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Sugar sensitive Phenylboronic acid-based hydrogels: Towards glucose
analysis in sweatby
HENOK TESFAY
4th year project
Supervisors: Dr. Aoife Morrin,
Dr Larisa Elena Florea Dr. Colm Delaney
School of Chemical Sciences May 2016
1
Aim of the project
• To build implantable glucose sensors that can potentially detect glucose level in our body within a few minute.
2
Source: http://www. idf.org/about-diabetes 3
Diabetes is becoming a big problem in our society, affecting currently one in every 20 people in the world.
Prevalence of Diabetes • Diabetes caused
5.1 million deaths in 2013. Every six seconds a person dies from diabetes.
Source: http://www. idf.org/about-diabetes
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Is there a cure for Diabetes?• No cure for diabetes • Controlling blood glucose levels in
diabetic patients is really important but it is not easy.
• Nowadays, glucose monitoring is performed using devices that measure glucose in blood drops.
• That implicates that all people with diabetes must prick their finger and test drops of blood throughout the day.
Source: http://www.slideshare.net/funk97 / glucose-monitoring-smart-watch
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• While blood test is the most known way of measuring glucose level, other available body fluids are becoming interesting targets for non-invasive glucose measurements. Such as : sweat, saliva and tears .
Source: google contact lens
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Complex between phenylboronic acid (PBA) moiety and a sugar molecule in aqueous solution
PBA bearing hydrogel
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Sugar
Photochemical polymerization(Gel forming reagents)
Acrylamide(AAm)
3-(Acrylamido) phenylboronic acid – (PBA)
sugar reactive monomer
2-Hydroxy-2-methpropiophene-(HMPP)
photo initiator
Methylenebisacrylamide (BIS)
Cross-linker
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20mol%PBA gel in Glucose
• Control
• In 4mM
• In 6mM
• In 10mM
• In 20 mM
20mol%PBA gel in Fructose
• Control
• In 4mM
• In 6mM
• In 10mM
• In 20mM
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20mol%PBA gel in Glucose 20mol%PBA gel in Fructose
Width (µm) Length(µm) Width(µm) Length(µm)
Control 3495.11 1185.65 3495.11 1185.65
4mM 4083.23 1381.65 5321.40 2123.96
6mM 4412.98 19333.18 5547.18 2123.86
10mM 4495.17 1690.87 5680.85 2309.53
20mM 4752.92 2216.65 5763.33 2825.02
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Time dependent swelling of Hydrogel in 10mM Fructose solution (5mol% PBA)
0 10 20 30 40 50 600
0.050.1
0.150.2
0.250.3
0.350.4
0.45
Fructose
Time in hrs
Swel
ling
Ratio
11
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Behaviour of 5mol% PBA Hydrogel in Glucose, Sucrose & Fructose Solutions
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5-0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
GlucoseLinear (Glucose)FructoseLinear (Fructose)SucroseLinear (Sucrose)
Concentartion in mM
Swel
ling
Rat
io
Behaviour of Hydrogel (20mol% PBA) in different concentration of Glucose, Fructose & Sucrose
0 1 2 3 4 5 6-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
GlucoseSucroseFructose
Concentration in mM
swel
ling
Ratio
13
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Linear regression Analysis of Calibration Plots
Sugars R2 (1-5mM) Slope (Swelling ratio/[]
LOD (3σ/M) LOQ(10σ/M)
Fructose 0.9971 0.067 0.30 1.0
Glucose 0.9933 0.026 0.50 1.50
Sucrose 0.8661 0.003 2.20 7.22
0 1 2 3 4 5 6-0.1
0
0.1
0.2
0.3
0.4
GlucoseLinear (Glucose)FructoseLinear (Fructose)SucroseLinear (Sucrose)
Concentartion in mM
Swel
ling
Rat
io
Glucose in 20mol% & 5mol% PBA Hydrogel
0 5 10 15 20 250
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Glucose in 20mole%PBAGlucose in 5mole% PBA
concentration of Glucose in mM
Swel
ling
Ratio
15
Conclusion
• Generally, the hydrogel shown a swelling in response to the Glucose and Fructose. But didn’t show a response to the sucrose.
• We have been particularly interested to create implantable glucose sensors that can potentially detect glucose concentrations within few minutes.
• For the best accurate measurement research being used to develop a Glucose gel sensor based on PBA chemistry to being measured using impedance.
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fixed voltage 20 mV frequency range 0.1 – 10 MHz
Solartron (Impedance)
0 5 10 15 20 25 30 35 40 45 500
1
2
3
4
5
C
(nF)
glucose concentration (mM)
1 kHz
Acrylamide20 mol % PBA1 mol % bisAm1mol % HMPP(1:1) water/DMSO
UV light30 minutes
Electrode Functionalisation with Hydrogel
Glucose Additions
Electrical Impedance Spectroscopy
The electrode was immersed in buffer solution (5mL
each electrical measurement was added 10 microliters of glucose (2.5M).
• an increase of concentration of glucose and increase of capacitance value.
• the change in structure of hydrogel cause changes in dieletric properties of the hydrogel. 18