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biomedical engineering - Coggle Diagram
biomedical engineering
Regulatory affairs
Technical file
Device master record
definition; Collection of documents specifying a device and the processes required for its manufactures
Overall manufacturing and inspection plan
Device history file
definition; full description of the design process including all key documents and project management records
Design output; the information defining the finishing device, product specifications, process requirements, and labelling.
Validation; Evidence that the design meets user requirements (i.e works in real world), done by clinical evaluation
Verification; Evidence that the design output meets the input requirements, done by testing or inspections, use standards.
Design input; Information drawn from users, risk management and other sources which define what the device must do and be. Specific and measurable
Start as general requirements; clinically relevant specificity,etc.
Need to be converted into measurable specifics; shelf life, compliancy, etc.
Can be verified by inspection or testing; obtain IEC 60601-1 test certificate from accredited lab
Design specifications, summary of testing reports and certifications, clinical evaluation, risk analysis, essential requirements check list, product documentation, labels and manuals, etc.
Clinical trials
TGA approval
Classes of medical devices
Class IIa
Class IIb
Class I
Class III
Case studies
Software (fitbit)
Software must allow healthcare professionals to override, data written in simple terms so that clinicians can understand.
Quality system standards for medical devices are ISO13485
Software standards need to be updated as the software is updated from 1.0 to 2.0 as it is perceived as a whole new product.
Postmarket case study; fatigue failure of heart valve
Registries keep records of the doctor, patient, hospital, diagnosis and device in case of failure or complications.
Two out of many other device models caused complications in patients after surgery (i.e postmarket).
Condom water bombs
the product gets damaged due to heat during travel across the Mexican desert
Postmarket failures are always newsworthy, and a media and communications plan needs to be in place to prevent defamation.
Anatomy and physiology
Bones
Types of bones
Carpals (short bone)
Humerus (long bone)
Frontal bone (flat bone)
Vertebra (irregular bone)
Patella (sesamoid bone)
Joints
Cartilaginous Joints - Slight movement
Synovial Joints - free movement
Fibrous joints - No movement
Joint cavity with synovial fluid
Joint capsule
Articular cartilage
Smooth surface reduces friction at points of articulation
Special biomechanical properties stabilize and protect the joint and the interior bone tissue
Intervertebral joints
Intervertebral symphyses (intervertebral discs: not synovial!)
Facet joints
Intervertebral disks
Separates vertebral bodies
Consists of: • Annulus fibrosus • Nucleus pulposus, as vertebral column moves: • Nucleus pulposus shifts • Disc shape conforms to motion
Pads of fibrocartilage
Bone composition
organic phase (If collagen removed, bone is too brittle)
mineral phase (If mineral removed, bone is too bendable)
water
Muscular system
Cardiovascular muscle system
Structure
Pulmonary artery
Pulmonary vein
Aorta
Left atrium
Aortic valve
Superior vena cava
Pulmoary vein
Right atrium
inferior vena cava
Left ventricle
Right ventricle
Triscupid valve
Mitral valve
Layers of the heart
Myocardium
Endocardium
Visceral pericardium
Skeletal muscle system
Histology
Characteristics
voluntary
strong contractions
striated, long, cylindrical multinucleate cells
may be 'slow' or 'fast', not rhythmic
Nervous System
Spinal cord
Neurons
Motor neuron
Interneuron
Sensory neuron
Parts of a neuron
Soma (cell body)
Membrane potentials
Voltage-gated channels; opens in response to changed in transmembrane potential, excitable membrane such as axons,etc.
Mechanically gated; opens in response to membrane distortion, found in sensory receptors (touch, pressure, vibrations,etc)
Chemically gated channels; opens in response to chemicals (eg. neurotransmitters), found on neuron cell bodies and dendrites.
Step 2: Activation of Na+ (sodium) channels
Rapid depolarisation
Na+ ions rush into cytoplasm
Inner membrane changes from negative to positive
Can propagate across an excitable membrane
Step 3: Inactivation of Na+ channels and activation of K+ channels
Occurs at +30 mV
Inactivation gates close (Na+ channel inactivation)
K+ channels open
Repolarization begins
Step 1: Depolarisation to threshold
Graded depolarisations that collect at the axon hillock, large enough to change the resting potential ( -70mV) to the threshold ( -60 to -55mV) levels
Opens the voltage-gated sodium channels
Step 4: Return to normal permeability
K+ channels begin to close when membrane reaches normal resting potential ( –70 mV)
K+ channels finish closing when the membrane is hyperpolarized to -90mV
Transmembrane potential returns to resting level, marking the end of the action potential
Myelin and myelin sheath
Dendrites
Axon hillock and Axons
Axon terminals
Brain
Medical imaging
Tomography
Positron emission tomography
Motion correction
Single photon emission computed tomography
.
