an introduction to biomedical engineering aaron glieberman august 3rd, 2010

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An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

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Page 1: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

An Introduction to Biomedical Engineering

Aaron GliebermanAugust 3rd, 2010

Page 2: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Bureau of Labor Statistics, U.S. Department of Labor, 2010

Page 3: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Earnings distribution by engineering specialty, May 2008

Bureau of Labor Statistics, U.S. Department of Labor, 2010

Page 4: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Average Starting Salaries: July 2009 survey by the National Association of Colleges and Employers

Bureau of Labor Statistics, U.S. Department of Labor, 2010

Page 5: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Why Biomedical Engineering?

Promising future developments

Improve medicine, save lives

Numerous possibilities based upon level of biology and engineering specialty

“Hybridization” of skills and knowledge

And, of course. . . .BIOLOGY!

Page 6: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Types of problems

Interface between biological and non-biological materials

Design, modeling, and construction of biologically-analogous technologies

Understanding and improving upon biological limitations

Medical tools and diagnostics

Page 7: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Overview

Terminology, disciplines, curriculum

Case Study: Heart and lung machine

Case Study: Neuroengineering - neural prostheses

(If there’s time - Case Study: Biochemical Engineering – tissue regeneration)

Lab visit: Mathiowitz Lab

Page 8: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Overview

Terminology, disciplines, curriculum

Case Study: Heart and lung machine

Case Study: Neuroengineering - neural prostheses

(If there’s time - Case Study: Biochemical Engineering – tissue regeneration)

Lab visit: Mathiowitz Lab

Page 9: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

TerminologyBiomedical engineering

Bioengineering

Also, “biological engineering” and others . . .

Biotechnology

Often used interchangeably with “biomedical engineering”. When distinguishing between the two, typically bioengineering tends to refer to engineering using biological substances, often at a higher level of biology than biotechnology.

The use of engineering science and math to tackle problems in medicine. When distinguished from “bioengineering,” focuses more on the machine/device/non-biological type of research.

Term that is generally similar to “bioengineering,” but, in comparison, refers most specifically to direct manipulation and use of living biological substances.

Page 10: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

DisciplinesBiomechatronics

Bioinstrumentation

Biomaterials

Biomechanics

Aims to integrate mechanical, electrical, and biological parts togethere.g. sieve electrodes, advanced mechanical prosthetics

Construction of devices for measuring aspects of physiological status e.g. Electrocardiography (EKG), Electroencephalography (EEG),

Development of materials either derived from biological sources or synthetic, generally used for medical applications

Study of mechanics as applied to biological structures

e.g. Biopolymers, scaffold material for tissue engineering, coating for transplants

e.g. Musculoskeletal mechanics, trauma injury analysis

Sieve electrode design

12 lead EKG configurations

Page 11: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

DisciplinesBionics

Cellular, tissue, genetic engineering

Medical imaging

Bionanotechnology

Also known as “biomimetics”, using biological mechanisms as an inspiration for engineered technology

e.g. gecko grip, velcro, architectural features

Manipulation of living cells to replace/improve existing functions or to impart unique function

e.g. X-ray, CAT, MRI, fMRI, PET, ultrasound

Visualization of anatomy and physiology, essential for modern diagnosis and treatment

e.g. GMO crops, tissue regeneration

e.g. DNA nanotechnology and computingCombination of nanotechnology and biology

Gecko foot and carbon nanotube imitation

Set of fMRI data

Boxes made with “DNA origami”

Page 12: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

In general

Focus on a specific type of engineering to create a desired hybrid between biomedical and other, more established fields

Chemical engineering – cellular,tissue engineering, biomaterials, biotransport

Electrical engineering - bioelectrical and neuroengineering, bioinstrumentation, biomedical imaging, medical device design, optics

Mechanical engineering –biomechanics, biotransport, medical devices, soft-tissue mechanics, biological systems modeling

Page 13: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Biomedical Engineering curriculum at Brown

Basic engineering (statics, dynamics, electromagnetism, thermodynamics, fluid mechanics)Basic chemistry (including organic)Basic math (multivariable calculus, statistics, differential equations)Basic biology or neuroscience (including physiology)

Engineering core

Bioengineering courses

-Transport and Biotransport Processes-Tissue Engineering-Biomaterials-Biomechanics-Neuroengineering-Analytical Methods in Biomaterials-Molecular and Cell Biology for Engineers-Biophotonics-Synthetic Biological Systems/Synthetic Biological Systems in Theory and Practice

-Organ Replacement-Animal Locomotion-Drug and Gene Delivery-Techniques in Molecular and Cell Science

Page 14: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Accreditation Board for Engineering and Technology (ABET) is a non-profit organization composed of numerous smaller professional societies that evaluates degree programs and awards accreditation if the program matches academic criteria

