Private medical device company Rhaeos, which is focused on the care of patients with chronic medical conditions, announced the issuance of U.S. patents  that cover flexible, wearable sensors for non-invasive monitoring of subdermal fluid flow.
These patents include wearable sensors that address cerebrospinal fluid in hydrocephalus shunts and blood flow in both capillaries and large vessels.
Biological fluid flow is a key diagnostic and therapeutic biomarker for numerous chronic medical conditions including hydrocephalus, where cerebrospinal fluid flow in implanted ventriculoperitoneal shunts is of critical importance. However, quantified analysis of biological fluid flow is often frustrated by the need for invasive fluid access, the use of bulky wired electronics that tether the patient, and motion artifacts in skin-mounted probes.
Rhaeos’ novel Epidermal Thermal Flow Sensor technology is designed to overcome these limitations by enabling a small, wireless, flexible device that gently adheres to the skin like a soft bandage. Novel mechanical and thermal engineering approaches result in a sensor that can measure flow-induced temperature responses on skin with a precision of one hundredth of a degree. These improvements, combined with advanced analytics, enable reliable flow measurements with incredible precision down to a few microliters per minute.
“The challenge in biological flow sensing is getting useful signals without physically contacting the fluid and without immobilizing the patient,” says R. Chad Webb, PhD, chief technical officer. “This technology overcomes both challenges by mechanically matching the sensor to the skin surface, eliminating motion-induced measurement noise and enabling reliable detection of the subtle flow-induced thermal responses”.
The technology has been demonstrated in multiple pilot studies showing effectiveness across a range of healthcare applications, with peer-reviewed publications in Nature and Science family journals, among others. The technology is also a key enabler of FlowSense, a Rhaeos product currently being used in a pivotal clinical trial for monitoring cerebrospinal fluid flow in hydrocephalus shunts.
“The ability to noninvasively measure flow through biological systems is broadly useful for a number of medical applications,” says Siddharth R. Krishnan, PhD, Rhaeos Co-Founder. “We’re very excited about the potential to improve care for patients with hydrocephalus, where the measurement of cerebrospinal fluid flow through implanted shunt systems could allow us to identify aberrant patterns and malfunctions more efficiently.”
U.S. Patent No. 11,160,458, “Epidermal Devices for Analysis of Temperature and Thermal Transport Characteristics”, describes sensor designs and analytical methods for thermal analysis of tissue, including noninvasively monitoring fluids such as blood flow. Meanwhile, U.S. Patent No. 11,259,754, “Wireless and Noninvasive Epidermal Electronics,” describes conformable devices to measure subdermal fluid flow and related methods.
These novel devices and methods enable the detection of thermal flow signals by employing key materials, geometries, and signal processing techniques.
Rhaeos, Inc. has exclusive worldwide rights to commercialize these inventions as part of a broad intellectual property portfolio generated internally and licensed from Northwestern University and the University of Illinois.