Enver G. Kilinc

A System for Wireless Power Transfer of Micro-Systems In-Vivo Implantable in Freely Moving Animals

A system for wireless power transfer of micro-systems in-vivo implantable in small animals is presented. The described solution uses a servo-controlled transmitter moved under the animal moving space. The solution minimizes the power irradiation while enabling animal speeds up to 30 cm/s. An x-y movable magnetic coil transmits the required power with a level able to keep constant the received energy. A permanent magnet on board of the implantable micro-system and an array of magnetic sensors form a coil tracking system capable of an alignment accuracy as good as 1 cm. The power is transferred over the optimized remote powering link at 13.56 MHz. The received ac signal is converted to dc voltage with a passive full-wave integrated rectifier and the voltage regulator supplies 1.8 V for the implantable sensor system. Experimental measurement on a complete prototype verifies the system performance.

Design and optimization of inductive power transmission for implantable sensor system

This paper presents a methodology to design and to optimize inductive power link for biomedical applications. The importance of the operation frequency on the application is expressed. A model of inductive link is presented. The dimensions of the coils are compatible with the size of a mouse and the mouse cage. The simulation results are in good agreement with the analysis.

Full fabrication and packaging of an implantable multi-panel device for monitoring of metabolites in small animals.

In this work, we show the realization of a fully-implantable device for monitoring free-moving small animals. The device integrates a microfabricated sensing platform, a coil for power and data transmission and two custom designed integrated circuits. The device is intended to be implanted in mice, free to move in a cage, to monitor the concentration of metabolites. We show the system level design of each block of the device, and we present the fabrication of the passive sensing platform and its employment for the electrochemical detection of endogenous and exogenous metabolites. Moreover, we describe the assembly of the device to test the biocompatibility of the materials used for the microfabrication. To ensure biocompatibility, an epoxy enhanced polyurethane membrane was used to cover the device. We proved through an in-vitro characterization that the membrane was capable to retain enzyme activity up to 35 days. After 30 days of implant in mice, in-vivo experiments proved that the membrane promotes the integration of the sensor with the surrounding tissue, as demonstrated by the low inflammation level at the implant site.

A Remotely Powered Implantable Biomedical System With Location Detector

An universal remote powering and communication system is presented for the implantable medical devices. The system be interfaced with different sensors or actuators. A mobile external unit controls the operation of the implantable chip and reads the sensors data. A locator system is proposed to align the mobile unit with the implant unit for the efficient magnetic power transfer. The location of the implant is detected with 6 mm resolution from the rectified voltage level at the implanted side. The rectified voltage level is fedback to the mobile unit to adjust the magnetic field strength and maximize the efficiency of the remote powering system. The sensors data are transmitted by using a free running oscillator modulated with on-off key scheme. To tolerate large data carrier drifts, a custom designed receiver is implemented for the mobile unit. The circuits have been fabricated in 0.18 um CMOS technology. The remote powering link is optimized to deliver power at 13.56 MHz. On chip voltage regulator creates 1.8 V from a 0.9 V reference voltage to supply the sensor/actuator blocks. The implantable chip dissipates 595 μW and requires 1.48 V for start up.

Intelligent cage for remotely powered freely moving animal telemetry systems

An intelligent power feedback design for remotely powered freely moving animal telemetry systems is described. The system uses an optimized wireless power transmission that utilizes multiple transceiver coils. An intelligent mouse cage with controller unit of the feedback system are proposed. System description, experimental setup and measurements of the remotely powered implantable monitoring system are presented.

An implantable bio-micro-system for drug monitoring

Multi-target and continuous monitoring by wireless implantable devices is of increasing interest for personalized therapy. In this work an implantable system is presented which is capable of measuring different drugs with Cyclic Voltammetry (CV) method. The wireless microsystem consists of four modules, namely (i) The inductive coil; (ii) Power management IC; (iii) Readout and control IC; (iv) Biosensor array. The power management IC provides 1.8 V with as high as 2 mW power for the readout IC. The configurable readout IC is able to control the biosensor array and measure the sensor current in CV method. CV experiments performed with this microsystem well agree with a commercial equipment for two well known anti-cancer drugs, Etoposide and Mitoxantrone, detection.

A System for Wireless Power Transfer and Data Communication of Long-Term Bio-Monitoring

A system for wireless power transfer and data communication of implantable bio-monitoring systems is presented. The proposed solution uses a servo-controlled power transmitter moved under the animal moving space. An x-y movable magnetic coil transmits the required power with a level able to keep constant the received energy by the bio-sensor system. The power is transferred via the optimized remote powering link at 13.56 MHz. The received ac signal is converted to dc voltage with a passive full-wave integrated rectifier and the voltage regulator supplies 1.8 V for the implantable sensor system. The sensor control and readout circuit measures the current on the bio-sensors and transmit the data to the transmitter. The sensor data are transmitted to an external reader by a low-power OOK transmitter and received by a custom designed receiver at 869 MHz. The results are shown in a tablet computer in real time continuously. The long-term characterization of the implantable system is verified by a fully bio-compatible packaged implant with 30 days measurement. A complete prototype is also presented to prove the overall system performance with the experimental in vitro measurement.

Remotely powered implantable heart monitoring system for freely moving animals

This paper presents a remotely powered implantable heart monitoring system for freely moving animals. The system measures the blood pressure in the left ventricle of the heart and transmits the data to a database unit. The implanted unit is remotely powered over 25 mm at 8 MHz and has autonomous power control system for changing received power levels due to the moving animal. The blood pressure is measured by a piezoresistive sensor die. The data is transmitted by a OOK modulated transmitter at 868 MHz. The system is realized by using discrete components which are available on the market. The overall size of the implanted unit is 26×13×5.5 mm and the overall power consumption is around 7 mW. Experimental results show the effectiveness of the implantable monitoring system.

3.2 mW ultrasonic LSK modulator for uplink communication in deep implanted medical devices

The wireless body area network (WBAN) includes up to ten sensor nodes and an external control unit to synchronize the wireless power transfer and communication. A battery operated sensor node is designed using discrete components and tested on standard FR4 substrate. The board dimensions are 2.7 × 4.9 cm2 which fits inside the Kinetra neurostimulator casing provided by Medtronic, wherein a six elements array transducer (5 × 10 mm2) is glued. The transponder power consumption is 3.2 mW when transmitting data towards the control unit, and only 49 μW when in sleep mode.

FoM to compare the effect of ASK based communications on remotely powered systems

This paper presents a Figure-of-Merit to compare the remotely powered communication systems. The important parameters for remote powering and also communication are presented. The effect of ASK based communications on remote powering performance is analyzed by representing the challenges of power transfer during data transmission. This Figure-of-Merit is introduced to compare different modulation types in terms of powering and communication performances.