A Comparative Study of Si3N4 and Al2O3 as Dielectric Materials for Pre-Charged Collapse-Mode CMUTs

Capacitive Micromachined Ultrasound Transducers (CMUTs) have many advantages compared to other ultrasonic transducer technologies, especially for implantable devices. However, they require a high bias voltage for efficient operation. To eliminate the need for an external bias voltage, a charge storage layer can be embedded in the dielectric....

Phase Distribution Efficiency of cm-Scale Ultrasonically Powered Receivers

In the domain of ultrasonically powered biomedical implants, there is an increasing interest in cm-scale ultrasonic receivers (RX). However, when a single-element transducer is used as the RX transducer, an uneven phase distribution across the RX area can significantly reduce the harvestable power. In this paper, we investigate the impact of...

An Ultrasonically Powered System Using an AlN PMUT Receiver for Delivering Instantaneous mW-Range DC Power to Biomedical Implants

Aluminum Nitride (AlN) Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) are gaining interest for biomedical implant power due to biocompatibility and lowtemperature processing. However, due to the low piezoelectric coefficient of AlN PMUTs, storage capacitors are often used to accumulate ultrasonic power transferred over an extended...

Focused ultrasound neuromodulation on a multiwell MEA

Background<br/>Microelectrode arrays (MEA) enable the measurement and stimulation of the electrical activity of cultured cells. The integration of other neuromodulation methods will significantly enhance the application range of MEAs to study their effects on neurons. A neuromodulation method that is recently gaining more attention is focused...

Monolithic integration of a smart temperature sensor on a modular silicon-based organ-on-a-chip device

One of the many applications of organ-on-a-chip (OOC) technology is the study of biological processes in human induced pluripotent stem cells (iPSCs) during pharmacological drug screening. It is of paramount importance to construct OOCs equipped with highly compact in situ sensors that can accurately monitor, in real time, the extracellular...

Schlieren visualization of focused ultrasound beam steering for spatially specific stimulation of the vagus nerve

In the bioelectronic medicine field, vagus nerve stimulation (VNS) is a promising technique that is expected to treat numerous inflammatory conditions, in addition to the currently FDA approved treatment for epilepsy, depression and obesity [1]. However, current VNS techniques are still limited in the spatial resolution that they can achieve,...

PDMS to Parylene Adhesion Improvement for Encapsulating an Implantable Device

Parylene-C has been used as a substrate and encapsulation material for many implantable medical devices. However, to ensure the flexibility required in some applications, minimize tissue reaction, and protect parylene from degradation in vivo an additional outmost layer of polydimethylsiloxane (PDMS) is desired. In such a scenario, the adhesion...

PDMS-Parylene Adhesion Improvement via Ceramic Interlayers to Strengthen the Encapsulation of Active Neural Implants

Parylene-C has been used as a substrate and encapsulation material for many implantable medical devices. However, to ensure the flexibility required in some applications, minimize tissue reaction, and protect parylene from degradation in vivo an additional outmost layer of polydimethylsiloxane (PDMS) is desired. In such a scenario, the...

Effect of Signals on the Encapsulation Performance of Parylene Coated Platinum Tracks for Active Medical Implants

Platinum is widely used as the electrode material for implantable devices. Owing to its high biostability and corrosion resistivity, platinum could also be used as the main metallization for tracks in active implants. Towards this goal, in this work we investigate the stability of parylene-coated Pt tracks using passive and active tests. The...

Towards a semi-flexible parylene-based platform technology for active implantable medical devices

Active implantable medical devices have been developed for diagnosis, monitoring and treatment of large variety of neural disorders. Since the mechanical properties of these devices need to be matched to the tissue, soft materials, such as polymers are often preferred as a substrate [1]. Parylene is a good candidate, as it is highly...

Pressure measurement of geometrically curved ultrasound transducer array for spatially specific stimulation of the vagus nerve

Vagus nerve stimulators currently on the market can treat epilepsy and depression. Recent clinical trials show the potential for vagus nerve stimulation (VNS) to treat epilepsy, autoimmune disease, and traumatic brain injury. As we explore the benefits of VNS, it is expected that more possibilities for a new treatment will emerge in the future....