A Wireless, Implantable Visceral Nerve Sensing and Stimulation Platform with Electrode Impedance Monitoring

SIGNIFICANCEThe long term impact of stimulation upon visceral organ function remain unknown in many diseasesas acute tethered experiments are confounded by the influence of anesthesia and abnormal patterns of food intake and sleepAnimal handling stressloss of animals from damage to electrode hardware and connectorsand motion artifacts preclude tethered configurations as a viable alternative for long term studiesRecentmeetings by SPARCbioelectronics medicineand DARPA researchers exemplified a lack of ability to perform long term continuous stimulation or recordings in small animalsNew fully implantable devices are needed to extend these acute and short term results from tethered animals to long term studies and to justify costly therapeutic validation in large animal modelsThough the concept of a `closed loop wireless implantable deviceis not novela wireless device appropriate for stimulationrecordingand impedance monitoring from small visceral nerves in behaving small animals at this scale is highly innovativeUntethered and freely behaving operation for multiple animal body weights and implant locations in the rat pose significant miniaturizationpowerand heating constraintsStimulation dosing studies for multiple nerve targetsfor examplerequire programmable bi phasic current amplitudes up tomAV compliancevariable pulse widthskHz frequency blocking waveformsand electroneurogramENGrecordingseach requires a different operating powerFurthermoreENG recordings require ax lower noise than cortical recordingsare difficult even with precision benchtop systemsand noise reduction techniques are too power hungry for implantable operationAn innovative wireless power receiver approach is needed to accommodate the power consumption of a multi functional circuitwhile also not heating the implantable device surface rtCand dynamically adapting to variable animal orientationLead wire tethering forces on small nerves electrodes must also be reducedINNOVATIONWe will develop a fully implantable stimulationrecordingblockingand impedance monitoring fully implantable devicexxmmfor rtday continuous operation from wireless powerAn innovative and adaptive mode switching wireless power receiver is proposed which uses temperature feedback to alternate between resonant and non resonant coupling modesto eliminate device heating and to maximize available power for stimulation and recordingA stretchablemicro helical lead wire is proposed to reduce tethering forces between our novel external urethral sphincterEUSelectrode and commercial cuff electrodeA novel arrayable and networkconnected telemetry base station scalable to a vivariumis proposed to enable a single computer to stimulate and monitorfreely behaving animals over a networkOUTCOMESThis SBIR Phaseproposes to develop and commercialize the `Stim Senseuntethered system which includesan implantable device for bi phasic stimulationENG and EMG recordingsbi phasic kHz blockingand impedance monitoring for freely moving and stress free animals in a vivarium andvalidation of the system in a hybrid autonomic interface in overactive bladderThese milestones will enable a focused Phaseeffort to remotely stimulate and monitor multiple cohorts of dozens of animals