Quiz 3 (Lecture 9-11) (No FET) Flashcards
Stimmulation and recording
both use eletronic chips to get data
Neuron
acts as controler for the body sending eletrical signals for all essential functions
Brain- Machine interface
brain- electrochemcial signals(ionic)
Computer- eletronic signals (electrons)
Non invasive neural prosthetics
Limitations- not able to directly interact with CNS
EEG
GSR
fMRI
Invasive implantable prosthetics
- techniques- directly targeting singal neurons & collecting local field potentials
- limitations= material biocompatability potential causing gliosis
Material biocompatablility 3 measures
A) contruction materials
- Toxicity - smaller dimensions- sharper (reduces tissue response
B) Cell morphology
C) viability
Issues with implantation
can cause glial scar response(limit damage by reducing size and increasing sharpness)
Living cell Surface Interaction
-many cells must attach to an external surface to avoid apoptosis
- cells ability to stretch and attach have a greater viability then those that are not able to
Ionic- Eletronic Interface
- nerve cell is surrounded by eletrically insulating core of lipid
- allows for neuron-semiconductor bioeletric applications to be possible through communication of brain(ionic) and technology (eletronic)
Planar Eletrical Core Coat Conductor
- cell adhesion is faciliteted by protein molecules protruding from cell membrane (the proteins stabilize the cleft)
- Cell-Silicon Junction forms the the planar eletrical core conductor
Steps of planar eltrical core coat conductor formation
1st step- Neuroeltric interfacing - RECORDING= activity of neuron leads to ionic & displacement currents
STIMULATION= voltage is applied to get displacement current
2nd step Detect TEP-
RECORDING= TEP induced by neuron is probed by the FET
STIMULATION= TEP induced by the chip is probed by the potential acorss the ion chanels in the neronal membrane
Coupling of Neurons & Chips
TEP in the cleft facilitates coupling
Neuron- silicon integration
NEURONAL NET is used to see how far a signal can travel or for testing cultured neurons
- MICROELECTRONICS- used when there is a damaged piece in between transistor and stimulator
silicon neuron junction polarization and stimulation
polarization- allows for direct coupling between electronic and ionic signals
stimulation - involves capacitativly stimulating the neuron
both relate to the cleft region where the current resides between the neuron and the chip
Important properties of Nanomaterials
-distribution of electronic levels in optical devices
- High surface area to volume ration
- Size is compatible with biopolymers
4 things that characterize nanotech
- size
- ability to synthesize new properties
- ability to image, measure, model
- ability to integrate
Metalic Nanoparticals
- improve conductivity and transduction in sensing elements
- can act as catalysts involved in recognition/ transduction processes
Carbon fullerene family
sp2 hybridization has better stability ( graphite)
- graphene is made up of benzene- type hexagonal rings
3 characteristics of CNTs (n&m)
n=m metallic arm chair
n-m= factor of 3: metallic zigzag or chiral
n-m/= factor of 3 semiconducting zigzag or chiral
CNT application in chem sensors
-suitable as molecular wires in electrochemical sensors
- integrated using physcial adsorption, covalent binding or incorperation
implications of nanotech in biosensing
nanotech enables us to design smaller, less power hungry, more sensitive systems,
- allows for bionanomaterial hybrids (DNA-NP & DNA-CNT)
5 ways to couple
- electrostatic
- streptavidin/biotin
- sulfide bonds - cystein
- amino acid
Discrete V. Integrated
discrete is component by component( arduino/breadboard)
- Integrated is Chips (FET,ISFET)
2 substrates of trandsucers
sensor and actuator
