IEEE Consumer Electronics Magazine - January/February 2020 - 37

Stimulated Emission of Radiation) makes the
setup costly and bulky. An enzyme sensor has
been explored for glucose measurement in
saliva.14 Glucose detection is possible using
Intensity Modulated Photocurrent Spectroscopy
that connects the electrodes to the skin, which
is affected by sweat.15 High precision level is not
possible through these methods as sweat and
saliva properties vary for individuals. The blood
glucose measurement has also been explored
using Raman spectroscopy but it is not portable.16 Glucose measurement is possible from an
anterior chamber of the eye, which limits its
usage of continuous monitoring.17 Blood glucose
has been estimated using photoplethysmography (PPG) signals.18; 19
PPG signal analysis is not based on the principle of glucose molecule detection. Therefore,
specific wavelengths are not required for glucose estimation, but accuracy is an issue. iGLU
is more precise compared to the PPG based system for glucose measurement. In this way, long
NIR (Near Infrared) waves for optical detection
has been considered for glucose measurement,
which is not a comparatively precise glucose
measurement system, as long wave has shallow
penetration.20 Therefore, small NIR wave is preferred for glucose detection (see Figure 3).
Prior approaches in glucose monitoring
include both wearable and nonwearable. Raman
spectroscopy, photoacoustic spectroscopy,
and invasive approach based systems are not
wearable. Minimally invasive devices, which
have been discussed, are implantable. Other
approaches based on noninvasive devices are
wearable. Here, iGLU is a noninvasive, optical
detection based wearable device for CGM with
IoMT framework.

Consumer Electronics for Glucose Monitoring
Several devices have been developed for noninvasive blood glucose measurement. Some
products such as glucotrack, glutrac, glucowise,
DiaMon Tech, and devices from CNOGA medical
are not commercialized. Glutrac is a multiparameter health test device with smart healthcare.
However, they have limitations in terms of
precise measurement. The cost of the product
is also high, which is in the range of $300 to
$400 USD.

January/February 2020

Figure 3. PPG signal versus NIRS based glucose estimation.

A NOVEL WEARABLE FOR
CONTINOUS BLOOD GLUCOSE
MONITORING - iGLU
Non-invasive measurement reduces the possibility of blood-related diseases. However, the
existing approaches have limitations such as
large setup, measuring object, and skin properties (including dielectric constant and sweat
level). Therefore, portable noninvasive precise
glucose measurement devices for continuous
monitoring are needed.21
The following questions are resolved in
iGLU for the advancement of smart healthcare:
1) How can we have a device that automatically performs all the tasks of blood-glucose
monitoring at the user end without internet
connectivity, and stores the data in the cloud
for future use? 2) Can we have a device that
can perform automatically to avoid hassle and
risky finger pricking all the time monitoring is
needed?
The "Intelligent Glucose Meter" (i.e., iGLU)
performs noninvasive, precise, painless, lowcost CGM at the user-end, and stores the data on
cloud in an IoMT framework (See Figure 4). The
contributions of this article to smart healthcare
include the following:
1) A novel accurate noninvasive glucometer that
uses short NIR waves with absorption and
reflectance of light using specific wavelengths
(940 and 1,300 nm) has been introduced. The
wavelengths are judiciously selected after
experimental analysis.
2) A novel accurate ML-based method for glucose sensor calibration has been presented
with calibrated and validated healthy, prediabetic, and diabetic samples.
3) The proposed noninvasive device has been
integrated in IoMT framework with cloud
access by both the patient and doctor for

IEEE Consumer Electronics Magazine - January/February 2020

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