Wireless, battery-free, flexible, miniaturized dosimeters monitor exposure to solar radiation and to light for phototherapy

Abstract

Exposure to electromagnetic radiation can have a profound impact on human health. Ultraviolet (UV) radiation from the sun causes skin cancer. Blue light affects the body’s circadian melatonin rhythm. At the same time, electromagnetic radiation in controlled quantities has beneficial use. UV light treats various inflammatory skin conditions, and blue light phototherapy is the standard of care for neonatal jaundice. Although quantitative measurements of exposure in these contexts are important, current systems have limited applicability outside of laboratories because of an unfavorable set of factors in bulk, weight, cost, and accuracy. We present optical metrology approaches, optoelectronic designs, and wireless modes of operation that serve as the basis for miniature, low-cost, and battery-free devices for precise dosimetry at multiple wavelengths. These platforms use a system on a chip with near-field communication functionality, a radio frequency antenna, photodiodes, supercapacitors, and a transistor to exploit a continuous accumulation mechanism for measurement. Experimental and computational studies of the individual components, the collective systems, and the performance parameters highlight the operating principles and design considerations. Evaluations on human participants monitored solar UV exposure during outdoor activities, captured instantaneous and cumulative exposure during blue light phototherapy in neonatal intensive care units, and tracked light illumination for seasonal affective disorder phototherapy. Versatile applications of this dosimetry platform provide means for consumers and medical providers to modulate light exposure across the electromagnetic spectrum in a way that can both reduce risks in the context of excessive exposure and optimize benefits in the context of phototherapy.

Wireless battery-free body sensor networks using near-field-enabled clothing

“…Current solutions for wireless sensor interconnection either require each sensor to be independently powered (such as with batteries) 11,[17][18][19][20][21][22][23] or have a very limited range of operation (few centimetres) [32][33][34][35][36][37][38][39] . Networks of skin-mountable sensors use.…”

“…Near-field communication (NFC) is an alternative wireless technology in which sensors are inductively powered by a wireless reader 25,31 . Because NFC-based sensors can be battery-free, low-cost, and secure against eavesdropping, this technology has emerged as a versatile platform for developing skin-mounted or implanted electronics capable of measuring heart rate, tissue oxygenation, sweat electrolyte composition, ultraviolet light exposure, and other physiological parameters [32][33][34][35][36][37][38][39] . A major limitation of NFC technology, however, is that the sensors can function only within the near-field of the reader, which is at most a few centimetres for a mobile reader such as a smartphone 25,31 .…”

Flexible Hybrid Electronics for Digital Healthcare

“…i) A millimeter‐scale, wireless, and battery‐free platform on a finger to monitor exposure to solar radiation and to light for phototherapy. Reproduced with permission . Copyright 2018, American Association for the Advancement of Science.…”

Printing Flexible and Hybrid Electronics for Human Skin and Eye‐Interfaced Health Monitoring Systems

“…Wearable monitoring devices provide capabilities for scheduled and continuous evaluation of vital signs and activity (e.g., temperature, blood pressure, perspiration rate, muscle fatigue, and electrophysiological signals) and clinically important biomarkers (e.g., electrolytes, metabolites, and enzymes), which are particularly beneficial to in‐home care, rehabilitation, and pain management services to patients with known and suspected health risks . The most compelling versions of wearable monitoring often demand direct integration of flexible and even stretchable devices with the human body, allowing for accurate detection and quantitation of the body signals . The basic requirements for such devices include: i) medical‐grade biocompatibility for safety in clinical use, ii) minimal irritation on the body for comfort, iii) easy and unobtrusive fit to a specific area of the body for enhanced usability and improved signal quality (e.g., signal‐to‐noise ratio), and iv) mechanical longevity and durability throughout the entire lifetime that may involve thousands of cycles of elastic deformations by the body movements.…”