Control Circuit Design

1
Control Circuit Design
POWER SOURCE
TIMER
BIOSENSOR
MICROPROCESSOR
DEMULTIPLEXER
MINIATURIZED MULTI-WELLED DRUG DELIVERY DEVICE
2
Thin-Film Battery

• Ion flow through electrolyte
• Electron flow through external circuit

• Flow driven by the redox reaction between anode
  and cathode

3
Battery Design
Cathode LiCoO2 Anode Li metal Electrolyte
lithium phosphorus oxynitride

• Dimensions 15 mm thick
• 1 cm2 area

Power capabilities 3-4.2 V at 2 mA/cm2
(.2 mAh/cm2 ) 25-37 C Rechargeable
4
Release Mechanism Gold Dissolution
Potential E(V) vs. SCE
5
Scaling in Electrochemistry
X?2D?
D -diffusion coefficient ? -time required
for molecule to diffuse x -distance molecule
diffuses
Diffusion over 10 ?m is a millon times faster
than diffusion over 1 cm
6
Power Requirements
VIR
PIV
LESS than the battery capacity!
7
Final Device Dimensions
17mm x 17mm x 315?m Reservoirs 400 total .05
mm spacing (bottom side) 25 nl volume Square
pyramid side wall slope 54? Fill opening 500mm
x 500mm Release end 30mm x 30mm Gold caps
50mm x 50mm x .3mm
8
Drug Delivery Schedule

• Depends on patient need
• 400 reservoirs - flexible
• type of drug
• amount of drug

• Example delivery
• 25 nl x day (1 reservoir)
• With 400 reservoirs, device lasts OVER A YEAR!

9
Conclusions

• The microchip for drug delivery described allows
  for storage and dependable controlled release of
  multiple drugs.
• The microchip can be created by general
  microfabrication techniques.
• This device can be self-contained and therefore
  eliminates the need for patient intervention.
• The proposed device described (assuming one dose
  per day) can last over a year.