. However, with the advent of time, everything became more virtual and sophisticated, even the medical procedures and the algorithm involved in them. You no longer have to visit a doctor or even lift up a sphygmomanometer to measure your blood pressure. Just lift your arm and twist the wrist, the digital watch in your hand will calculate the rest. While its not new to measure blood saturation level, pulse rate and blood pressure with a smart watch, blood glucose calculation is yet out of its reach.

Abstract

Diabetes is a medical condition of increased blood glucose level, generally diagnosed by the symptoms of frequent urination, weight loss, glycosuria (presence of glucose in urine), polydipsia (feeling of thirst), etc. The diagnosis of the same has remained to be quite mechanical involving the use of prick needles. A diabetic patient is generally bound to frequently check his/hers blood glucose levels and monitor the same. The monitoring requires the patient to prick their finger by the needle and further check their blood glucose level. While the pricking is clinically safe, its quite painful for the patient.

However, with the advancement in technology and its collaboration with medical science and research, scientists have paved a new path by discovering a sweat based sensor that could detect the blood glucose. While, the technology seems very advanced and definitely less painful; it has yet not been claimed to be completely scientific and accurate in calculating the glucose levels. The lack of precision is widely contributed to the fact that glucose in sweat is affected by a number of external factors, unlike glucose in blood, which will be discussed later in this article.

Conclusively, while the research and development of such a device will be a boon to diabetic patients, it needs to be thoroughly analysed for its efficiency and accuracy. Also, a large scale validation must be employed to this research for better authenticity.

History of Diabetes:

The first known mention of symptoms of diabetes dates back to 1552 B.C., when Hesy-Ra, an Egyptian physician, documented frequent urination as a symptom of a disease that also caused emaciation (extreme weight loss and unnatural thinness caused due to loss of subcutaneous fat). Also, ancient healers around the same time noted that ants seemed to be attracted to the urine of people who had this disease.

In 150 AD, the Greek physician Arateus described the disease as “The melting down of flesh and limbs into urine.” From then on, physicians began to gain a better understanding about diabetes.

Centuries later, people known as “water tasters“ diagnosed diabetes by tasting the urine of people suspected to have it. If the urine tasted sweet, the patient was said to be diabetic. To acknowledge this feature, in 1675 the word “mellitus,” meaning honey, was added after the name “diabetes,” which means siphon. It wasn’t until the 1800s that scientists developed chemical tests to detect the presence of sugar in the urine.

Ways to test blood sugar:

Since ages, testing blood sugar level in a diabetic patient has been a painful procedure. The use of pricking needles for extracting blood sample is not really pleasing to the majority. The procedure involves a device known as Glucometer, which comprises a glucose level detecting electronic meter alongwith a needle specifically called as lancet and a glucose strip.

Working of Diabetes test strips:

When blood is placed onto the one end of the test strip, it reacts with an enzyme called glucose oxidase, producing gluconic acid from the glucose in the blood. At the other end of the test strip, the meter transfers a current to the strip. Basically, the test strip has electric terminals which allow the meters to measure the current between the terminals. The current between the terminals changes depending on the level of gluconic acids that has been produced by the reaction between glucose oxidase and blood glucose. The glucometer then uses an algorithm to work out the blood glucose level based upon the difference in current.

The prick free glucose testing:

With the advent of technology, new and convenient diagnostic methods are arising which are less mechanical and definitely less painful. One such investigational touch based test measures blood sugar in sweat and subsequently applies a personalised algorithm that correlates it with glucose in blood.

Fingers contain many sweat glands and produce a high amount of sweat. The sweat has been clinically diagnosed to contain some amount of glucose. In this sensor based diagnosis, a sweat absorbing polyvinyl alcohol hydrogel sits on a flexible plastic strip. When the patient places the finger on the sensor for 1 minute, the hydrogel component of the sensor absorbs tiny amount of sweats and thereby undergoes an enzymatic reaction that results in a small electrical current, which is detected by a hand held device.

Researchers with the data from standard finger-prick test developed a personalised algorithm which would translate each individual’s sweat glucose to their blood glucose levels. This test was found to be accurate by 95% in predicting blood glucose levels before and after meals. To calibrate the device, a person with diabetes would need a finger prick just once or twice per month.

The glucose in sweat, however, is less than that found in the blood. Stating this fact, proceeds us to the limitations or scientific barriers that are being faced by the researchers for the concerned topic.

Limitations to the touch sensor:

• Since a person’s sweat rate and skin properties may vary, this method is not appropriate to be called universal, as it won’t reflect the accurate value of glucose in blood. So we need a large scale validation to make the reference values more obvious and precise.
• The blood glucose is generally more as compared to the amount of glucose found in sweat. The difference, however is not a specific value and thus, cannot be used to calculate and compare the glucose levels in blood and sweat.
• Temperature and pH changes may also affect the biosensor response and accuracy, because these physiological changes can degrade the enzyme involved in the reaction. Sweat evaporation may also interfere with the results.
• Contamination free skin surface is essential for accurate result. The interference of things like soap from hand-washing, lotions, dirt and food residue need to be researched and analysed throughly by the scientists.

Take your call!!

Technology has always been a boon in health sector and medical advancements. This new sensor based diagnostic method is yet another achievement, which still cannot be celebrated. While the method is obviously less painful from the standard finger prick procedure, it still needs to be analysed and regulated for its accuracy and future application. Such kind of research must gain a boost to open the doors of innovation for young minds.

References:

• Personalized sweat sensor reliably monitors blood glucose without finger pricks
• Potential Blood Sugar Test Uses Sweat, Not Blood

Also Read: “Jamun: The Natural cure for Diabetes”