Electroporation MIT 3.042 Project Ami Yamamoto Joy Yuan Jennifer - - PowerPoint PPT Presentation

Electroporation

MIT 3.042 Project Ami Yamamoto Joy Yuan Jennifer Liang John Tejada Paulo Jacobs

From Last Time…

Goal: To design a more durable water disinfectant system that requires lower energy input. Method: Electroporation to lyse bacteria cells. Formation of pores in the cell membrane due to exposure to high voltage electric fields Proposed Design: 2 parallel electrode sheets

+ _ Power Supply Water Water & Pump

Electrode Material

Requirements

Minimal corrosion at the surface Relatively inert with water Operate under high voltage

Potential Candidates

Titanium

Low errosion rate Commonly used for electroporation Can be anodized: corrosion-resistant

Stainless Steel

Lowest errosion rate

Cathode: Ti Anode: Anodized Ti

Pressure Limitations

pressure difference vs. gap size

2 4 6 8 10 12 14 16 10 20 30 40 50 60 70 80 gap size (microns) pressure diff (atm)

achievable pressure differential

Derived from Couette flow: ∆P = 3µLQ 2Wδ3

Set electrode dimensions: 5 cm x 5 cm Set flow rate Q: 1 liter/hour To remain in a zone of achievable pressure differential, must have gap size greater than 20 microns.

Pressure Limitations

Derived from Couette flow: ∆P = 3µLQ 2Wδ3

Set electrode dimensions: 5 cm x 5 cm Set gap size 2δ: 25 microns To achieve a target flow rate of at least 1 liter/hour, must have pressure difference greater than 2 atm.

pressure difference vs. flow rate

1 2 3 4 5 0.E+00 1.E-07 2.E-07 3.E-07 4.E-07 5.E-07 6.E-07 flow rate (m^3/s) pressure diff (atm)

Flow rate = 1 liter/hour

Voltage Limitations

+ _ Electric Field needed for Lysis: E = 1-5 × 105 V/m

• Verhes. Water Research, 2002.

P = IV = ∆E ∆t ∆E = V2 ∆t R V = Ed

Voltage Limitations

Breakdown potential of H2O = 1.23V Gap size = 12.3 µm Diameter of E. coli = 2-6 µm V = Ed + _ Power Outlet = 50V Gap size = 500 µm = 0.5 mm

Flow Orientation

r

+ _

E

Flow Orientation

r

+ _

E

Cylindrical Configuration

Final Shape Design