Education Activities of Bioengineering for Undergraduate Students at UMBC L. Zhu, D. Arola, C. Eggleton, A. Spence Department of Mechanical Engineering University of Maryland Baltimore County Baltimore, MD 21250

Interdisciplinary Research  Recent developments in micro- and nano-technology have provided many new research opportunities in bioengineering for better imaging, diagnosis, therapeutic therapy, and monitoring progression of various diseases.  Biology and Chemistry are becoming highly quantitative disciplines, dealing with deeply complex interacting factors. Engineered systems are increasingly integrating biological concepts into traditional methodology.  These are unique challenges often requiring interdisciplinary collaborations among researchers with diversified expertise.  It is important to educate the next generation of undergraduate students to cultivate opportunities for interdisciplinary problem solving and to prepare them for those challenges.

 University of Maryland Baltimore County (UMBC) actively promotes interaction between students and faculty, undergraduate participation in research projects and service to the community.  Despite these efforts, very few undergraduate students on campus attend regular research seminars and workshops in the STEM departments and less than 10% of the undergraduate students actively participate in research.  Most of the graduate students are international students. There lacks a pipeline of domestic students pursuing advanced degrees in STEM fields.  Extra efforts are needed to change undergraduate students’ attitude towards research, especially interdisciplinary research. Challenges

Objective  To provide an educational framework for engaging mechanical engineering undergraduate students in an interdisciplinary area combining traditional Mechanical Engineering principles with biomedical applications, via  course innovation with special emphasis on active learning  special educational activities to foster interests in undergraduate research.

Development and Modification of “Bioheat Transfer”  This course was developed to introduce fundamental knowledge of engineering and biology to students who have a general interest in biomedical engineering.  It is cross-listed for graduate students and upper-level undergraduate students in the Mechanical Engineering department at UMBC.  The prerequisite is undergraduate heat transfer course.  This course has been offered several times in the past in the Mechanical Engineering Department at UMBC.  Typical class size was 8 – 12 students per semester.

Course Materials  A chapter from “Biomedical Engineering & Design Handbook, Volume 1: Bioengineering Fundamentals. pp , Myer Kutz, editor-in-chief, McGraw-Hill,  Class notes (pdf files)  Handouts  Commercial simulation software  Homework assignments

Course Contents (14 weeks) 1. Early History and Current Developments in Bioheat Transfer (1 week) 2. Introduction to Heat Transfer in Biological System (2 weeks) Hemodynamics of blood flow, Thermal regulation and blood flow, Fundamental concepts of bioheat transfer 3. Bioheat transfer modeling (2 weeks) Different approaches in bioheat transfer modeling, Continuum model (Pennes, Weinbaum-Jiji, etc.), Model validation by experiments and vascular model, Theoretical modeling of the whole body 4. Temperature, blood flow and thermal property measurements (3 weeks) Temperature (Invasive temperature sensors (thermocouples and thermistors), Non-invasive temperature measuring devices (thermal image and MRI)), Thermal property (Difficulties encountered for biomaterial, Theoretical determination of thermal properties, Experimental techniques (hot plate, flush method, needle probe, & TPD)), Blood flow (Radio-labeled microsphere, strain gauge plethysmography, doppler ultrasound, laser Doppler flowmetry, TPD) 5. Hyperthermia Treatment for tumors and cancers (4 weeks) Temperature monitoring during thermotherapy, Heat patterns induced by hyperthermia applicator, Hyperthermia treatment volume and ideal temperature distribution, Relationship between SAR (specific absorption rate) and its generated temperature field, Currently Used Heating Devices (high energy DC shock, RF, microwave, laser photocoagulation, & Ultrasound, as well as nanoparticle hyperthermia), Determination of SAR, Dynamic response of blood flow to hyperthermia, Theoretical modeling the temperature distribution during hyperthermia, Thermal damage assessment 6. Students presentations (2 weeks)

Course Evaluation Four Homework Assignments (6-8 questions/each)30% Term paper reading, rewriting and presentation50% Final Exam (two hours)20%

Typical Homework Questions Blood flow to the human brain can be modeled as a parallel and series system consisting of two large arteries (the carotid, 5 mm dia., and 250 mm long), two hundred small arteries (0.5 mm dia., and 15 mm long), twenty thousand arterioles (0.05 mm dia., and 1.5 mm long), and two million capillaries (0.01 mm dia., and 0.05 mm long). See the figure for the arrangement. Assume that the total pressure drop from the entrance of the carotid artery to the exit of the capillaries is around 120 mmHg. Blood viscosity  is 3 x N s/m 2. Calculate the flow resistance in each vessel generation and draw schematically the pressure distribution from the large arteries to the capillaries. Estimate the total blood flow rate (ml/min) to the brain. If the total cardiac output is 5.5 x 10 3 ml/min, what is the percentage of blood is supplied to the brain? Find out the typical percentage of the brain weight to the body weight in the humans from internet. Why the percentage of blood supply to the brain is large (or small)? Convert everything into SI unit during calculation.

Suppose that the head can be modeled as a hemisphere (radius r 0 =90 mm) with a single layer of brain tissue. The bottom of the hemisphere is insulated. The head surface is assumed exposed to a convection environment (h=8 W/m2K, Tenv=25  C). Based on the boundary conditions, the brain tissue temperature can be treated as one- dimensional, i.e., Tt(r), where r is the radius in the spherical coordinates system. Metabolic heat generation in the brain is uniformly distributed and is equal to W/m3. Consider two situations, a) no blood perfusion is considered; b) blood perfusion rate  is uniform in the brain and is equal to 0.01 (1/s). Write the governing equation (steady state) and boundary conditions for both situations (using Pennes bioheat equation for situation b). Compare both curves. What is the role of blood perfusion rate on the temperature field? head Convection environment

Final Exam Questions During winter time the hands (without gloves) and the head (without cap) are the major places losing heat to the environment. Suppose both the hands and the head have the same surface area A and are subjected to the same convective environment (same h and T air ). Please explain why the head losses more heat (Q head ) to the environment than the hands during the winter. Explain the temperature transients observed in an experiment

Term Paper   Each student selects a research paper from any website. The paper is bioheat transfer related.   Students read the paper and understand as many details as possible.   Students re-write the paper based on their own understanding of the research contents.   Students prepare a 15-slide powerpoint file and present it in front of other students and answer questions.

Results   The average GPA of the undergraduate students was 3.62/4.00, which was similar to the GPA of the graduate students in the course.   Student’s evaluation of the instructor and their comments to the course were very positive and encouraging. They felt that they have learned an important research area.   One thing they liked the most was the term paper. The required powerpoint presentation of the term paper provides an opportunity for the students to polish their oral communication skills.   Students have commented to have a lab component added to the curriculum.   The elective course was one of many factors for the students to decide to pursue graduate school after their graduation from UMBC.

Conclusions   It is important to stimulate students’ interests in bioengineering during their freshman and sophomore years to establish a habit of participating in research activities such as seminars, workshops, etc.   Their interests can be further enhanced through upper level bioengineering courses designed suitable for undergraduate students.   Required research and educational activities are necessary to prepare our undergraduate students to identify employment and/or paths for graduate study.

Acknowledgement   This research was supported by an NSF S-STEM grant DUE and an NSF education grant CBET