Title: MECH 500: Bionic Implants and Devices
1MECH 500Bionic Implants and Devices
- Sumitra Rajagopalan
- sumitra.rajagopalan_at_polymtl.ca
- Office Hours
- 5pm 530 pm Mondays
- 4 pm- 5pm Fridays
2Bionic Implants Devices Overview
- Layout of Course
- Evaluation Expectations
- What is the course really about?
- Course Prologue
3Course Layout
- Basic Notions in Medical Devices
-
- Functional Biomaterials for Bionic Implants
- Design of Soft-Tissue vs. Hard Tissue Implants
- Implant Surfaces and Interfaces
- Bioactive and Bioresponsive Implants
- Functional Tissue Engineering and Bioartificial
Organs - Bioelectrodes, Artificial Muscles and
Neuroprosthetics - Brain-Machine Interface and Cortical Prosthetics
- Implantable Devices for Minimally-Invasive
Surgery - Biosensors, Bioelectronics, Closed-Loop
Management
4Course Evaluation
- Class Participation 15
- Critical Review of Article(s) OR Case Study 1
20 (Assigned) - Third week of September, due early November
- Case Study 2 25 (Assigned or Chosen)
- Third week of October, due at the end of semester
- Take-Home Exam (5 questions) 40
- December 1st, due December 10th
5What you will get out of the course
- A broad, comprehensive overview of the field
- Study the human body from a materials/mechanical
engineering perspective - Understand and appreciate differences between
living and man-made materials and structures - Custom-design materials and structures to suit
biological function Biomimicry - Design appropriate material surface and interface
- Identify optimal control feedback system for
implant - Understand and appreciate factors governing
behaviour in-vivo - Basic design of biosensors and bioelectronic
implants including Bio-mems and nems - Getting medical device to market
- Apply knowledge of human factors engineering to
extreme enviroments outer space
6So, what is this course really about?
7Medical Devices A Multidisciplinary Enterprise
biology, physiology, biochemistry, immunology
Life Sciences
BIOMATERIALS BIOIMAGING BIONICS BIOMECHANICS BIO
INSTRUMENTATION
electronics, image processing, mechanics,
chemistry, physics, materials, mathematics
Physical Sciences
Engineering
8What is a Medical Device?
- "an instrument, apparatus, implement, machine,
contrivance, implant, in vitro reagent, or other
similar or related article, including a component
part, or accessory which is - recognized in the official National Formulary, or
the United States Pharmacopoeia, or any
supplement to them, - intended for use in the diagnosis of disease or
other conditions, or in the cure, mitigation,
treatment, or prevention of disease, in man or
other animals, or - intended to affect the structure or any function
of the body of man or other animals, and which
does not achieve any of it's primary intended
purposes through chemical action within or on the
body of man or other animals and which is not
dependent upon being metabolized for the
achievement of any of its primary intended
purposes."
www.fda.gov
9Why Bionic ?
1973
1976
1990
2000
10Bionics Inspired by Nature
- Coined by Jack Steeles of the U.S. Air Force in
1960 - Studying Nature from an Engineering/ Design
Perspective - Extracting Structural, Design Paradigms.
- Adopting these paradigms to solve a range of
engineering problems. - Other names Biomimicry,Biomimetics
11Bionic Implant Device
- Implant that mimics as far as possible the
structure AND function of the body part it
replaces. - Interacts with the human body in a bidirectional
fashion - Examples of Bionic Devices Artificial Heart,
Artificial Muscle, Cochlear Implant,
Bioelectrodes, Mechanoactive Cartilage - Towards seamless integration of implant with
physiological environment - Closed-loop system Example of artificial
pancreas.
12Living vs. Man-Made Reflections
13Living Materials, Structures and Machines
- Multifunctional Materials
- Heirarchical, built through self-assembly
- Ordered, patterned, nano-structured
- Graded properties and functions throughout
structure - Seamless integration of materials and structures
of varying properties - Control feedback integrated into structure
- Adaptive
- 3Rs renewing, repairing, replicating
- FORM FOLLOWS FUNCTION
- FORM FITS FUNCTION
14FORM FITS FUNCTION Reflection
- Cartilage?
