ITEST 2011 - 1

Chemical Engineering DEMos & the Medical

microDevice Engineering Research Laboratory

Dr. Adrienne MinerickITEST High School Enterprise summer teachers' workshop

ITEST 2011 - 2http://consiliencejournal.readux.org/wp-content/uploads/2008/02/curtis1.png

Lab on a Chip Device

ITEST 2011 - 3

Medical Laboratory Future MicrodevicesTime Days Minutes

Cost

Sample Volume

$$$

Milliliter

$

< Drop

Variability in testingTechnician errorFalse positives / negatives

Reliability

Sia et al., 2003, Electrophoresis Tudos et al. 2001, Lab on a Chip Kim et al. 2006, Lab on a Chip

Point of care test Device variability Reproducible and rapid Operational simplicity

Lab on a Chip Device (2)

ITEST 2011 - 44

www.ims.tnw.utwente.nlwww.niherst.gov.tt

Fabrication of Microdevices

ITEST 2011 - 5

What are students currently interested in?

Cell Phones

Computers

Music

Sports

Gaming Stations

Fishing

Food

Cosmetics

Fashion

Environment

Scientists & Engineers are the basis for all of these!!

ITEST 2011 - 6

Chemical Engineers make the world a better place….

• Civil engineers build bridges, water / sewage conduits• Chemical engineers make the concrete &

engineered it to be stronger, less corrosion resistant• Design bioremediation processes for wastewater

treatment (now even making biofuels from wastewater)

• Mechanical engineers design better engines• Chemical Engineers design synthetic fuels for better

performance, life.• Electrical engineers design better computer chips

• Chemical engineers do the microfabrication

ITEST 2011 - 7

Chemical Engineers even have an impact on health care…

• Students in my lab (Medical micro-Device Engineering Research Laboratory) are designing and testing microdevices to analyze blood samples for point of care medical diagnostics.

ITEST 2011 - 8

M.D. – ERL Devices

PDMS Channels

Si wafer – “Master”

ITEST 2011 - 9

What is Chemical Engineering?

Modern society depends extensively on chemical engineers - they help manage resources, protect the environment, and

control health and safety procedures while developing the processes to make products

we desire or depend on.

Raw materials Valuable

products

Apply chemistry, physics, math, & biology to solve real world

issues

ITEST 2011 - 10

Average Annual Earnings for College Graduates and Non-Graduates

ITEST 2011 - 11

Engineers / Scientists make more than other majors & they also have a very

positive impact on society

ITEST 2011 - 12

Timeline

Birth ~75Death

15

College

$30,000

$63,000

ITEST 2011 - 13

Chemical Engineering @ Tech

Considering graduate school?• Professors hire students in research

laboratories• NSF sponsored Research Experience

for Undergraduates (REU)

Undergraduate Research

ITEST 2011 - 14

Contact me at:Adrienne Minerickminerick@mtu.edu

ITEST 2011 - 15

Subtopics of Chemical Engineering• Analytical Methods & Products• Biomedical• Biotechnology• Ceramics• Chemical Producers and Suppliers• Databases• Education Resources• Electrochemical• Energy, Conservation and Efficiency• Engineering and Construction• Environment• Fluid Mechanics• Forest Products• Heat Transfer• Law School• Mass Transfer

• Materials• Medical field• Nuclear• Particle Technology• Petrochemicals and Fuels• Polymers• Reactions• Process Control• Process Design• Process Modeling• Safety and Hazards• Software Products and Suppliers• Standards• Statistics and Experimental Design• Teaching Topics and Resources• Water Technology

ITEST 2011 - 16

Desktop Experiment Modules (DEMo’s)

• DEMo’s are versatile, inexpensive, and portable experiments

– On student desks throughout a classroom. • Superior to instructor led demonstrations

1. Each student can closely examine and manipulate the apparatus,

2. Student teams can progress through experiment discovery at their own learning pace, and

3. All learning styles are stimulated to maximize understanding of important fundamental concepts.

ITEST 2011 - 17

Target Audiences

• Introduction to Chemical Engineering Courses• Separations Classes• Analysis Class (data collection, analysis, report writing)• Mass or Heat Transport Classes• Unit Operations• Outreach / Recruiting / Retention

– Engage the students– Make concepts come alive– Recruit and retain a broader spectrum of students with new techniques.

