scholarly journals THz Sensing of Human Skin: A Review of Skin Modeling Approaches

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3624
Author(s):  
Jiarui Wang ◽  
Hannah Lindley-Hatcher ◽  
Xuequan Chen ◽  
Emma Pickwell-MacPherson
Keyword(s):  
Biomedical Applications ◽  
Structural Changes ◽  
High Sensitivity ◽  
Thz Radiation ◽  
Thz Imaging ◽  
High Attenuation ◽  
Non Invasive ◽  
Correct Model ◽  
Imaging And Spectroscopy

The non-ionizing and non-invasive nature of THz radiation, combined with its high sensitivity to water, has made THz imaging and spectroscopy highly attractive for in vivo biomedical applications for many years. Among them, the skin is primarily investigated due to the short penetration depth of THz waves caused by the high attenuation by water in biological samples. However, a complete model of skin describing the THz–skin interaction is still needed. This is also fundamental to reveal the optical properties of the skin from the measured THz spectrum. It is crucial that the correct model is used, not just to ensure compatibility between different works, but more importantly to ensure the reliability of the data and conclusions. Therefore, in this review, we summarize the models applied to skin used in the THz regime, and we compare their adaptability, accuracy, and limitations. We show that most of the models attempt to extract the hydration profile inside the skin while there is also the anisotropic model that displays skin structural changes in the stratum corneum.

scholarly journals Monitoring the Effect of Transdermal Drug Delivery Patches on the Skin Using Terahertz Sensing

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2052
Author(s):  
Hannah Lindley-Hatcher ◽  
Jiarui Wang ◽  
Arturo I. Hernandez-Serrano ◽  
Joseph Hardwicke ◽  
Gabit Nurumbetov ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Water Content ◽  
Biomedical Applications ◽  
Skin Barrier ◽  
High Sensitivity ◽  
Thz Spectroscopy ◽  
Transdermal Patches ◽  
Patch Removal ◽  
Terahertz Sensing

Water content of the skin is an important parameter for controlling the penetration rate of chemicals through the skin barrier; therefore, for transdermal patches designed for drug delivery to be successful, the effects of the patches on the water content of the skin must be understood. Terahertz (THz) spectroscopy is a technique which is being increasingly investigated for biomedical applications due to its high sensitivity to water content and non-ionizing nature. In this study, we used THz measurements of the skin (in vivo) to observe the effect of partially and fully occlusive skin patches on the THz response of the skin after the patches had been applied for 24 h. We were able to observe an increase in the water content of the skin following the application of the patches and to identify that the skin remained hyper-hydrated for four hours after the removal of the fully occlusive patches. Herein, we show that THz spectroscopy has potential for increasing the understanding of how transdermal patches affect the skin, how long the skin takes to recover following patch removal, and what implications these factors might have for how transdermal drug patches are designed and used.

scholarly journals Anterior visual system imaging to investigate energy failure in multiple sclerosis

Brain ◽  
2020 ◽  
Vol 143 (7) ◽  
pp. 1999-2008 ◽  
Author(s):  
Iris Kleerekooper ◽  
Axel Petzold ◽  
S Anand Trip
Keyword(s):  
Multiple Sclerosis ◽  
Visual System ◽  
Adaptive Optics ◽  
Mitochondrial Function ◽  
Structural Changes ◽  
Future Research ◽  
Optical Coherence ◽  
Non Invasive ◽  
Invasive Techniques

Abstract Mitochondrial failure and hypoxia are key contributors to multiple sclerosis pathophysiology. Importantly, improving mitochondrial function holds promise as a new therapeutic strategy in multiple sclerosis. Currently, studying mitochondrial changes in multiple sclerosis is hampered by a paucity of non-invasive techniques to investigate mitochondrial function of the CNS in vivo. It is against this backdrop that the anterior visual system provides new avenues for monitoring of mitochondrial changes. The retina and optic nerve are among the metabolically most active structures in the human body and are almost always affected to some degree in multiple sclerosis. Here, we provide an update on emerging technologies that have the potential to indirectly monitor changes of metabolism and mitochondrial function. We report on the promising work with optical coherence tomography, showing structural changes in outer retinal mitochondrial signal bands, and with optical coherence angiography, quantifying retinal perfusion at the microcapillary level. We show that adaptive optics scanning laser ophthalmoscopy can visualize live perfusion through microcapillaries and structural changes at the level of single photoreceptors and neurons. Advantages and limitations of these techniques are summarized with regard to future research into the pathology of the disease and as trial outcome measures.

scholarly journals Non-invasive chemically specific measurement of subsurface temperature in biological tissues using surface-enhanced spatially offset Raman spectroscopy

2016 ◽  
Vol 187 ◽  
pp. 329-339 ◽  
Author(s):  
Benjamin Gardner ◽  
Nicholas Stone ◽  
Pavel Matousek
Keyword(s):  
Raman Spectroscopy ◽  
High Sensitivity ◽  
Biological Tissues ◽  
Temperature Monitoring ◽  
Subsurface Temperature ◽  
Non Invasive ◽  
Wide Range ◽  
Subsurface Monitoring ◽  
Mean Square Errors