Implications
Degraded image quality
Ghosting
Increased noise
Streaking
Loss of contrast
Blurring
loss of resolution
Motion Corrections/compensation
Image registration (alignment)
Excluding corrupted data
Gating (grouping data collected at regular time intervals)
Event by event based compensatiion
Preventions
Invasive forcible restraint (eg. stereotactic frame or other surgical fixation)
Passive restaint (for positioning and comfort)
Non-invasive forcible restraint (drugs/anaesethia, paralysis, thermo-plastic mask)
Problems with prevention methods; add risk time and cost, hard to prevent or eliminate with passive methods...
Computer tomography
Ethical considerations
Virtue ethics
Outcomes are less important than the morality and character, motivated by the virtues of perseverance, courage, compassion and self-regard
Duty ethics
The rightness or wrongness of an action is adjudicated according to a set of subjective rules
Utalitarianism
Maximising human happiness (hedon), minimising human suffering (dolors)
Rights ethics
upholds the rights of all parties to the decision
Consequences not considered, the focus is on the process used for decision making
Ethical egoism
Focus on self and own interests
Engineers Australia code of ethics
3) To exercise leadership
To promote sustainability
2) To practice competently
1) To demonstrate integrity
Tissue engineering and biomaterials
Mechanobiology and tissue engineering
Tissue engineering
Biomolecules
Growth factors for cell growth and function
Factors promoting vascularisation
Molecules that attract the cell type(s) of interest
Cells in tissue engineering
Living part of tissue
Produces protein and provides the function of cells
Gives tissue reparative properties
Mechanobiology
Mechanobiology has emerged as a discipline dedicated to the study of the effects of mechanical forces and geometry on cell growth, motility and functionality.
Biomechanical cues
Differentiation
mechanical forces regulate cell division
Substrate stiffness
Proliferation
Mechanical signalling
Migration
Cell stretch
Apoptosis
Engineering strategies
Using hydrogels as platforms to mimic the cell microenvironment with tailorable physical cues
Stem cell differentiation
Substrate rigidity was adjusted by changing the polyacrylamide crosslinking density
Mechanomics
Mechanics as an ever present physical dimension of cell and developmental biology
role in morphogenesis and tissue patterning
physical and chemical cues
additive manufacturing
3D bioprinting with biological molecules and cells
Maintainance of shape
Cell friendly
Printability
Pathophysiology - how the body works when something is wrong; physiological processes associated with disease or injury
biomaterials
types and features
Synthetic
Poly (vinyl alcohol)
Poly (capro lactone)
Poly (ethylene glycol)
Advantages; tailorable, physical and mechanical properties, surface modification, biodegradable, easy to fabricate
Disadvantages; leachable toxic compounds, wear and breakdown, difficult to sterilize.
Bioceramic materials
Advantages; corrosion resistance, bioactive/inert, easy to sterilize
Disadvantages; mechanical properties are compromised, not easy to fabricate
Metallic biomaterials
Advantages; high strength, wear resistance, easy to sterilize
Disadvantages; corrosion metal ion toxicity
Natural
Silk
Gelatin
Collagen
Biomaterials form and function
Bioinstructive
Biodegradable
Biomimetic
Bioerodible
Biofunctional
Bioinert
Bioactive
Rejection of biomaterials
Foreign body reaction
Normal wound repair
Decellularized biomaterials
Composed of native ECM molecules. Biodegradable and biocompatible after decellularization
Nanomaterials in medicine
Tissue
Enhanced permeability and retention effect
Primarily; conjugating (adding) therapeutic drugs, genes, or fluorescent molecules (depending on intended function)
Functionalizing/conjugating i.e attaching of decorating, therapeutic drugs, genes or flurescent molecules
Biomolecules; molecules produced by cells such as proteins, nucleic acid/amino acid sequences, carbohydrates, lipids that govern one or more biological activity or function. Keep in mind that different cells, different tissues, and different environments have unique ‘biomolecular profile’ that makes them what they are.
targeted drug/biomolecule/cell delivery vs systemic delivery
drug is distributed through the bloodstream throughout the whole body, passive vs active,
Nanoparticles can act as a drug releasing station, go to where it needs to go, release consistently allowing controlled drug delivery
Theranostics.- a portmanteau of therapy and diagnostics. allows a single NP to both detect and affect at the same time
Nano gold; Gold NP interaction with light strongly dictated by; medium in which the nanoparticle is in- the dielectric properties of the medium, size, shape
White incident light comes in towards the metal NP
The oscillating electromagnetic field of the light interacts with the free surface electrons
The free surface electrons then oscillate/resonate, subsequently resulting in the oscillation of charge (i.e surface plasmon resonance (SPR))
The SPR interacts with the incident light simultaenously
SPR+ incident light interaction leads to absorption of certain frequencies/wavelengths and reflection of others
Generates colour.