ITEST 2011 - 18

• Electrophoresis is a separation tool for biological species (DNA, RNA, proteins, cells)

• Formation of ionic compounds, ionic radii, ionic strength• Electrolysis reactions• pH changes / indicators• Electrophoretic mobility

+ -e- e--+AnodeAnode CathodeCathode

Seasoned DEMo: Charged up on Electrophoresis

ITEST 2011 - 19Advisory Board - 26 April 07

Seasoned DEMo: Brewing with Bioreactors

Demonstrate fermentation (microorganisms conversion of food source to product) – Batch vs. Continuous Process– Mass Balances (global)– Reaction vessel– Population life cycle– Reaction of sugar to CO2

– Necessity for separations

ITEST 2011 - 20

• Learning tool that is versatile, fairly inexpensive, and portable such that it can be positioned on student desks

• Superior to instructor demonstrations because – each student can closely examine and manipulate the apparatus, – student teams can progress through experiment discovery at their own

learning pace, and – all learning styles are stimulated to maximize understanding of important

fundamental concepts.• Engage the students to make concepts come alive• Recruiting to engineering & change the paradigm that engineering

is impossibly difficult– Diversity in undergraduate programs helps feed diversity in graduate

programs.– Can recruit & retain a broader spectrum of students with new techniques.

Desktop Experiment Modules Background (DEMo)

ITEST 2011 - 21

For each team of 2 studentsCost per item

Coffee Cup Warmer $10

CPU Heat Sink with Fan $7

1.5 inch Rods of Al, Cu, Steel Al ($1.25/inch), Cu ($7/inch), Steel ($1/inch)

Blocks of wood, styrofoam, fire brick, drywall, glass (from local hardware store)

Negligible cost (ask for broken pieces)

Fisher Infrared Thermometer (res is 0.1oC, acc is ±1oC)

$30

Heat Sink Compound (Radioshack) $3

9 Volt batteries $0.75

Battery leads (Radioshack) $0.20

TOTAL: $60 per station

Supplies and Setting Up

ITEST 2011 - 22

• One dimensional conduction– Thermal conductivity

• One dimensional conduction in composite systems– Thermal contact resistance

– Transient heat generation

• Steady state heat generation• Heat transfer from extended surfaces (fins)• Convection• Radiation

DEMo Equipment is versatile: demonstrates multiple HT mechanisms

ITEST 2011 - 23

• This concept is illustrated by the IR thermometers utilized in the experiment.– Use blackbody radiation emitted from objects to determine

temperature. – Measure amount of infrared energy emitted by the object– Uses an assumed (constant) emissivity, ε=1

ASEE 2009

Radiation

ITEST 2011 - 24

• This step is necessary at the beginning of each experiment and can be used to remind students that processes are not always at steady state.

Experimental Procedure:– Take initial temperature reading of plate warmer before turned on and record its initial

temperature at time 0.– Turn on the plate warmer and begin stop watch at the same time.

0 100 200 300 400 500 600 700 8000

20

40

60

80

100

120

140f(x) = 0.186900246685168 x + 24.5

f(x) = 0.264619179771816 x + 22.3

Transient Generation #1Linear (Transient Generation #1)

Time (seconds)

Tem

pera

ture

(oC)

At 15-second intervals, take a temperature reading of the plate warmer using the infrared thermometer. Make sure to measure at the same location for each reading.

Continue to take readings until the mug warmer temperature is constant for 45 seconds and reaches steady state.

Transient Heat Generation

ITEST 2011 - 25

• Spatial variations not considered so heat diffusion equation is:

• Assuming constant generation, q, the solution is:

• Using the initial condition that the temperature of the mug warmer was initially at 22.3oC, it is possible to solve for the constant of integration.

• Compared to the data collected

• Take apart mug warmers the plate is primarily aluminum, which has a density of and a heat capacity of .

