An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010.
-
Upload
vanessa-banks -
Category
Documents
-
view
221 -
download
0
Transcript of An Introduction to Biomedical Engineering Aaron Glieberman August 3rd, 2010.
An Introduction to Biomedical Engineering
Aaron GliebermanAugust 3rd, 2010
Bureau of Labor Statistics, U.S. Department of Labor, 2010
Earnings distribution by engineering specialty, May 2008
Bureau of Labor Statistics, U.S. Department of Labor, 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
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!
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
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
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
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.
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
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”
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
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
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
Case Study: Heart and Lung Machine
Involves biotransport, gas exchange, fluid flow
Replaces roles of heart and lungs during surgery
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
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
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
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)
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
Oxygen saturation
Pressure at tissue Pressure at alveoli
Oxygen delivered
pO2 = 100 mm HgpO2 = 40 mm Hg
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
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
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
Heart and lung machine, phased out?
Circulation. 2003 Sep 9;108 Suppl 1:II1-8.
Case Study: Neural prostheses
Potential for overlap between chemical, electrical, and mechanical backgrounds
Restoring lost neurological function
Neural prostheses - Neurons
Neurons are a specialized form of cell
Signaling via chemical and electrical impulses
Responsible for quick information transfer in the body
Neural prostheses – BrainGate
Project based at Brown hoping to restore some activity to quadriplegics
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
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
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
Neural prostheses – Cochlear implants