Download A Novel Approach to Lactate Sensing

Novel Approach to Lactate Sensing
Diabetes Pre-screening Tool
Christine Zhang, Stephanie Wu, Joseph Sun, Wern Ong,
Toby Li
Problem Statement
 No Type II Diabetes Pre-screening device
exists in the market
 To address this need, we will create a
hydrogel based lactate sensor where
lactate level predicts probability of
Diabetes II onset
Diabetes
 Chronic illness characterized by high blood sugar
 Type II diabetes is caused by insufficient insulin levels,
most often because the body has become resistant to
insulin
 Insulin is a hormone produced by the pancreas to
control blood sugar
Indicators/Complications

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Age
Ethnicity
Weight
Family History
Other Symptoms
 Infections
 Vision
 Slow to heal



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
Heart Disease/Stroke
High Blood Pressure
Blindness
Kidney Disease
Nervous System Disease
(Neuropathy)
 Amputation
Current Testing Methods
 3 pre-diabetes tests
A1C
 A1C test
 Fasting plasma glucose test
 Oral glucose tolerance test
 Lactate Sensor
 Simple
 More accessible
Diabetes
Testing
Oral
Glucose
Tolerance
(OGTT)
Fasting
Plasma
Glucose
(FPG)
Diabetes (I & II)
 Prevalence
 25.8 million people (8.3%) U.S. population
 18.8 million people diagnosed
 7.0 million people undiagnosed


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170 million people worldwide
79 million Pre-diabetes (U.S.)
1.9 million cases of diabetes diagnosed in 2010 (U.S.)
300 million people by year 2025
Market Potential
 174 Billion: Total Costs of Diagnosed Diabetes
(2007)
 116 Billion: Direct Medical Costs
 58 Billion: Indirect Costs
 Medical expenditure of diabetics 2.3X higher
than non-diabetics
Performance Criteria
 Sense over a large range
of lactate levels
 0.15 – 0.3 mmol
 Work in a timely manner
 <24 hrs.
 FPG  32 hrs
 OGTT  10 hrs
 Low cost
 < $1 dollar
 Glucose Monitors  $10
 Roche diagnostics  $190
 Accuracy
 60%
Primary Objective
 Develop lactate sensitive screening device for prediabetes screening
 Using lactate sensitive hydrogels
 Measure volumetric change (directional swelling)
 Correlate volume change to saliva lactate Levels
 Predict probability of developing type II diabetes
Solution Description
 Tube filled with lactate sensitive hydrogel polymer
 Exposure to saliva lactate causes directional swelling
of hydrogel polymer
 Volumetric change to saliva lactate concentration
correlated to blood lactate levels
 Correlation of lactate concentration to development
of type-2 diabetes
Volume
Change
Hydrogel
Supporting Figures
Blood and Saliva Lactate
Correlation
12
y = 0.8508x + 0.4099
R² = 0.9572
10
[Saliva Lactate]
Probability curve
8
6
4
2
0
0
2
4
6
[Blood Lactate]
8
10
12
Goals

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Hygienic
Non-Invasive
Disposable
Uniform
Cheap < $10
Easy To Use
Accurate
Factors

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Polymer Ratio (More DMAEMA = more pH sensitive)
Number of Tubes per batch
Concentration of Lactate Oxidase
[Lactate]
Capillary diameter
System and Environment
Temperature
Self Testing
Clinical
Setting
Lactate Conc.
Saliva
Sample
Water
pH
Proteins
Lactate
Sensor
Volumetric
Change
Diabetes
Prediction
Lifestyle
Change
Blood Test
See Physician
Experiment Block Diagram
Literature
Research
Calculation of
Calibration Curve
Hydrogel
Synthesis
Lactate Sensitive
Prototype
Testing Sensitivity
to Lactate
Statistics/Analysis
Establishment of
real world
protocols
Application
Testing
Performance
pH
31
30
Volume (mm^3)
29
28
27
26
Batch 1 (Normal)
25
Batch 2 (DMAEMA)
24
23
22
1
2
Sample
Performance (Cont.)
Batch 7
2
1.8
Height Change (mm)
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
0.2
0.3
0.4
Lactate Conc. [mmol]
0.5
1
5
Conclusion
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Hygienic
Non-Invasive
Disposable
Uniform
Cheap $0.23/tube
Informal Observations
 Hard to measure volume change
 Hard to control directional swelling
 Hydrogel polymer not very sensitive to small lactate
concentrations
 Gradual volumetric change not immediate (hrs)
 Air bubbles
 Un-uniform distribution of lactate oxidase
Recommendations
 Colorimetric Assay – Gradient of color change for
more specific lactate readings
 Digital Readout – More accurate saliva lactate
readings
 Testing in a public health application – test viability in
large clinical settings (ie. Schools, businesses, clinics)
References
 http://www.who.int/diabetes/publications/en/screeni
ng_mnc03.pdf