• Heat generation is

Q: Having assumed constant heat generation, why is the data curved?

.

Transient Heat Generation Analysis

ITEST 2011 - 26

• Determine by performing an energy balance at the surfaceEnergy generated in the plate = energy convected away from the plate

• For relatively still air, measure ambient air Temperature, and thickness of the plate:

• Or heat flux is:

• Current calculated from information on the mug warmer unit

• Obtain electrical resistance (and compare to tabulated values)

Steady State Heat Generation: Analysis

ITEST 2011 - 27

• Mug warmer is a heat source on a wall of a material 1D conduction illustrated at student’s desks – Demonstrate thermal conductivity of different materials

MaterialThermal

Conductivity ( )

Polystyrene (R-12) 0.027Softwood (Fir) 0.12Plaster board 0.17Polycarbonate 0.21Firebrick 1.0High Density Carbon Steel

60.5

Aluminum Alloy 2024 177Copper 401

Turn on mug warmer with block on top and allow system to heat up for 15 minutes.

Check temperature three times at 30-second intervals to ensure the system has reached steady state.

Note temperature at the surface of the mug warmer may be greater than when exposed only to convection.

Replace with new blocks of material allowing it to equilibrate between temperature readings.

One Dimensional Conduction

ITEST 2011 - 28

• Heat diffusion equation for one dimensional, steady state conduction with constant thermal conductivity is

• General solution is:

• Boundary conditions determined from student’s experiment. Example uses polycarbonate block 1 cm thick.

and

• Particular solution in symbolic and numeric form:

• Obtain a different temperature profile for each material.

• Use Fourier’s Law to determine the conduction heat transfer rate.

and

• Can use heat flux from SS heat generation experiment too.

1D Conduction: Analysis

ITEST 2011 - 29

• Heat up plate warmer to reach steady state• Place CPU passive heat sink on the mug warmer and start timer• Measure T at two locations• Repeat with the fan on [data from Christine Lottes and Doug Hall]

0 50 100 150 200 250 300 350 400 4502022242628303234363840

Comparison of Natural vs. Forced Convection

Location 1 (no fan)Location 2 (no fan)Location 1 (fan)Location 2 (fan)

Time (sec)

Tem

pera

ture

(oC

)

HT Fins and Convection: Experiment

ITEST 2011 - 30

• Heat up plate warmer to reach steady state• Place CPU passive heat sink on the mug warmer and start timer• Record until system reaches SS, turn on fan [data from Rachel Blair and Kaneb

Jamison]

0 50 100 150 200 250 300 350 400 450 5002022242628303234363840 Heat Exchanger's Temperature Change with the Fan Off and On

Heat Exchanger (fan on) Heat Exchanger (fan off)

Time (sec)

Tem

pera

ture

(°C)

HT Fins & Convection: Experiment 2

ITEST 2011 - 31

• Time dependent fin temperature expressions are not covered in undergraduate heat transfer courses.

• Ideal to determine T as a function of position not possible with the IR thermometers

• System used as an illustrative visual aid when discussing heat transfer from fins • Most CPU heat sink fins are of uniform cross-sectional area.

– Tip experiences convective heat transfer (boundary condition)– steady state, position dependent temperature distribution is

• Steady state fin heat transfer rate is

• where and

HT from Fins & Convection: Analysis

ITEST 2011 - 32

Diffusion vs. Convective Mass Transfer

• Molecular Diffusion:

: D=10-7 cm2/s• Diffusional Time Scale:

• h=width of channel

Convection Use Peclet number to

compare to diffusion

Estimate Velocity, U

Calculate Pe

ITEST 2011 - 33

Human Erythrocytes• ABO Typing System:

Landsteinner in 1900 [1]– 2 main antigens

• A: N-acetyl-D-galactosamine• B: N-acetyl-D-glucosamine

7microns

2microns

O2

CO2

“Red Blood Cells” http://www.academic.marist.edu/~jzmz/HematologyI/Intro8.html

Rhesus Factor: Presence = positive blood type (Absence = negative) ~85% of population exhibits Rhesus Factor [2]

~1.5 million antigens per cell [3][1] Landsteiner, K. 1900 [2] Dailey. Blood, 1998 [3] Minerick, A.R. AIChE Journal. 2008.

