Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with high repeatability (1,800 times). Device performance is largely unaffected by bending to radii below 700 µm, which allows for conformal application to the surface of living tissue. The sensing temperature can be tuned between 25 °C and 50 °C, which covers all relevant physiological temperatures. Furthermore, we demonstrate flexible active-matrix thermal sensors which can resolve spatial temperature gradients over a large area. With this flexible ultrasensitive temperature sensor we succeeded in the in vivo measurement of cyclic temperatures changes of 0.1 °C in a rat lung during breathing, without interference from constant tissue motion. This result conclusively shows that the lung of a warm-blooded animal maintains surprising temperature stability despite the large difference between core temperature and inhaled air temperature.

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Measurement of the Optical Properties of Muscle Tissue In Vivo

10.1115/imece2000-2214 ◽

2000 ◽

Author(s):

P. L. Kopsombut ◽

D. Willis ◽

A. E. Schen ◽

L. X. Xu ◽

X. Xu

Keyword(s):

Optical Properties ◽

Transport Theory ◽

Rapid Development ◽

Ccd Camera ◽

High Sensitivity ◽

Biological Tissues ◽

In Vivo Measurement ◽

Living Tissues

Abstract Along with rapid development of diagnostic and therapeutic applications of lasers in medicine, optical properties of various biological tissues have been extensively studied [1]. Most of the studies were performed in vitro owing to the complexity involved in in vivo measurement. To date, it is well understood that living tissue is an absorbing and scattering heterogeneous medium because of its complex structures including blood network. The transport theory cannot be readily used due to the heterogeneity and the absence of the optical properties of living tissues [2]. In this research, we have developed a procedure for measuring the total attenuation coefficient (μ1) of the exteriorized rat 2-D spinotrapezius muscle in the wavelength ranged from 480–560 nm using the collimated light from a Nitrogen-pumped dye laser and a high-sensitivity CCD camera.

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Advances in the fabrication of graphene transistors on flexible substrates

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.8.50 ◽

2017 ◽

Vol 8 ◽

pp. 467-474 ◽

Cited By ~ 16

Author(s):

Gabriele Fisichella ◽

Stella Lo Verso ◽

Silvestra Di Marco ◽

Vincenzo Vinciguerra ◽

Emanuela Schilirò ◽

...

Keyword(s):

Field Effect ◽

Field Effect Transistors ◽

High Mobility ◽

High Sensitivity ◽

Atomic Layer ◽

Transparent Electrode ◽

Large Area ◽

Sensing Applications ◽

Dielectric Performance

Graphene is an ideal candidate for next generation applications as a transparent electrode for electronics on plastic due to its flexibility and the conservation of electrical properties upon deformation. More importantly, its field-effect tunable carrier density, high mobility and saturation velocity make it an appealing choice as a channel material for field-effect transistors (FETs) for several potential applications. As an example, properly designed and scaled graphene FETs (Gr-FETs) can be used for flexible high frequency (RF) electronics or for high sensitivity chemical sensors. Miniaturized and flexible Gr-FET sensors would be highly advantageous for current sensors technology for in vivo and in situ applications. In this paper, we report a wafer-scale processing strategy to fabricate arrays of back-gated Gr-FETs on poly(ethylene naphthalate) (PEN) substrates. These devices present a large-area graphene channel fully exposed to the external environment, in order to be suitable for sensing applications, and the channel conductivity is efficiently modulated by a buried gate contact under a thin Al2O3 insulating film. In order to be compatible with the use of the PEN substrate, optimized deposition conditions of the Al2O3 film by plasma-enhanced atomic layer deposition (PE-ALD) at a low temperature (100 °C) have been developed without any relevant degradation of the final dielectric performance.

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Dynamic blood flow phantom for in vivo liquid biopsy standardization

Scientific Reports ◽

10.1038/s41598-020-80487-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anastasiia Kozlova ◽

Daniil Bratashov ◽

Oleg Grishin ◽

Arkadii Abdurashitov ◽

Ekaterina Prikhozhdenko ◽

...

