Disposable Drug Pump
TeamCullen Rotroff, Malini Soundarrajan,
Kailey Feyereisen, Tyler Allee
BME 200/300October 14, 2005
Client Michael J. MacDonald, M.D.
Head, Pediatrics Diabetes and Endocrinology Division
Director, Children’s Diabetes CenterUW Hospital and Clinics
AdvisorProfessor William L. Murphy, PhD
Department of Biomedical Engineering
Problem Statement
• Alternative method of drug delivery
• Disposable
• Small
• Light
• Inexpensive
• Comfortable
• Discrete while in use
Overview
• Background on Diabetes and Insulin
• Competition
• Design requirements
• Alternative designs– Hydraulic design– Square wave actuation– Hydrogel Valve and Actuator
• Future work
Type I Diabetes Background • Autoimmune response attacks beta cells in
pancreas• Beta cells make insulin for body• Insulin converts glucose in blood into useable
form of energy or glycogen for storage in liver, muscle, or fat
• High glucose levels cause blurry vision, blindness, nerve damage, kidney failure, heart disease
• Low glucose can cause weakness, irritability, headaches, and seizures
Insulin• Large protein, cannot pass transdermally
• Can’t be ingested via pills
• Two necessary delivery forms– Bolus injection
• Given just after meals and snacks• Onset, peak time, and duration
– Basal rate• Rest of day, basic metabolic needs• Our focus for design
Competition• Hydrogel Microfluidic Dispenser
– Valve actuator interaction– Research phase
• Microspheres– Slow release capsules– Research phase
• MiniMed Paradigm 712– Glucose meter with responsive
pump– $6,195
Design Requirements
•Delivers insulin at a constant flow rate (between 10-50 micro liters)
• For use between 8-24 hrs
• Size of a quarter
• Disposable
• Minimal error
Design 1
• Fluid driven plunger
• J-shaped tube
• Fluid height determined by
flow rate from reservoir tube
• Reliant on Gravity
Design 2
• Microprocessor– Powered by 9 V battery– I/O voltage outputs
• Hydrogel Actuator– Electrically stimulated by
electrodes
• Drug Reservoir– 1.2 mL capacity
• 50 µL/hr flow rate
Design 3• Uses electrically driven
Hydrogels– Contracting valve– Expanding actuator
• Delivers 50-1 µL doses/hr
• Powered by Parallax BS1 Microprocessor
Future Work
• Actuating System– Hydrogels
• Which Ones?• Expansion Rate?• Surrounding Fluid?
– Piezoelectric System• Cost?• Size?
• Prototype– Final Dimensions?– How often will it inject
How much?– Production– Testing