New Generation of Implant Medical Devices - Fhi...Bob Puers KULeuven ESAT-MICAS 1 Main envisaged...
Transcript of New Generation of Implant Medical Devices - Fhi...Bob Puers KULeuven ESAT-MICAS 1 Main envisaged...
NewGenerationofImplantMedicalDevices
BobPuersKULeuvenESAT-MICAS
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Mainenvisagedlongtermtargetapplications
• Neurology• Electro-corticography electrodeformation• Self-adaptingelectrodenetwork• Reconstructionofmissingbrainconnectivities
• Urology• Theurologicalpacemaker• Sensingthebladder:micro-movements,electricalactivity,pressure
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Neurology
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Toppost.co
Ourquest:thecomfortableimplant
§ Arrayswithresorbablematerials astemporarysupport• Strongenoughduringinsertion• Lowerirritationduringuse
§ Targetuseinlesioncavities• Designforhighmechanicalflexibility• Recordingandstimulationfortherapy
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GeneralAim
• Exploringnewneuralelectrodearrayconcepts• Verylongtermneuralinterfacing• Highresolutionneuralinterfacing
• Basedonflexibleelectronics,advancedpackagingand/orbiofunctionalisation
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Materialselection
• Non-resorbablesensormaterials:• Ptelectrodesandconnectors,PIorparyleneCinsulation• Classicalmaterials,butverythinandfinelypatterned
• Resorbablemateral:Chitosan• Itcanbedissolvedinanacidicenvironment,facilitatingspin-onprocessing
• Goodadhesion• Hashaemostatic andantisepticproperties• Canbeformedintoaporous,fastresorbable form• Degradationratecanbevariedbyalteringthedegreeofdeacetylation
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Fabrication
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Invivotesting
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§ Implantation on meninges ->or under meninges inrats
§ Measure physiological response
Typicalmeasurementofstimulusandphysiologicalresponse
Measure here
~ Stimulate here
Amplitudeofresponseovertime
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!
Whatisnext:Flexiblespiderstructures
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Ourcurrent implanttechnology
• Thin filmpolyimide (7µm)• Developed foruseinbrain lesion cavities• Improved insulation• Ptmetal,orIrox forreduced impedance
• Tested upto1year inrats• Tested ECM/chitosan coating• Recent :Mg/PLGA
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Underdevelopment
• Neutrotropic electrode arrays• Resorbable needle shaped electrode arrays• Highresolution interfacing electronics• Flexibleactivesilicon-based arrays
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NeurotrophicElectrode
• Goal:improvinglong-termreliabilityofintracorticalmicroelectrodes
• Hollowtubeelectrodefilledwithneurotrophicgrowthfactorcontaininghydrogel
• Reducedimmunologicalresponse(glialscarring)
• Guidedneuritesprouting(chemotacticgradientofgrowthfactors)
à nomicromotions/highSNR
à Improvedelectrodelifetime
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Partially resorbable electrode arrays
• Need relatively stiff needle-like structuretoget into thebrain forhigh resolution interfacing
• Carrierdissolves,only bare minimumstays behind• Minimizing chronic damage
• Maininspiration:• Turner• CharlesLieber
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Finalgoalforhigh-res neurointerfacing
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Polyimide electrodes
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• Currently:modest number ofelectrodes (±30),improvewith ASICtoward 1000+ofcorticalelectrodes
• Peripheral nerveelectrodes with magnesium stiffenerforinsertion
Urology
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mammothhospital.org
Evaluationofbladderfunction
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Urodynamicmeasurementsproviderelevantphysiologicalparameters:
Conventionalmethods:IntraluminalpressureFlow/volumemeasurementsCathetercystoscopyEMGsphinctermuscle
Analysis/diagnosistoolNonewinsights
Understandingthebladderfunction
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Contractile activity in the bladder
Micturition contraction
Central Nervous System:
- Inhibitory mechanisms
- Excitatory mechanisms
Autonomous activity
Localized contractions during
filling phase.“Pacemaker cells”
Non-micturition contractions
Urinary urgency?
BladderDetrusor
Sphyncter
Pelvic floor
Earlierresearchworkinourgroup
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- capacitivesensing- introducingflex- separatecircuit- inductivepowering
- linkingwithstimulator- towardstheultimateurologicpacemaker
Interestingphenomenaobserved
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AfullyimplantableMEMSsystem
• Multiplelocations:• “Star”shapeddevice• Wraparoundbladder
• Submucosalplacement• Protectionandfixation
• Bladderstretching(upto100%)• Flexiblesubstrate• Structuralstretchability
• Modulardevice:• Sensorsystem:onbladder• Power&communication:subcutaneous
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• Central node• 1 accelerometer• 1 abdominal reference
pressure sensor• 2 microcontrollers
• 3 distal end nodes• 1 accelerometer• 1 bladder pressure
sensor
AfullyimplantableMEMSsystem
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Conclusions
• Fullyimplantablesystemforbladdermonitoring• Proofofconceptonrats/pigcadaver• Testedandvalidatedinvitro• Dummyimplantedinvivo
• Biocompatiblepackaging• Allowsmeasuringpigvoidingbehaviorinawake,naturalstate• Autonomyuptoseveralweeks,dependingonusage
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Finally,whatisourmission?
• Researchtotakemostoutof:• Polymers• 3Dmicro-fabrication&interconnects
• Hybridassembly• Packagingmaterialsforimplants
• Flexible&Stretchable• Soft,jelly-likebehavior• Bioresorbable materials
• Focusonimplant-humaninterface• Lowpowerelectronics&communication
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AnneMarieCernoch’sartistimpression:“Electro-Gelly”
Acknowledments
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• FrederikCeyssens• LuigiBrancato• JohanCoosemans• BramLips• DriesKil• MarkoBakula• MichelDeCooman
• FWO,EC,IWT,ERC,KULeuven