ITEST 2011 - 34

Antigen Structure

Minerick, AIChE J, 2008

ITEST 2011 - 35

Foundation Load an unknown blood sample and identify types based on deflection to

the channel AC-DEP - > 95 % confidence in distinguishing O+

Hypothesis DC-DEP - distinguish blood types based on deflection from an insulating

obstacle, into a streamline and out to the channelsImpact

Fast, inexpensive, reliable, accurate, and point of care device which could be used in emergency situations, accidents, wars, etc

Hypothesized outlet streams

Bifurcation point

Keshavamurthy et al., 2008, proceedings of NSTI-Nanotech

Premise- DC Separation of Blood Cells

ITEST 2011 - 36

Buffer Conductivity= 50 mS/cm; 10 X magnification

A-: 5 min run @ 0.25 s interval

ITEST 2011 - 37

Experimental Setup – 1kHz Experiments

Dilute blood with PBS

ITEST 2011 - 38

• For each image, the fraction of ruptured cells was calculated from raw data showing the amount of cells present in the field of view

0 100 200 300 400 500 600 700 800 900-0.2

0

0.2

0.4

0.6

0.8

1Time Dependent Rupturing

Time (sec)

Frac

tion

of R

uptu

red

Cells B+

Time Dependent Rupturing

ITEST 2011 - 39

Natural pH Gradients

Macounova, et al. Anal. Chem. 72 (2000) 3745-3751

Anode rxn:

Cathode rxn:

Finite number of ions in microchannels allows concentration gradients via mass transfer

Fused silica used in many applications

Silanol groups:

O-H dissociation impacts EOF via -potential

Charge distribution depends on environment (i.e. pH)

Minerick, et al. Electrophoresis 24 (2003) 3703-3717

ITEST 2011 - 40

• pH gradients in microchannels can affect transport– Conductivity affects Debye length and EOF– Complicates prediction of system behavior

0.25 0.75 1.25 1.75 2.25 2.75 cm

+ -+ -

Fluorescence of CI-Nerf along capillary was measured. Intensity increase indicated a pH increase of 4.5

Minerick, et al. Electrophoresis 24 (2003) 3703-3717Reproduced with permission:Minerick, et al. "Development of a pH Gradient in a 20-micron Capillary Microdevice," AES Annual Conference; 2002, Indianapolis, Indiana.

Previous Studies

ITEST 2011 - 41

Paper microfluidics

•Fluid flow driven by capillary action of water in paper -no power required•Channels can be defined by drawing on paper with wax or a Sharpie marker•Lengths of the channel dictate timing of flow into different elements•Hundreds of prototypes can be printed at once with a simple printer

Urine analysis: Brown indicates glucose, blue indicates protein. Sample is wicked from the base of the tree.

ITEST 2011 - 42

ACTIVITY: Hydrolysis Reactions Driven by

Electric Fields Lead to pH Changes

ANODE (oxidation):

CATHODE (reduction):

ITEST 2011 - 43

Hydrolysis in paper

Experimental procedure:•Place a drop of water on strip of pH paper•Wipe off excess fluid with paper towel•Attach lead to 9V battery•Touch the leads on the paper 2 cm apart•Observe pH change indicated by color change•Remove leads from battery•Touch the battery poles on the pH paper•Observe pH change indicated by color change

ITEST 2011 - 44

COMSOL simulation of pH rise due to OH- generated by hydrolysis in a 2 cm channel. x-axis: Position in channel, y-axis: pH

ITEST 2011 - 45

Kaela LeonardDr. Soumya Srivastava

Aytug GencogluChung Ja YangAngela Dapolite

Sean DukeCourtney Lentowich

Dr. Adrienne Minerickminerick@mtu.edu

www.MDERL.org

All work conducted in a certified Biosafety level II (BSL II) laboratory with the approval of

Institutional Biosafety Committee (IBC) and Institute Review Board for the protection of

human subjects (IRB)