Presentation on theme: "ITEST 2011 - 1 Chemical Engineering DEMos & the Medical microDevice Engineering Research Laboratory Dr. Adrienne Minerick ITEST High School Enterprise."— Presentation transcript:
ITEST Chemical Engineering DEMos & the Medical microDevice Engineering Research Laboratory Dr. Adrienne Minerick ITEST High School Enterprise summer teachers' workshop
ITEST Lab on a Chip Device
ITEST Medical Laboratory Future Microdevices Time Days Minutes Cost Sample Volume $$$ Milliliter $ < Drop Variability in testing Technician error False 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 Fabrication of Microdevices
ITEST 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 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 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 M.D. – ERL Devices PDMS Channels Si wafer – “Master” A F ED CB A F ED CB A F ED CB
ITEST 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 Average Annual Earnings for College Graduates and Non-Graduates
ITEST Engineers / Scientists make more than other majors & they also have a very positive impact on society
ITEST Timeline Birth ~75 Death 15 College $30,000 $63,000
ITEST Chemical Tech Considering graduate school? Professors hire students in research laboratories NSF sponsored Research Experience for Undergraduates (REU) Undergraduate Research
ITEST Contact me at: Adrienne Minerick
ITEST 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 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 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 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- e-e- - + Anode Cathode Seasoned DEMo: Charged up on Electrophoresis
ITEST Advisory 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 CO 2 – Necessity for separations
ITEST 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.
ITEST For each team of 2 students
ITEST 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
ITEST 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
ITEST 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. 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.
ITEST 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 22.3 o C, 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?.
ITEST Determine by performing an energy balance at the surface Energy 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)
ITEST 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 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.
ITEST 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.
ITEST 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]
ITEST 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]
ITEST 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
ITEST Diffusion vs. Convective Mass Transfer Molecular Diffusion: : D=10 -7 cm 2 /s Diffusional Time Scale: h=width of channel Convection Use Peclet number to compare to diffusion Estimate Velocity, U Calculate Pe
ITEST Human Erythrocytes ABO Typing System: Landsteinner in 1900  – 2 main antigens A: N-acetyl-D- galactosamine B: N-acetyl-D-glucosamine 7microns 2microns O2O2 CO 2 “Red Blood Cells” o8.html Rhesus Factor: Presence = positive blood type (Absence = negative) ~85% of population exhibits Rhesus Factor  ~1.5 million antigens per cell   Landsteiner, K. 1900 Dailey. Blood, 1998 Minerick, A.R. AIChE Journal
ITEST 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 channels Impact 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 Buffer Conductivity= 50 mS/cm; 10 X magnification A-: 5 min 0.25 s interval
ITEST Experimental Setup – 1kHz Experiments Dilute blood with PBS Load into microdevice Hook up to Signal Generator Video Images from Zeiss Every 15 sec for 15 min Automeasu- rement Program Overall picture of rupturing
ITEST For each image, the fraction of ruptured cells was calculated from raw data showing the amount of cells present in the field of view Time Dependent Rupturing
ITEST Natural pH Gradients Macounova, et al. Anal. Chem. 72 (2000) 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)
ITEST pH gradients in microchannels can affect transport – Conductivity affects Debye length and EOF – Complicates prediction of system behavior cm cm Fluorescence of CI-Nerf along capillary was measured. Intensity increase indicated a pH increase of 4.5 Minerick, et al. Electrophoresis 24 (2003) Reproduced 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 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 ACTIVITY: Hydrolysis Reactions Driven by Electric Fields Lead to pH Changes ANODE (oxidation): CATHODE (reduction):
ITEST 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 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 Kaela Leonard Dr. Soumya Srivastava Aytug Gencoglu Chung Ja Yang Angela Dapolite Sean Duke Courtney Lentowich Dr. Adrienne Minerick 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)