• Cryopreserving intact tissue is an important biological function in the biomedical industry and is dependent on cell membrane permeability to water• There is a lack of techniques to measure cell membrane permeability, but fluorescence quenching is promising • A fluorescent dye, calcein is quenched by molecules in the cell cytoplasm• Fluorescence color intensity is observed during cell exposure to isotonic and anisotonic (salt and no salt) solutions using a fluorescence microscope

• Linear relationship between fluorescence intensity and cell volume is observed

• Design flow chamber to measure cell membrane permeability of intact tissue under strict environmental conditions• Use fluorescence quenching technique to observe cell membrane reaction to anisotonic and isotonic solutions• Fluorescence intensity increases upon cell swelling and decreases upon cell shrinkage We thank Dr. Adam Higgins for sponsoring the project, Dr. Phillip Harding for

guidance, HaiYue Han for helping with SolidWorks, Steve Adams, William Murray and his students, and Andrew Brickman for fabricating the flow chamber, and Dr. AlexandreYokochi for his helpful suggestions.

1. Explore different tubing sizes and materials2. Integrate flow chamber with fluorescent

microscope3. Vary temperature of solutions passing over the

cells to mimic cooling conditions

BACKGROUND

Isotonic Hypertonic

DESIGN OF A FLOW CHAMBER FOR MEASURING CELL MEMBRANE PERMEABILITY Laura Dennis and Matthew Coblyn

OSU School of CBEE, CHE 415-416

PROCESS DESCRIPTION

PURPOSE AND HYPOTHESISFUTURE WORK

ACKNOWLEDGEMENTS

Gasket

Glass coverslip with cultured cells

UV lightsource and microscope

Cross-section of flow chamber

A salt solution is pumped from syringe to flow chamber housing. It then enters the heat exchanger, which consists of 27 cm of 1/16” Tygon tubing bathed in heating/cooling fluid which is continuously circulated with the water bath source. The salt solution immediately enters the flow chamber after exiting the heat exchanger.

Water bath

Flow chamber

Thermocouple reader

Syringe Pump

Side view of chamber

Create salt concentration profiles that model a step change in concentration by eliminating the inlet tubing preceding the flow chamber that both salt solutions must flow through, thereby minimizing mixing.

PROGRESS TO DATE

Figure 1 Cell swelling and cell shrinking as a function of exposure to isotonic and anisotonic solutions, respectively.

Figure 3 Effects of hi, ho, and ktubing on the overall heat transfer coefficient.

Figure 2 Experimental values are plotted along with theoretically expected trends. Flow rate refers to the tube side flow. High and low pump settings refer to the water bath pump that flows fluid through the shell side. Tube 1 and tube 2 refer to the two separate tubes within the heat exchanger that feed the flow chamber different solutions

Nu1.86 RePrDL

13hDk fluid

0 50 100 150 200 250 300 350 4000

20

40

60

80

100

120

140

High pump setting, tube 1

High pump setting, tube 2

Low pump setting, tube 1

Theoretical, Low pump setting

Theoretical, High pump setting

Flowrate (ml/hr)

U (W

/m2-

K)

0.1 1 100

50

100

150

200

250

300

350

400

450

ho hi k

Factor change from theoretical value

U (W

/m2-

K)

ln( / )1 12

i o i i

i tubing o o

D D D DU h k D h

Re D

Pr CPk fluid