Lactate Sensor Design:
Smart Gels for Diabetes Pre-screening
Toby Li, Wern Ong, Joseph Sun, Stephanie Wu & Christine Zhang
Advisors: Franz Baudenbacher, Ph.D. & Paul King, Ph.D
Methods
• Hygienic, fast-acting, non-invasive, disposable, uniform, and cheap lactate sensor
• Measurement of volumetric change by Q ratio shows reaction of hydrogel polymer
to various lactate concentrations
• Hydrogel polymer sensitive to lactate concentrations in the 0.2-0.5 mmol range
• Proof of concept for future lactate sensor design
Height Change
31
250
16
Volume (mm^3)
200
150
100
50
29
28
27
26
Batch 1 (Normal)
25
Batch 2 (DMAEMA)
24
23
0
Prediabetics
(U.S.)
World Wide
Ethnicity
Weight
Family History
Other Symptoms
22
World Wide
(2025)
Heart Disease/Stroke
1
2
Sample
Amputation
Background
Batch 4
8
Batch 5
6
4
160
400
120
100
80
y = 8.7356x + 31.964
R² = 0.9648
60
40
20
Lactate [0.3]
2
4
6
8
10
Lactate Concentration (mM)
y = 25.966x + 97.288
R² = 0.9796
350
250
200
y = 23.687x + 51.436
R² = 0.9812
150
100
50
12
0
2
4
6
8
10
12
Lactate Concentration (mM)
8
Number Tubes
74
Gel Costs
$2.67
LOD costs
$17.48
Total Costs
$21.11
Cost per Tube $0.29
6
4
2
0
2
4
6
8
10
12
[Blood Lactate]
Figure 2. Shows the correlation of saliva
lactate levels to lactate levels in the
blood3.
Figure 3. Correlates lactate levels in the
blood to the probability of developing
type-II diabetes2.
Smart Gel
Lactate Sensor
Plasma Glucose
Blood Glucose
Saliva Lactate
Low Cost
Expensive
Complaints
Nausea
Fasting + 4 hrs
Low Cost: $0.29
Lab Setting
Self Testing
Accurate Results
Varied Results
Figure 9. Financial analysis
of the cost of production
including material costs.
Draw Blood
6 weeks
12-14 hrs Fasting
Lab/Home Setting
Lab Setting
May not identify
pre-diabetes
Non-invasive
2.5 hrs
Future Considerations
300
Figure 7 & 8. Measurement of volumetric change by beans of Q ratio after 2.5 and 24 hours of exposure
show the hydrogel polymer’s reactivity and sensitivity to different lactate concentrations.
10
Oral Glucose
Tolerance Test
Needle Prick
Varied Results
0
0
12
Glycated
Hemoglobin
$20-$30
Fasting Plasma
Glucose Test
Hydrogel Reaction to Lactate at 24 Hrs
y = 9.9336x + 51.468
R² = 0.9716
140
Lactate [0.2]
Figure 6. Hydrogels of different lactate oxidase
configurations and their response to different
solutions using Design 1.
Hydrogel Reaction to Lactate at 2.5 Hrs
0
Blood and Saliva Lactate Correlation
10
Acetic Acid
Figure 5. Shows the response of different hydrogel
configurations to an acidic solution.
Blindness
Nervous System Disease
A1C Test
12
0
High Blood Pressure
Kidney Disease
14
2
Percent Weight Increase
U.S.
Height Change (mm)
30
Percent Weight Increase
Prevelance (millions of people)
pH Response
300
Complications:
Risk Factors:
Conclusion
Diabetes
Age
0
Mix hydrogel ingredients together using proper volumetric ratios
Dry overnight in oven and then soak hydrogel polymer in deionized water
Measure un-stimulated wet weight
Soak hydrogel with lactate solution
Measure stimulated wet weight and calculate Q ratio (stimulated/un-stimulated)
Figure 4. Different design approaches. Design 1 utilizes the direct volumetric change caused by
swelling. The volumetric change caused by directional swelling is extremely small and difficult to
measure. Design 2 amplifies the change in volume for more accurate and sensitive readouts.
Results
Figure 1. Prevalence of diabetes in the population.
[Saliva Lactate]
•
•
•
•
•
Figure 10. Shows the inputs and outputs of the hydrogel lactate sensor system.
Diabetes
Diabetes:
• Chronic illness
• Characterized by high
blood sugar
• Caused by insufficient
insulin levels
• Body has become resistant
to insulin
• Medical expenditure of
diabetics is 2.3x higher
than non-diabetics
Methods
Design 2
Purpose
• Design and develop a diabetes pre-screening device to fill market void
Background
• Cost of diabetes (direct/indirect) per person = $11,744 per year
• Cost of diabetes over lifetime (33 yrs) = $387,552 per person4
• Cheap, non-invasive, accurate, and easy to use device is needed for large scale prescreening and diabetes prevention
Solution
• Develop hydrogel based lactate sensor that is sensitive to saliva lactate levels
• Volumetric change (swelling) of hydrogel polymer caused by saliva lactate
concentration is correlated to blood lactate levels
• Correlation of lactate concentration to development of type-II diabetes
• If test is positive, patients can take steps to prevent development of the disease
including changes to diet and exercise
Design 1
Introduction
Polymer
HEMA
DMAEMA
TEGDMA
EG
Water
Ammonium Persulfate
Sodium Bisulfite
Total
Cost ($)
0.33
1.80
0.10
0.42
0.00
0.02
0.01
2.67
• Use of more sophisticated fabrication techniques including the use of sonication in
order to produce more sensitive polymer and more accurate readouts
• Introduction of a colorimetric assay as a means of internal control
• Incorporate digital readout for easy to read and accurate readouts
• Establishing testing protocols for use of this device in public health settings
References
1. Traitel, Tamar. "Characterization of Glucose-sensitive Insulin Release Systems in Simulated
in Vivo Conditions." Biomaterials (2000): 1679-687. Print.
2. Segura, R. "A New Approach to the Assessment of Anaerobic Metabolism: Measurement
of Lactate in Saliva." Journal of Sports Medicine (1996): 305-309. Print.
3. Crawford, Stephen O. "Association of Blood Lactate with Type 2 Diabetes: the
Ahterosclerosis Risk in Communities Carotid MRI Study." International Journal of
Epidemiology (2010): 1647-655. Print.
4. American Diabetes Association. "Economic Costs of Diabetes in the U.S. in
2007." Diabetes Care (2008): 596-615. Print.