- Muscle?
- Bone?
- Skin?
15Anatomy of an Implant Design Fabrication
Considerations
- Biomaterial
- Bulk Structure
- Interface
- Implant Anchoring
- Sterilisation Method
- Power Issues in Implant Design
- Wireless Monitoring of Implant
16Biomaterials
- Material intended for implanting in human body
17Smart Materials Bridging Materials to Life
- Shape-memory foams
- Shape-memory alloys
- Polyelectolyte Hydrogels
- Piezoelectric Ceramics
- Electroactive Polymers
- Self-healing composites
- Supramolecular Chemistry
18Bionic Devices Behaviour in-vivo
- Biocompatibility/Cytotoxicity
- Ability to function in-vivo with no adverse
immune reaction - Biodegradability
- Break-down of biomaterial through action of body
enzymes into non-toxic byproducts. - Biostability
- Resistant to break-down in the human body
- Biofunctionality
- Functions as structure intended to replace
19Inflammation Immune System Host Response
- Inflammation occurs through foreign body
response, movement of implant - Protein layer formed on implant surface
- Even "inert" materials cause inflammation
- Inflammation reaction can adversely affect both
patient the functioning of implant - Engineered biological tissue can cause adverse
immune reaction - Still empirical
20Solution? Surface Engineering
- Biorecognisable implant surface
- Designing templates with cell-adhesion molecules
- Micro- and nano-texturing of surface
- Porous Structures Why?
- Drug-eluting surfaces
21Functional Tissue Engineering
- Engineering Living Tissue on Synthetic Scaffolds
- Scaffolds porous, biodegradable, mimic the
extracellular matrix - Several parameters at play ?
- Role of Mechanical Engineering Develop
mathematical models to describe tissue growth on
scaffolds through these parameters - Whats the difference between tissue engineering
and functional tissue engineering?
Boccafoschi, F et al. Biomaterials 26 (2005)
74107417
22Interface with Excitable Tissue Toward
Neuromuscular Prosthetics
- Excitable TissueNerve, Muscle
- Bioelectronic Devices are either stimulate/record
biosignals (or both) - Electronic Implant consists of
- Power Source
- Controller
- Stimulator
- Electrode
- Used in a wide range of pathologies spinal cord
injuries, parkinsons disease, epilepsy, stroke
etc. - Nerve-electrode interface remains the weakest
link - Study of bioelectric phenomena crucial to
developing biocompatible electronic implants.
23Notions in Bioelectricity
- Equivalent circuits used to model intefacial/
bioelectric phenomena - Impedance Analysis used to calculate parameters
affecting charge transfer from device-tissue - Capacitance
- Inductance
- Resistance
- Models derived used to design medical
instruments, biosensors and other bionic devices
Zhu, F., Leonard,.E Levin,. N Physiol. Meas. 26
(2005) S133S143
24Wrap-up Points to Remember
- Highly multidisciplinary field drawing in on
chemistry, biology, physiology, mechanics,
electronics . - Unlike the man-made world, Nature SEAMLESSLY
integrates different components and functions
into a working unit. - Biological materials vastly differ from man-made
materials and that has to bet aken into account
when designing implants - Bionic Implants emerge ONLY in response to a
clinical PULL (need) - Bionic Implants to be designed with Clinical and
Market Realities in mind. - Role of Mechanical Engineer Interfacing with
multiple disciplines, interacting with multiple
professionals.
25Carbon Nanotube Sheets for use as Artificial
Muscles Discussion Questions
- Differing requirements for robotic vs. prosthetic
applications - What are the advantages of carbon nanotubes?
- What are their drawbacks?
- Predict behaviour in-vivo
- Follow-up to this work?