Novel Approach to Lactate Sensing

Diabetes Pre-screening ToolChristine Zhang, Stephanie Wu, Joseph Sun,

Wern Ong, Toby Li

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

Problem Statement

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

Diabetes

Indicators/Complications

Heart Disease/Stroke High Blood Pressure Blindness Kidney Disease Nervous System

Disease (Neuropathy) Amputation

Age Ethnicity Weight Family History Other Symptoms

Infections Vision Slow to heal

3 pre-diabetes tests A1C test Fasting plasma glucose test Oral glucose tolerance test

Lactate Sensor Simple More accessible

Current Testing Methods

Diabetes

Testing

A1C

Fasting Plasma Glucose (FPG)

Oral Glucose Tolerance (OGTT)

Prevalence 25.8 million people (8.3%) U.S. population

18.8 million people diagnosed 7.0 million people undiagnosed

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

Diabetes (I & II)

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

Market Potential

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%

Develop lactate sensitive screening device for pre-diabetes screening

Using lactate sensitive hydrogels Measure volumetric change (directional

swelling) Correlate volume change to saliva lactate

Levels Predict probability of developing type II

diabetes

Primary Objective

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

Solution Description

Hydrogel

Volume Change

Supporting Figures

0 2 4 6 8 10 120

2

4

6

8

10

12

f(x) = 0.850823832103762 x + 0.409893044982292R² = 0.957238587803571

Blood and Saliva Lactate Correlation

[Blood Lactate]

[Saliva L

acta

te]

Probability curve

Hygienic Non-Invasive Disposable Uniform Cheap < $10 Easy To Use Accurate

Goals

Polymer Ratio (More DMAEMA = more pH sensitive)

Number of Tubes per batch Concentration of Lactate Oxidase [Lactate] Capillary diameter

Factors

System and Environment

Lactate Sensor

Saliva Sample

Lactate Conc.Water

pH

Proteins

Diabetes Predictio

n

Volumetric Change

Temperature

Lifestyle Change

Blood TestSee

Physician

Self Testing

Clinical Setting

Literature Research

Hydrogel Synthesis

Lactate Sensitive Prototype

Testing Sensitivity to

Lactate

Calculation of Calibration

Curve

Statistics/Analysis

Establishment of real world

protocols

Application Testing

Experiment Block Diagram

Performance

1 222

23

24

25

26

27

28

29

30

31

pH

Batch 1 (Normal)Batch 2 (DMAEMA)

Sample

Volu

me (

mm

^3)

Performance (Cont.)

0 0.2 0.3 0.4 0.5 1 50

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Batch 7

Lactate Conc. [mmol]

Heig

ht

Change (

mm

)

Hygienic Non-Invasive Disposable Uniform Cheap $0.23/tube

Conclusion

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

Informal Observations

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)

Recommendations

http://www.who.int/diabetes/publications/en/screening_mnc03.pdf

References