Keyword(s):

Flow Cytometry ◽

Blood Cells ◽

Liquid Biopsy ◽

High Speed ◽

White Blood Cells ◽

High Sensitivity ◽

Acoustic Properties ◽

Detection Methods ◽

In Vivo Flow Cytometry

AbstractIn vivo liquid biopsy, especially using the photoacoustic (PA) method, demonstrated high clinical potential for early diagnosis of deadly diseases such as cancer, infections, and cardiovascular disorders through the detection of rare circulating tumor cells (CTCs), bacteria, and clots in the blood background. However, little progress has been made in terms of standardization of these techniques, which is crucial to validate their high sensitivity, accuracy, and reproducibility. In the present study, we addressed this important demand by introducing a dynamic blood vessel phantom with flowing mimic normal and abnormal cells. The light transparent silica microspheres were used as white blood cells and platelets phantoms, while hollow polymeric capsules, filled with hemoglobin and melanin, reproduced red blood cells and melanoma CTCs, respectively. These phantoms were successfully used for calibration of the PA flow cytometry platform with high-speed signal processing. The results suggest that these dynamic cell flow phantoms with appropriate biochemical, optical, thermal, and acoustic properties can be promising for the establishment of standardization tool for calibration of PA, fluorescent, Raman, and other detection methods of in vivo flow cytometry and liquid biopsy.

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MiniFAST: A sensitive and fast miniaturized microscope for in vivo neural recording

10.1101/2020.11.03.367466 ◽

2020 ◽

Author(s):

Jill Juneau ◽

Guillaume Duret ◽

Joshua P. Chu ◽

Alexander V. Rodriguez ◽

Savva Morozov ◽

...

Keyword(s):

Open Source ◽

High Speed ◽

High Sensitivity ◽

High Gain ◽

Image Sensor ◽

High Speed Imaging ◽

Light Power ◽

Excitation Light

AbstractObserving the activity of large populations of neurons in vivo is critical for understanding brain function and dysfunction. The use of fluorescent genetically-encoded calcium indicators (GECIs) in conjunction with miniaturized microscopes is an exciting emerging toolset for recording neural activity in unrestrained animals. Despite their potential, current miniaturized microscope designs are limited by using image sensors with low frame rates, sensitivity, and resolution. Beyond GECIs, there are many neuroscience applications which would benefit from the use of other emerging neural indicators, such as fluorescent genetically-encoded voltage indicators (GEVIs) that have faster temporal resolution to match neuron spiking, yet, require imaging at high speeds to properly sample the activity-dependent signals. We integrated an advanced CMOS image sensor into a popular open-source miniaturized microscope platform. MiniFAST is a fast and sensitive miniaturized microscope capable of 1080p video, 1.5 µm resolution, frame rates up to 500 Hz and high gain ability (up to 70 dB) to image in extremely low light conditions. We report results of high speed 500 Hz in vitro imaging of a GEVI and ∼300 Hz in vivo imaging of transgenic Thy1-GCaMP6f mice. Finally, we show the potential for a reduction in photobleaching by using high gain imaging with ultra-low excitation light power (0.05 mW) at 60 Hz frame rates while still resolving Ca2+ spiking activity. Our results extend miniaturized microscope capabilities in high-speed imaging, high sensitivity and increased resolution opening the door for the open-source community to use fast and dim neural indicators.

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High-Speed Holography for In-Vivo Measurement of Acoustically Induced Motions of Mammalian Tympanic Membrane

Mechanics of Biological Systems and Materials, Volume 6 - Conference Proceedings of the Society for Experimental Mechanics Series ◽

10.1007/978-3-319-41351-8_11 ◽

2016 ◽

pp. 75-81 ◽

Cited By ~ 1

Author(s):

Payam Razavi ◽

Jeffrey Tao Cheng ◽

Cosme Furlong ◽

John J. Rosowski

Keyword(s):

Tympanic Membrane ◽

High Speed ◽

In Vivo Measurement

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Characteristics of Sub-micron Polysilicon Thin Film Transistors

