Sree Koneru is pursuing his PhD in Biomedical Engineering from the department of Bioengineering at Binghamton University. His Bioengineering undergraduate degree from Binghamton gave him a valuable complex systems perspective and showed how inspiration from biology can work wonders in engineering.
Sree is a research associate with the Clinical Science and Engineering Research Center at Binghamton, and the group develops non-invasive technologies geared toward early diagnosis, intervention, and treatment of chronic medical conditions. His current research is focused on understanding how electromagnetic fields affect tissue, and is developing a wireless TENS device that can provide drug-free and safe chronic pain relief.
Sree believes that the reductionist approach will not work for next-gen engineering, and that an understanding of complex systems will be key to innovating the future. He is hooked on the outdoors and loves to play almost any sport.
Project: AC Wave Propagation & Reflection through Tissue
The use of electrical fields to treat chronic pain is quite common and has been used for over 50 years now. Transcutaneous Electrical Nerve Stimulation (TENS) is a very popular device that utilizes electrodes on the skin surface to produce DC electric fields in the tissue sufficiently high to stimulate large (Ia type) nerve fibers. To electrically stimulate a single Type Ia nerve fiber is known to require an induced electric field in the tissue of 30-100V/m for durations inversely proportional to the field intensity. These high field intensities preclude prolonged TENS usage as such fields can produce skin damage. A wireless approach to TENS could overcome this challenge due to ease with which radio frequency fields cross the skin, and such a device would allow for usage over damaged skin/wounds and bandaging.
While the prospect of a wireless TENS device is exciting, nerves are not sensitive to radio-frequency (RF) fields. The bio-electromagnetics literature has clearly demonstrated that beyond 10 MHz, RF fields do not significantly influence nerve, muscle, or other tissues in the body, except through thermal effects, because no rectification process above 10 MHz has been shown to exist. As these observations were made using a reductionist perspective, we’ve demonstrated that rectification of HF RF fields can be created when a load-dependent RF generator is driving the system, and the system is well cross-coupled. This 1D modeling work done in Mathematica, along with results from an early prototype, suggest that under certain conditions one might be able to observe a DC component and subsequent nerve stimulation using sub-threshold RF fields.
In the NKS school, we have decided to investigate if this phenomenon can be simulated in a two-dimensional tissue model. Understanding if and how this phenomenon emerges at certain tissue depths will bring us closer to developing a fully functional wireless TENS device.
Favorite Four-Color, Four State Turing Machine