Wireless sensing for the study of traumatic brain injury

Traumatic brain injury - blast - magnetic sensor

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

Smart Gait

Smartphone - gait analysis - fall monitoring - health - protection

Our goal was to develop an inexpensive and accurate gait tracking device that could be easily implemented in the field by researchers and clinicians. Measures of step length (SL) and step width (SW) variability are critical because they are linked to falls. However, these measures cannot be captured with current devices for field research. The simplest and most widely available approach was to use the Smartphone camera (attached at the waist) to capture SL and SW. Using a camera may appear impractical due to the following challenges: calibration of a moving camera, obstruction of the field of view, trunk motion, etc. We have addressed these challenges in the development of a new device, the SmartGait.

Project website Multimedia Publications

Low cost radiation dosimeter utilizing organic materials

Radiation, dosimeter, and microorganism (yeast)

Living matter undergoes physical (sometimes lethal) damage to their DNA when exposed to the ionizing radiation. If such physiochemical alterations to the DNA can be utilized to measure the absorbed dosage, it can provide an invaluable information regarding the biological damage to the organism. One particular organism that can serve such purpose (radiation surrogate) is the yeast, a eukaryotic microorganism with wide and ancient commercial applications in food and beverage industry. Yeast is a well-studied microorganism having homologous genetic sequence to humans. Based on this noble idea, the low-cost, wearable, film-type radiation sensor is developed that utilizes yeast as the sensing material, hence, producing an output that can be directly correlated to the DNA damage and cellular inactivation/death. Our impedance-based sensor output is a function of fermentation byproducts (i.e., generated CO2 and resulting dissolved carbonic acid) of the surviving yeast (S. cerevisiae) after exposure to the ionizing radiation. A prototype sensor with dimensions of 18×18mm2 shows a maximum sensitivity of 0.154 Ω/Ω0decade-rad.

Publications

Smart Capsule

GI-Tract-Location-Specific Payload Release - Magnetic Actuation

Once activated through a magnetic proximity fuse, the capsule opens up and releases its powdered payload in a location specified by an implanted miniature magnetic marker or an externally-worn larger magnet. The capsule (9 mm × 26 mm) comprises of two compartments; one contains a charged capacitor and a reed switch while the second one houses the drug reservoir capped by a taut nylon thread intertwined with a nichrome wire. The nichrome wire is connected to the capacitor through the reed switch. The capacitor is charged to 2.7V before ingestion and once within the proximity of the permanent magnet; the reed switch closes, discharging the capacitor through the nichrome wire, melting the nylon thread, detaching the cap and emptying the drug reservoir.

Multimedia Publications

Laser-micromachining enables Scotch tape a low-cost smart material

self-forming swimmer - gripper - nanoparticles functionalizing - moisture responsive

An off-the-shelf, moisture-responsive, acetate-backed adhesive tape is investigated as a commercially available smart material for fabricating low-cost, multifunctional, humidity-responsive millimeter-scale structures. Laser ablation is used for cutting and thinning-down the tape to enhance its response. Water-submerged cantilevers show a radius of curvature of 3 mm or lower (for laser-thinned cantilevers). Additionally, their humidity response is a function of the angle between the longitudinal axis of the cantilever and polymer orientation. The tapes could be further functionalized with magnetic particles and used to create four-finger grippers and self-forming swimmer.

Multimedia Publications

Nanoparticle-enabled Wireless Monitoring

Characterization of degradation kinetics in pharmaceutical gelatin films

Degradation kinetics of pharmaceutical excipient films effect their overall performance and drug release profile. Characterizing them is traditionally labor-intensive and time-consuming, requiring spectroscopy or periodic mass measurements. Here we present an alternative rapid technique for electrically (and wirelessly) measuring the polymeric matrix swelling and material degradation in aqueous media for characterizing functional films. The film is loaded with ferromagnetic nanoparticles and used as the core of a planar coil whose resonant frequency is monitored remotely. When placed in an aqueous solution, swelling and dissolution of the film induce contrasting changes in the capacitance and inductance of the coil, respectively, allowing identification of the swelling and dissolution phases. The dissolution profile of iron oxide-loaded gelatin is compared with spectrophotometry data, further demonstrating the technique can distinguish among films with various levels of crosslinking (showing a resonant frequency difference of 116 kHz between completely non-crosslinked and fully crosslinked gelatin). The key characteristics of the film degradation kinetics can be captured within 20�?0 minutes of data collection.

Publication