Biosensing applications
in vitro
in vivo
Cell
lock and key; protein and substrate model
interact with the cell compartments/organelles
Cells are influenced by the environment
surface chemistry
surrounding soluble factors
physical surface properties (stiffness, topography0
can exploit any physical nanosized gaps in the body that may let NP though
Intrinsic therapeutic efficacy (targeted cell killing)
Attach no drugs to NP, doesn't kill cells on its own. can be triggered non-invasively
nanoscale (10^-9)
nanoparticles larger than 200nm more likely to activate the complement protein system (i.e more immune response)
Fluid dynamics and microfluidics
Microfluidic devices are small devices with many chemical functions in a small chip
Microfluidic geometry
Optically transparent
Biocompatible material
Small amount of reagent necessary (nano- or pico- litre)
Lab on chip - eg. microreactor in a droplet
Low reynolds number; laminar (viscous) flow:
Any geometry
High throughput
Flow rate
Turbulent flow
unsteady vortices appear on many scales and interact with each other
Laminar flow
fluid flows in parallel layers, with no disruption between the layers
Continuous flow
T- Junction
Flow Focusing
Droplet manipulation
Multiple emulsions
Droplet microfluidics
2 more items...
Capillary
Segmented flow
Mass diffusion; brownian motion
particles observed to undergo random motion
Human on a chip?
With the help of microfluidics and fluid dynamics, we can understand responses to drugs before adding them to the system and prevent side effects helping create; a patient on a chip
Symmetrical valve stiffness
Asymmetrical valve stiffness
Research areas
Whether Piezo1 is the long-sought-after sensor to differentiate good vs bad force for thrombosis?
Unique biomechanical nanotools for mechanosensing
Mechanosensitive Ion channel
Current anti-platelet drugs and market values
Targeting platelet mechanosensing
Mechano medicine in vivo
Humanised vessel on chip for anti-thrombotic studies
Innovation in disability
Cerebral palsy
Neonatal intensive care
Resuscitation monitoring, physiological signal analysis, music EEG, 3D printing virtual twin mannikins
Brain computer interface
reduce re-calibration
increase privacy
direct eye communication
Context dependent (computer vision)
Implants
Calculation; vascular resistance
circulatory system consists of different types of vessels in series with different resistances to flow
Calculation; cardiovascular system
human circulatory system consists of two circuits; pulmonary circulation which carries blood through the lungs, and systemic circulation which carries blood to the organs
Sleep-related medical devices
motivation
Sleep apnoea is a disorder characterised by interruptions of breathing during sleep.
The obstruction events can occur hundreds of times in a night
Increased accident levels due to sleepiness
Sleep cycle
dreaming usually occurs during REM (25%)
slow-wave sleep or deep sleep (25%)
light sleep (45%)
transition between wake and sleep, easy to wake from, may not be aware asleep (5%)
Normal sleep - hypnogram
method of visualising and summarising the pattern of sleep cycles and shifts between sleep stages
Sleep apnoea
Loud persistent snoring
Witnessed pauses in breathing
Choking or gasping for air
Restless sleep
Frequent visits to the bathroom
Early morning headaches
Daytime sleepiness
Poor concentration
Irritability
Falling sleep during routine activities
Measuring sleep quality
self report (stylised questions)
self report (sleep diaries)
objective measures
PSG -Sleep lab
Air flow - home sleep test
Actimetry
Mattress pad
EEG Band
Sleep diagnosing devices
ApneaLink Air
SleepScount/SleepView
Somte PSG
Therapy monitoring
Wearables/smart phone apps
Smart phone apps (tracker-less)
ECG derived respiration (EDR)
ECG-based automated system for apnoea detection
Extracting maximum information from a sensor (ECG)
Biomanufacturing
Control of non-conforming product
Need to figure out what the mistake is and remove it from product
Handling, storage, packaging, preservation and delivery
Safe packaging as not to ruin the product
Needs to work in all environments
Inspection and test status
Control of quality records
Keep records of everything including the failed versions of products
Corrective and preventative action
If there is health repurcussions from product it needs to be modified
Internal quality audits
Control of inspection, measuring and test equipment
Training
Inspection and testing
Servicing
Process control
Need to do everything the same way everytime, manufacturing work instructions
Statistical techniques
Prove the results and impact of product with statistics
Product identification and traceability
Need to document to know what the loose ends are
Control of customer-supplied product
Motidification of products from customers
Purchasing
Deal with purchasing agents
Document and data control
Documented with precision and organised data control to know where it is
Design control
If design is changed the product functionality could change, thus it needs to be noted
Contract
Reviews conducted by a professional and not just any one
Quality system
Write things down to prevent mistakes, to remember what to do and what not to do, learn from the mistakes
Management responsibility
Someone is responsible for the mistakes
Industry and post-graduate options in biomedical engineering
Postgraduate
Chronic wounds in diabetes
Fluorescent dye used for carbon nanoparticles
myoelectric sensors for rehabilitative purposes
Bionic eye research
Industry
Corin
Johnson and Johnson
Redmed
Cochlear
B Braun