Once ultrasonic wave strikes the μLight, the piezoelectric receiver starts generating electrical power and turns on the on-board LEDs.
The light from LEDs will activate the pre-delivered PS and initiate the PDT.
Easy insertion via a biopsy needle.
Piezoelectric receiver feeds AC signal to a full-wave rectifying circuit to create a constant DC voltage for electrolysis.
The electrolytically-generated gas pressure will be accumulated for pumping the drug out.
Flow rate of 0.1 μL/s with a backpressure of 24.2 Torr.
Blast-induced traumatic brain injury (bTBI) has been linked to a multitude of delayed-onset neurodegenerative and neuropsychiatric disorders, but complete understanding of their pathogenesis remains elusive. To develop mechanistic relationships between bTBI and post-blast neurological sequelae, it is imperative to characterize the initiating traumatic mechanical events leading to eventual alterations of cell, tissue, and organ structure and function. This paper presents a wireless sensing system capable of monitoring the intracranial brain deformation in real-time during the event of a bTBI. The system consists of an implantable soft magnet and an external head-mounted magnetic sensor that is able to measure the field in three dimensions. The change in the relative position of the soft magnet WITH respect to the external sensor as the result of the blast wave induces changes in the magnetic field. The magnetic field data in turn is used to extract the temporal and spatial motion of the brain under the blast wave in real-time. The system has temporal and spatial resolutions of 5 μs and 10 μm. Following the characterization and validation of the sensor system, we measured brain deformations in a live rodent during a bTBI.Publications
We report on a novel electromechanical energy scavenging and wireless interrogation scheme using low frequency components of musical vibrations. The device incorporates a piezoelectric cantilever beam that converts the acoustic vibrations into electric power; rectifying circuitry; a storage capacitor in parallel with a PDMS based inductive pressure sensor; and a ferrite core. Musical sound wave from a loudspeaker induces vibrations in the piezoelectric cantilever at harmonics, which match its resonant frequency. This, in turn generates a voltage that is rectified and stored in the capacitor. At non-resonant harmonics, the supply is interrupted, causing the stored charge to be dumped into the sensing LC tank inducing oscillations at its natural frequency, which is picked up externally with a receiver coil. Applying pressure reduces the distance between the ferrite core and the coil, changing the inductance and hence modulating the resonance frequency of the LC tank.Multimedia Publications
In this paper we present an ultrasonically-powered implantable micro oxygen generator (IMOG) that is capable of in situ tumor oxygenation through water electrolysis. Such active mode of oxygen generation is not affected by increased interstitial pressure or abnormal blood vessels that typically limit the systemic delivery of oxygen to hypoxic regions of solid tumors. Wireless ultrasonic powering (2.15 MHz) was employed to increase the penetration depth and eliminate the directional sensitivity associated with magnetic methods. In addition, ultrasonic powering allowed for further reduction in the total size of the implant by eliminating the need for a large area inductor. IMOG has an overall dimension of 1.2x1.3x8 mm^3, small enough to be implanted using a hypodermic needle or a trocar. In vitro and ex vivo experiments showed the IMOG is capable of generating more than 150 mA which in turn can create 0.525 ml/min of oxygen through electrolytic dissociation. In vivo experiments in a well-known hypoxic pancreatic tumor model (1 cm^3 in size) also verified adequate in situ tumor oxygenation in less than 10 minutes.