Advanced thermal sensing techniques for characterizing the physical properties of skin

Abstract

Measurements of the thermal properties of the skin can serve as the basis for a noninvasive, quantitative characterization of dermatological health and physiological status. Applications range from the detection of subtle spatiotemporal changes in skin temperature associated with thermoregulatory processes, to the evaluation of depth-dependent compositional properties and hydration levels, to the assessment of various features of microvascular/macrovascular blood flow. Examples of recent advances for performing such measurements include thin, skin-interfaced systems that enable continuous, real-time monitoring of the intrinsic thermal properties of the skin beyond its superficial layers, with a path to reliable, inexpensive instruments that offer potential for widespread use as diagnostic tools in clinical settings or in the home. This paper reviews the foundational aspects of the latest thermal sensing techniques with applicability to the skin, summarizes the various devices that exploit these concepts, and provides an overview of specific areas of application in the context of skin health. A concluding section presents an outlook on the challenges and prospects for research in this field.

Battery-Free Optoelectronic Patch for Photodynamic and Light Therapies in Treating Bacteria-Infected Wounds

“…In conjunction with comfort evaluations, a series of light therapy sessions are conducted with an optoelectronic patch on the infected wound mice. Pseudomonas aeruginosa ( P. aeruginosa ), a Gram-negative bacillus, is well-known for causing opportunistic infections in immunocompromised individuals( 37 ). The pathogen is associated with a wide range of clinical conditions, ranging from localized skin problems to serious systemic illnesses.…”

Low-dimensional nanostructures for monolithic 3D-integrated flexible and stretchable electronics

“…Temperature sensors commonly used include resistance pyroelectric temperature detectors (PTDs), temperature detectors (RTDs), and thermistors. [203][204][205] PTDs consist of a ceramic oxide or piezoelectric crystals, with electrodes formed on both surfaces of the element. When there is a change in temperature within the sensor's monitoring range, the pyroelectric effect generates an electric charge on the two electrodes, resulting in the production of a weak voltage between the two electrodes.…”

Variations of skin thermal diffusivity on different skin regions

“…Numerous devices have been proposed in the literature to measure the thermal properties of the skin in vivo 10–26 . More recently, wearables have emerged as a solution for continuous monitoring 27–37 . However, to date, only a few studies have been devoted to investigating the potential correlation between thermal parameters and relevant physiological value.…”