Medtech

We are a horizontal research team that aims to strengthen IME’s leadership position in Microelectronics by innovating on our technologies for applications in MedTech and Consumer Electronics.
We innovate and create customized solutions for MedTech applications via Ion sensing (sweat detection, IV blood glucose monitoring, multiple ions sensing), Molecular sensing (novel ovulation tracking), Tactile sensing (extravasation injury detection patch, sensorized catheters, hearing aid model) and Contactless sensing (imaging using ultrasonic and IR sensors).

• ISO13485 certified Lab

Our group offers comprehensive solutions from conceptualization of ideas to prototyping. We design and simulate the mechanical and electrical models to study the device’s feasibility using SOLIDWORKS, Ansys and COMSOL. The functionalities of the developed devices are characterized and prototyped in our ISO13485 certificated labs.

Development of Integrated Thermistor Sensor and Heating Electrode for Renal Denervation Procedure

Hypertension is a growing worldwide issue. Patients whom blood pressure level were unable to be brought under control despite the usage of three or more medication is known as resistant hypertension. Resistant hypertension increased the risk of patients developing adverse cardiovascular disease as compared to patients with controlled high blood pressure. The current treatment for resistant hypertension includes minimally invasive catheter based renal denervation procedure. However, there is no procedural endpoint of the ablation of the renal nerve for this renal denervation procedure. In this work, an integrated thermistor sensor with a heating electrode was developed for monitoring of the ablation temperature during the procedure. Thus ensuring proper ablation of the nerve, reducing the risk of damaging the renal nerve and increasing the success rate of the procedure. Bench-top characterization on thermistor resistance output with respect to temperature change and ex-vivo testing on RF ablation using the integrated sensor were performed. Testing result were presented in the paper. An average of 15kohm resistance change (ΔR) in thermistor sensing element from temperature range of 25oC to 90oC. For RF power of 1 W, the ablation scarring size on the tissue was approximately 2mm (length and width) with a depth of 2.5mm depth.
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Novel Conformal Skin Patch with Embedded Thin-Film Electrodes for Early Detection of Extravasation

Extravasation is a complication of intravenous (IV) cannulation in which vesicant drugs leak from a vein into the surrounding subcutaneous tissue. The severity of extravasation depends on the type, concentration, and volume of drugs that accumulate in the subcutaneous tissue. Rapid detection of extravasation can facilitate prompt medical intervention, minimizing tissue damage,
and preventing adverse events. In this study, we present two portable sensor patches, namely gold and carbon-based sensing patches, for early detection of extravasation. The gold-based sensor patch detected extravasated fluid of volume as low as 2 mL in in vivo animal models and human clinical trials; the patch exhibited a resistance change of 41%. The carbon-based sensor patch exhibited a resistance change of 51% for 2 mL of extravasated fluid, and fabrication throughput and cost effectiveness are superior for this patch compared with the gold-based sensing patch.

Development of Low-Contact-Impedance Dry Electrodes for Electroencephalogram Signal Acquisition

Dry electroencephalogram (EEG) systems have a short set-up time and require limited skin preparation. However, they tend to require strong electrode-to-skin contact. In this study, dry EEG electrodes with low contact impedance (<150 kΩ) were fabricated by partially embedding a polyimide flexible printed circuit board (FPCB) in polydimethylsiloxane and then casting them in a sensor mold with six symmetrical legs or bumps. Silver–silver chloride paste was used at the exposed tip of each leg or bump that must touch the skin. The use of an FPCB enabled the fabricated electrodes to maintain steady impedance. Two types of dry electrodes were fabricated: flat-disk electrodes for skin with limited hair and multilegged electrodes for common use and for areas with thick hair. Impedance testing was conducted with and without a custom head cap according to the standard 10–20 electrode arrangement. The experimental results indicated that the fabricated electrodes exhibited impedance values between 65 and 120 kΩ. The brain wave patterns acquired with these electrodes were comparable to those acquired using conventional wet electrodes. The fabricated EEG electrodes passed the primary skin irritation tests based on the ISO 10993-10:2010 protocol and the cytotoxicity tests based on the ISO 10993-5:2009 protocol.

Solid state ion selective pH sensor

pH sensors are widely used in various applications such as agriculture, wastewater monitoring, and biomedical engineering. Solid-state ion-selective electrodes (ISEs) have been developed to enable the miniaturization of pH sensors. This paper evaluated the pH sensing electrodes based on hydrogen ionophores or pH-sensitive emeraldine-polyaniline. A miniaturized leak-free reference electrode was integrated with pH sensing electrodes. A multiple-channel electromotive force recording unit was built to facilitate the measurement of multiple ISEs. The sensitivity and dynamic range were assessed using the pH solutions from pH 1.3 to pH 10. The conductance and capacitance of different ISEs were measured and compared. We evaluated the longevity and stability of the emeraldine-polyaniline-based pH sensor, and the drifting was less than 4 mV/day.
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3D probe array integrated with a front-end 100-channel neural recording ASIC

Brain–machine interface technology can improve the lives of spinal cord injury victims and amputees. A neural interface system, consisting of a 3D probe array and a custom low-power (1mW) 100-channel (100-ch) neural recording application-specific integrated circuit (ASIC), was designed and implemented to monitor neural activity. In this study, a microassembly 3D probe array method using a novel lead transfer technique was proposed to overcome the bonding plane mismatch encountered during orthogonal assembly. The proposed lead transfer technique can be completed using standard micromachining and packaging processes. The ASIC can be stacking-integrated with the probe array, minimizing the form factor of the assembled module. To minimize trauma to brain cells, the profile of the integrated probe array was controlled within 730 μm. The average impedance of the assembled probe was approximately 0.55 MΩ at 1 kHz. To verify the functionality of the integrated neural probe array, bench-top signal acquisitions were performed and discussed.
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Multi-Cell Array of Nanogap Electrodes for Label-free Detection of Biomolecules

A silicon-nanowire-based Coulter counter has been designed and fabricated for particle/cell enumeration. The silicon nanowire was fabricated in a fully complementary metal-oxide-semiconductor (CMOS)-compatible process and used as a field effect transistor (FET) device. The Coulter counter device worked on the principle of potential change detection introduced by the passing of microparticles/cells through a sensing channel. Device uniformity was confirmed by scanning electron microscopy and transmission electron microscopy. Current-voltage measurement showed the high sensitivity of the nanowire FET device to the surface potential change. The results revealed that the silicon-nanowire-based Coulter counter can differentiate polystyrene beads with 8 and 15 μm diameters. Michigan Cancer Foundation-7 (MCF-7) cells have been successfully counted to validate the device. A fully CMOS-compatible fabrication process can help device integration and facilitate the development of sensor arrays for high throughput applications. With appropriate sample preparation steps, it is also possible to expand the work to applications such as rare-cells detection.

Medtech

Tactile Sensing Platform

Ions sensing Platform

Molecular sensing Platform

Medtech

Tactile Sensing Platform

Ions sensing Platform

Molecular sensing Platform

A*STAR celebrates International Women's Day