Here we demonstrate for the first time the viability of characterising non-invasively the subsurface temperature of SERS nanoparticles embedded within biological tissues using spatially offset Raman spectroscopy (SORS). The proposed analytical method (T-SESORS) is applicable in general to diffusely scattering (turbid) media and features high sensitivity and high chemical selectivity. The method relies on monitoring the Stokes and anti-Stokes bands of SERS nanoparticles in depth using SORS. The approach has been conceptually demonstrated using a SORS variant, transmission Raman spectroscopy (TRS), by measuring subsurface temperatures within a slab of porcine tissue (5 mm thick). Root-mean-square errors (RMSEs) of 0.20 °C were achieved when measuring temperatures over ranges between 25 and 44 °C. This unique capability complements the array of existing, predominantly surface-based, temperature monitoring techniques. It expands on a previously demonstrated SORS temperature monitoring capability by adding extra sensitivity stemming from SERS to low concentration analytes. The technique paves the way for a wide range of applications including subsurface, chemical-specific, non-invasive temperature analysis within turbid translucent media including: the human body, subsurface monitoring of chemical (e.g. catalytic) processes in manufacture quality and process control and research. Additionally, the method opens prospects for control of thermal treatment of cancer in vivo with direct non-invasive feedback on the temperature of mediating plasmonic nanoparticles.

scholarly journals In-vivo monitoring and quantification of breast cancer growth dynamics with non-invasive intravital mesoscopic fluorescence molecular tomography

2020 ◽  
Author(s):  
Mehmet S. Ozturk ◽  
Marta G. Montero ◽  
Ling Wang ◽  
Lucas M. Chaible ◽  
Martin Jechlinger ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Tumor Cells ◽  
Tumor Volume ◽  
Residual Disease ◽  
Growth Dynamics ◽  
Treatment Phase ◽  
High Sensitivity ◽  
Fluorescence Molecular Tomography ◽  
Non Invasive

Preclinical breast tumor models are an invaluable tool to systematically study tumor progression and treatment response, yet methods to non-invasively monitor the involved molecular and mechanistic properties under physiologically relevant conditions are limited. Here we present an intravital mesoscopic fluorescence molecular tomography (henceforth IFT) approach that is capable of tracking fluorescently labeled tumor cells in a quantitative manner inside the mammary gland of living mice. Our mesoscopic approach is entirely non-invasive and thus permits prolonged observational periods of several months. The relatively high sensitivity and spatial resolution further enable inferring the overall number of oncogene-expressing tumor cells as well as their tumor volume over the entire cycle from early tumor growth to residual disease following the treatment phase. We find that sheer tumor volume, as commonly assessed by other imaging modalities, is not well correlated to tumor cell quantity, hence our IFT approach is a promising new method for studying tumor growth dynamics in a quantitative and longitudinal fashion in-vivo.

scholarly journals TMOD-22. AKALUC BIOLUMINESCENCE OFFERS SUPERIOR SENSITIVITY TO TRACK IN VIVO GBM EXPANSION

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii232-ii232
Author(s):  
Dominique Bozec ◽  
Anirudh Sattiraju ◽  
Alexandros Bouras ◽  
Joe Gerald Jesu Raj ◽  
Daniel Rivera ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Current Method ◽  
Firefly Luciferase ◽  
Brain Parenchyma ◽  
Therapeutic Effects ◽  
Non Invasive ◽  
Longitudinal Tracking ◽  
Cancer Studies

Abstract Longitudinal tracking of tumor growth using non-invasive bioluminescence imaging (BLI) is a key approach for in vivo cancer studies, but the current method of firefly luciferase (Fluc) BLI has quantitative limitations, as it is only suited for detection of tumors of considerable sizes at advanced stage, typically in the order of >105 cells. Recently, Akaluciferase (Akaluc) has been developed as an alternative BLI system that offers higher signal strength and better light penetration of tissue due to its red-shifted emission. Here, we established Akaluc BLI as a new sensitive method for in vivo tracking of glioblastoma (GBM) expansion in intracranial transplant models. In multiple GBM cell lines, including the frequently used U87MG and GL261, as well as patient-derived glioma stem cells (GSC), we demonstrate that Akaluc-expressing GBM cells produced more than 50-times brighter BLI signals in vitro and up to 100-fold higher signal intensities in vivo over Fluc-expressing counterparts. The higher sensitivity of Akaluc BLI permits early in vivo detection of intracranial GBM transplants starting as early as 4 hours after implantation and with as little as 5,000 transplanted GSC. We also reveal a prolonged engraftment period in intracranial GSC transplants before wide dissemination into host brain parenchyma. Akaluc BLI is also advantageous for longitudinal monitoring of therapeutic effects of chemoradiation for GBM and detection of early phase of tumor relapse. Thus, Akaluc BLI offers an important addition to the tool box for cancer research. SIGNIFICANCE: The high sensitivity of Akaluc bioluminescence is a significant improvement for the non-invasive tracking of tumors in preclinical cancer studies, including detection of small incipient tumors and micro-metastasis.

scholarly journals Intravital mesoscopic fluorescence molecular tomography allows non-invasive in vivo monitoring and quantification of breast cancer growth dynamics

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mehmet S. Ozturk ◽  
Marta G. Montero ◽  
Ling Wang ◽  
Lucas M. Chaible ◽  
Martin Jechlinger ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Tumor Cells ◽  
Residual Disease ◽  
Growth Dynamics ◽  
Treatment Phase ◽  
High Sensitivity ◽  
Fluorescence Molecular Tomography ◽  
Non Invasive ