A Micro-Thermal Sensor for Focal Therapy Applications

Natesan, Harishankar; Hodges, Wyatt; Choi, Jeunghwan; Lubner, Sean; Dames, Chris; Bischof, John C.

doi:10.1038/srep21395

Cited by 13 publications

(8 citation statements)

References 41 publications

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“…[1][2][3] Recent efforts involve application to biological samples (100 µm to 3 mm thick slices of liver and cardiac tissue obtained using ex vivo preparations) using 3ω sensors constructed on rigid planar substrates. [4][5][6] The implementation of sensors constructed in soft, flexible and stretchable forms could create opportunities for direct, in vivo measurements on the soft, curved tissues of living organisms. [7][8][9][10][11][12][13][14] Devices constructed using the principles of stretchable electronics can measure thermal transport properties of human skin.…”

Section: Introductionmentioning

confidence: 99%

Flexible and Stretchable 3ω Sensors for Thermal Characterization of Human Skin

Tian

Webb

et al. 2017

Adv Funct Materials

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Characterization of the thermal properties of the surface and sub-surface structures of the skin can reveal the degree of hydration, the rate of blood flow in near-surface micro and macrovasculature, and other important physiological information of relevance to dermatological and overall health status. Here, we introduce a soft, stretchable thermal sensor, based on the so-called three omega (i.e. 3ω) method, for accurate characterization of the thermal conductivity and diffusivity of materials systems, such as the skin, that can be This article is protected by copyright. All rights reserved. 5 challenging to measure using established techniques. Experiments on skin at different body locations and under different physical states demonstrate the possibilities. Systematic studies establish the underlying principles of operation in these unusual systems, thereby allowing rational design and use of these types of devices, through combined investigations based on analytical modeling, experimental measurements and finite element analysis. The findings create broad opportunities for the use of 3ω methods in biology, with utility ranging from the integration with surgical tools or implantable devices to non-invasive uses in clinical diagnostics and therapeutics.

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Section: Introductionmentioning

confidence: 99%

Flexible and Stretchable 3ω Sensors for Thermal Characterization of Human Skin

Tian

Webb

et al. 2017

Adv Funct Materials

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“…In such cases, however, boundary conditions become significant, and the substrate ( t substrate ) and sample thicknesses ( t sample ) must satisfy a semi-infinite condition: t substrate / h > 5, t sample / h > 5 for < 1% error in measured k of the sample. 144 …”

Section: Techniques For Meauring the Isotropic Effective Thermal Tran...mentioning

confidence: 99%

Advanced thermal sensing techniques for characterizing the physical properties of skin

Madhvapathy

Arafa

Patel

et al. 2022

Applied Physics Reviews

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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.

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“…One other interesting feature of the 3 ω sensing approach is the ability to utilize the frequency dependence of thermal waves propagation which provides new opportunities, e.g., detection of nearby phase boundaries [ 18 ]. Notwithstanding the limited sensitivity of resistive sensors and other limitations of the supported 3 ω electrothermal techniques, such measurement approach may be realized in the form of thermal sensors integrated with traditional medical instruments [ 19 ]. Other recent developments have provided a variety of miniaturized titration calorimeters [ 20 ] and other microfluidic based instruments, and together with ingenious experimental approaches suitable for the analysis of fast reactions [ 21 ] proteins in solution [ 22 ] or isolated single cells [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

AC/DC Thermal Nano-Analyzer Compatible with Bulk Liquid Measurements

et al. 2022

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Nanocalorimetry, or thermal nano-analysis, is a powerful tool for fast thermal processing and thermodynamic analysis of materials at the nanoscale. Despite multiple reports of successful applications in the material sciences to study phase transitions in metals and polymers, thermodynamic analysis of biological systems in their natural microenvironment has not been achieved yet. Simply scaling down traditional calorimetric techniques, although beneficial for material sciences, is not always appropriate for biological objects, which cannot be removed out of their native biological environment or be miniaturized to suit instrument limitations. Thermal analysis at micro- or nano-scale immersed in bulk liquid media has not yet been possible. Here, we report an AC/DC modulated thermal nano-analyzer capable of detecting nanogram quantities of material in bulk liquids. The detection principle used in our custom-build instrument utilizes localized heat waves, which under certain conditions confine the measurement area to the surface layer of the sample in the close vicinity of the sensing element. To illustrate the sensitivity and quantitative capabilities of the instrument we used model materials with detectable phase transitions. Here, we report ca. 106 improvement in the thermal analysis sensitivity over a traditional DSC instrument. Interestingly, fundamental thermal properties of the material can be determined independently from heat flow in DC (direct current) mode, by using the AC (alternating current) component of the modulated heat in AC/DC mode. The thermal high-frequency AC modulation mode might be especially useful for investigating thermal transitions on the surface of material, because of the ability to control the depth of penetration of AC-modulated heat and hence the depth of thermal sensing. The high-frequency AC mode might potentially expand the range of applications to the surface analysis of bulk materials or liquid-solid interfaces.

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A Micro-Thermal Sensor for Focal Therapy Applications

Cited by 13 publications

References 41 publications

Flexible and Stretchable 3ω Sensors for Thermal Characterization of Human Skin

Flexible and Stretchable 3ω Sensors for Thermal Characterization of Human Skin

Advanced thermal sensing techniques for characterizing the physical properties of skin

AC/DC Thermal Nano-Analyzer Compatible with Bulk Liquid Measurements

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