A Novel Approach to Lactate Sensing Christine Zhang, Stephanie Wu, Joseph Sun, Wern Ong, Toby Li Greeting, name, education, topic

Objectives Problem Statement Market Potential Background Design What is lactate? Why is it important signal? Design Goals Challenges Current Status Start with motivation, then background, then design options and current progress Why is lactate important signal?

Problem Statement According to the CDC and WHO, there is a need for a: Cheap Uniform Reliable Accurate Easy-to-use …predictor for prediabetics Imagine you’ve been training for the ironman 70.3 austin, sweating, and working hard for months so you can really own the competition…. During that training, your anaerobic threshold is critical b/c it determines how intensely you can work out before you cause nasty side effects. Highly correlated with anaerobic threshold, sensitive predictor of type ii diabetes and indicator of disease progression

Current Testing Methods Fasting Blood Glucose Test Fast overnight Go into clinic Take blood glucose measurement Drink a 75g sugar beverage Take blood glucose measurement 2 hours later Common Complaints Nausea Pain Long wait time

Market Potential Type II Diabetes 170 million worldwide, 20.8 million US 300 million by 2025 – WHO prediction Diabetes is a $15 billion dollar industry There are nearly 1 million sports enthusiasts who don’t have the financial resources of professional athletes… selling an inexpensive unit at a reasonable $30/unit would lead to $30 million. fabrication of sensor depending on location would be less than a $1. profit margin is huge! Not to mention potential to expand into emergency care by providing paramedics and er doctors with method to easily measure ischemia due to stroke

Background What is lactate? Why is it important? Byproduct of anaerobic metabolism - little O2 in environment Commonly thought to cause muscle soreness Why is it important? Indicates oxidative capacity what??? Can occur during intense exertion, ischemia (when tissue is not getting enough oxygen)

Simply put… Oxidative capacity is the ability of tissue to produce energy efficiently from available oxygen Anaerobic threshold gives the critical lactate levels when production >> removal and buildup in blood occurs

Correlation Between Lactate and Diabetes Lactate levels are a predictor of type 2 diabetes

Saliva and Blood Lactate Levels Saliva and blood lactate levels show high correlation Current performance evaluation systems only give athletes option of blood lactate sensing in clinical environment Expensive – techs, healthcare professionals Comfort - Cumbersome equipment, painful Literature search has revealed that blood lactate and saliva lactate levels are highly correlated with short lag times, if any Curves highly correlated in figure. Red-blood, blue – lactate Though peaks are different, its really 2nd derivative curve we’re most interested in (rate of change in slope) Mouthguards are commonly used in high impact sports and would be convenient platform to host sensing equipment Embed lactate microfluidic sensor in molded plastic Sensor captures pooled saliva, uses lactate dehydrogenase enzyme to convert to concentration of lactate to electrical current Current measured and read out by some adc unit

Design Lactate thermometer like device – Lactometer Hydrogel that changes color based on lactate levels Readable for the user

Design Goals Hygienic Non-invasive Inexpensive Easy to use Accurate Produce a novel method for monitoring lactate anaerobic threshold in exercise situations that is…

Performance Metrics Lactate sensing $1.00 per test 0.1 mmol resolution – if digital Range 0.15 – 0.3mmol 0.2mmol indicator level $1.00 per test Blood lactate levels range from 1-2mmol resting, up to 20 mmol during intense exertion

Market Competition Accutrend Plus System Roche Diagnostics $190 Measures glucose, cholesterol, triglyceride and lactate

Solution Overview Hydrogel filled capillary detects lactate levels in saliva Hydrogel swelling indicates lactate concentrations Prediabetics confirm presence of type II diabetes or probability of type II diabetes

Current Status Currently testing pH sensitive hydrogels coupled with lactate oxidase 2-hydroxyethyl methacrylate (HEMA) N,N,dimethylaminoethylmethacrylate (DMAEMA) Tetraethylene glycol dimethacrylate (TEGDMA) Crosslinking agent Lactate oxidase

Website http://www.bme.vanderbilt.edu/srdesign/2010/group11/ I encourage everyone to visit our site… I wrote part of the code myself

Questions?