MRS Proceedings ◽

10.1557/proc-345-129 ◽

1994 ◽

Vol 345 ◽

Cited By ~ 1

Author(s):

Kola R Olasupo ◽

Professor M. K. Hatalis

Keyword(s):

Thin Film ◽

Leakage Current ◽

High Speed ◽

Thin Film Transistor ◽

Random Access ◽

Channel Length ◽

Large Area ◽

Short Channel ◽

Active Matrix ◽

Static Random Access Memories

AbstractThe polysilicon thin film transistor has been actively studied for the large area display applications like active matrix liquid crystal displays and for load cell in static random access memories. Due to low effective carrier mobility in polysilicon, the circuit speed is limited. Since the circuit delay time is directly proportional to the square of the channel length, short channel TFTs will be advantageous for high speed applications. In this work, we have studied the current voltage characteristics of an inverted sub-micron P-channel polysilicon thin-film transistor with self-aligned LDD structure to obtain a well-controlled channel and drain offset lengths. The particular features we examined are the leakage current and mobility. The leakage current and the ON current were found to be in the picoamp and micro-amp range respectively for devices having channel length in the range of 1.0μm to 0.35μm. Even very small devices having L&W = 0.35μm × 0.35μm exhibited characteristics similar to wider devices. The on/off current ratio was in the order of 105 before hydrogenation.

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Biometric Measurement of Anterior Segment: A Review

Sensors ◽

10.3390/s20154285 ◽

2020 ◽

Vol 20 (15) ◽

pp. 4285

Author(s):

Bin Liu ◽

Chengwei Kang ◽

Fengzhou Fang

Keyword(s):

High Speed ◽

Anterior Segment ◽

Future Research ◽

Basic Principles ◽

Human Eye ◽

In Vivo Measurement ◽

Research Perspectives ◽

Scattering Effects ◽

Fine Resolution

Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.

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Direct Measurement and Modeling of Intraglottal, Subglottal, and Vocal Fold Collision Pressures during Phonation in an Individual with a Hemilaryngectomy

Applied Sciences ◽

10.3390/app11167256 ◽

2021 ◽

Vol 11 (16) ◽

pp. 7256

Author(s):

Daryush D. Mehta ◽

James B. Kobler ◽

Steven M. Zeitels ◽

Matías Zañartu ◽

Emiro J. Ibarra ◽

...

Keyword(s):

Vocal Fold ◽

High Speed ◽

Pressure Sensors ◽

Pressure Probe ◽

Surgical Removal ◽

In Vivo Measurement ◽

Dual Sensor ◽

The Right ◽

Collision Pressure

The purpose of this paper is to report on the first in vivo application of a recently developed transoral, dual-sensor pressure probe that directly measures intraglottal, subglottal, and vocal fold collision pressures during phonation. Synchronous measurement of intraglottal and subglottal pressures was accomplished using two miniature pressure sensors mounted on the end of the probe and inserted transorally in a 78-year-old male who had previously undergone surgical removal of his right vocal fold for treatment of laryngeal cancer. The endoscopist used one hand to position the custom probe against the surgically medialized scar band that replaced the right vocal fold and used the other hand to position a transoral endoscope to record laryngeal high-speed videoendoscopy of the vibrating left vocal fold contacting the pressure probe. Visualization of the larynx during sustained phonation allowed the endoscopist to place the dual-sensor pressure probe such that the proximal sensor was positioned intraglottally and the distal sensor subglottally. The proximal pressure sensor was verified to be in the strike zone of vocal fold collision during phonation when the intraglottal pressure signal exhibited three characteristics: an impulsive peak at the start of the closed phase, a rounded peak during the open phase, and a minimum value around zero immediately preceding the impulsive peak of the subsequent phonatory cycle. Numerical voice production modeling was applied to validate model-based predictions of vocal fold collision pressure using kinematic vocal fold measures. The results successfully demonstrated feasibility of in vivo measurement of vocal fold collision pressure in an individual with a hemilaryngectomy, motivating ongoing data collection that is designed to aid in the development of vocal dose measures that incorporate vocal fold impact collision and stresses.

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