SIMULATION OF A BIOREACTOR Tiffany Tarrant Todd Giorgio.

SIMULATION OF A BIOREACTOR

Tiffany TarrantTodd Giorgio

What is a Bioreactor?

• Experimental device used to culture cells

• Provides nutrient media, oxygen support, fluid environment, area to grow

• Used both in laboratories and in industry-- specifically used in the lab portion of the BME 281: Biotechnology class

BME 281: Biotechnology

• Course goal: to integrate cellular and molecular biology with process bioengineering to describe the manufacture of products derived from mammalian cells

Why Simulate?

• based on initial lab results

• quicker, more efficient, and less expensive

Experimental Time Comparison

• Laboratory• 22 days to prepare

cells for bioreactor• 5 days to obtain a significant amount of

growth

• TOTAL: 27 days

• Simulation• approximately 1

minute to enter experimental

data and get results

• TOTAL: 1 minute

Typical Cell Culture

• HeLa--common in research labs• ECV304--endothelial cells• 293--used in BME 282 lab

• can be distinguished based on specific growth constants & the extent to which they are affected by local environmental limitations

Cell Types

Past Work

• Modeled simple exponential growth based only on cell-specific growth constant

• Accounted for oxygen delivery limitation

• Introduced different impeller types

Simple Exponential Growth

• unlimited growth

• cell types distinguished based on k

Cell Growth

0

2000

4000

6000

8000

10000

12000

0 50 100 150 200 250 300

time (hours)

cell

conc

entra

tion

(cells

/ml)

HeLa

ECV304

293

Oxygen Limitation Effects

Cell Growth

0

10

20

30

40

50

60

70

0 100 200 300 400

time (hours)

con

cen

trat

ion

(c

ells

*10^

5/m

l)

HeLa

ECV304

293

Impeller

• different types influencing the amount of power that is delivered to the bioreactor system

• increases oxygen dispersal throughout the system, thereby increasing delivery

• forces imposed on cells due to stirring causes mechanical damage and cell death

Impeller Types

Rushton turbine Rushton turbine PaddlePaddle Marine PropellerMarine Propeller

Anchor Anchor Helical ribbon Helical ribbon

Current Work

• Incorporation of impeller effects on growth

• Integration of ISF to balance oxygen delivery capabilities with cell death due to mechanical damage

• Validation of model with actual lab results

• Literature search to investigate other cell culture models

Impeller Effects

Impeller Effects

0

200000

400000

600000

800000

1000000

1200000

1400000

0 100 200 300 400

time (hours)

cell

co

nce

ntr

atio

n

(cel

ls/m

l) Rushton Turbine

Paddle

Marine Propeller

Integrated Shear Factor

Growth vs. ISF

-20

0

20

40

60

80

100

120

0 10 20 30 40

ISF

relat

ive g

rowt

h (%

)

growth

• Cell growth under different shear conditions can be correlated to an ISF factor

Stirring Speed Effects via ISF

• ISF related to speed

of impeller and its distance from the walls of the

bioreactor

Stirring Speed Effects

-50000

0

50000

100000

150000

200000

250000

300000

0 24 48 72 96 120 144 168 192

time (hours)

cell c

once

ntrati

on

(cells

/ml)

100 rpm

250 rpm

300 rpm

350 rpm

400 rpm

600 rpm

Experimental Comparisons

• Given a time lag, model correlates with BME 282 data

Model Data: Lab 293 Cells

0

200000

400000

600000

800000

1000000

1200000

0 24 48 72 96 120 144 168 192

time (hours)

cell c

once

ntrat

ion (c

ells/m

l) Model

Lab Data

Other Models

• No other model attempted to integrate several interrelated factors that affect cell growth

• Instead, focused on one parameter or determining event

• None incorporated oxygen delivery limitations

Program Flowchart

V O L U M E(in p u t ra d iu s & f lu id h e ig h t)

C A L C _ IN IT(in p u t in it ia l co n c .)

P W R N U M _ F U N C(in p u t im p e lle r typ e)

D A M A G E(in p u t im p e lle r sp e e d)

ca lcu la te s IS F

IM P E L L E Rca lcu la tes p ow e r & kLa

O X Y G E Nd e term ine s O 2 s ta te

M A IN(in p u t ce ll typ e)

Parameter Effects on GrowthCell Type Rate of exponential

growth (+)Bioreactor Radius Culture volume (+)

oxygen delivery (-)Impeller Diameter(+)

Impeller Diameter Power delivered tocells (+) & k(-)

ISF-how many cellssurvive damage (-)

Fluid Height Culture volume (+) Oxygen delivery (-)& k (-)

Concentration @each time point

When oxygenbecomes limiting(+/-)

Impeller type Power delivered tocells (+)

Deliverycapabilities (+)

Impeller Speed ISF & powerdelivered to cells(+/-)

Oxygen deliverycapabilities (+)

Future Work

• 1. Slight alterations to the program to make it more user-friendly

• 2. Specific documentation of program procedure and functions