Accreditation

Since BME is a new field, should pay attention to this for the school you attend

Important should you wish to become recognized as a professional engineer

Page 15: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Case Study: Heart and Lung Machine

Involves biotransport, gas exchange, fluid flow

Replaces roles of heart and lungs during surgery

Page 16: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Blood

Oxygenated blood is red

Average adult human contains 4-5 L of blood

Hemoglobin (Hb), a protein contained within red blood cells, can carry oxygen with its heme groups

4 oxygen-binding sites

Page 17: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Physiology of Oxygen Transport – Circulatory system

Heart is a pump, a muscle that transports blood through body

4 chambers – left and right atrium and ventricle

Flow rate of blood out of heart is called “cardiac output”

Two main circulatory paths

Pulmonary – oxygen-depleted blood pumped from right ventricle to lungs, blood collects oxygen from lungs and sends it back to left atrium

Systemic – oxygen-rich blood pumped from left ventricle, deposits in body tissues, returns to right atrium

Also, coronary – oxygenated blood is supplied to heart cells

Pulmonary

Systemic

Page 18: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Physiology of Oxygen Transport – Cardiac Output

Cardiac output (Q) can be measured in terms of stroke volume (SV) and heart rate (HR):

Q = SV x HR

stroke volume is the amount of blood pumped by a single ventricle in a unit of time

A reasonable value is 70 mL

heart rate is the rate of contractions that the heart makes per minute

Normal adult heart rate ranges between 60 and 100 beats per minute

Resting cardiac output (Q) = 0.07 L x 100 bpm = 7 L/min

Exercising example: SV = 65 mL, HR = 175 bpm

cardiac output (Q) = 0.065 L x 175 bpm = 11.4 L/min

Page 19: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Physiology of Oxygen Transport – Cardiac Output

Blood flow (Q) in a vein/artery or tube derives from the Hagen-Poiseuille formula:

ΔP = pressure difference between contraction and relaxation of heart (in kPa)

r = radius of tube

L = length of tube

μ = dynamic viscosity (in N*s/m2)

Page 20: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Physiology of Oxygen Transport – Respiratory system

Composition of air by volume:

78% nitrogen, 21% oxygen, 0.03% CO2

Oxygen enters body through nose/mouth

Travels down airway into alveoli

Gas exchange occurs between alveoli and capillaries driven by pressure gradient High O2,

low CO2High CO2, low O2

Page 21: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Oxygen saturation

Pressure at tissue Pressure at alveoli

Oxygen delivered

pO2 = 100 mm HgpO2 = 40 mm Hg

Page 22: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Heart bypass surgery

Surgery wherein blood flow bypasses the heart and lungs, since operating on an active heart is difficult to accomplish

Coronary artery bypass surgery/graft (CAPG) entails grafting vessels from elsewhere in the body to reroute blood flow around blocked regions in the coronary arteries

For the past half century, has utilized artificial pumping and oxygenating, which is accomplished by the heart-lung device

Page 23: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Heart and Lung Machine

(Perfusionist is trained technician who can operate the heart and lung machine)

First attempted surgery with heart and lung machine in 1951 by Dr. Clarence Dennis

First successful surgery in 1953 by Dr. John Gibbon

Page 24: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Heart and Lung Machine, Components

Pump

Oxygenator

Roller pump –ciruclating rotor physically displaces fluid through tubing

Centrifugal pump – motion of fluid through an impeller (a type of rotor) propels the liquid forward

Connective tubing – PVC or silicone rubber

Traditionally, a bubble oxygenator was used, but this has since been replaced by membrane-coated oxygenators

Page 25: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Heart and lung machine, phased out?

Circulation. 2003 Sep 9;108 Suppl 1:II1-8.

Page 26: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Case Study: Neural prostheses

Potential for overlap between chemical, electrical, and mechanical backgrounds

Restoring lost neurological function

Page 27: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Neural prostheses - Neurons

Neurons are a specialized form of cell

Signaling via chemical and electrical impulses

Responsible for quick information transfer in the body

Page 28: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Neural prostheses – BrainGate

Project based at Brown hoping to restore some activity to quadriplegics

Page 29: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Neural prostheses – BrainGate

Calibration tests

Monkey plays game with joystick, moving arm in response to visual cues

As the monkey’s arm moves in the desired direction, brain activity is recorded

This firing activity must be decoded to understand the correlation between firing pattern and directional movement

Page 30: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Neural prostheses – A different approach

Targeted muscle reinnervation (TMR)

Relocate nerves from arm to chest

Electrode picks up neuron firing in chest

Software analyzes firing and drives actuator

Page 31: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Neural prostheses – Robotics technology

Research on replicating human function

Sensory feedback

Challenges:

Linking to biological inputs

Complexity of biology (arm alone is controlled by more than 70 muscles)

Controlled strength

Page 32: An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010

Neural prostheses – Cochlear implants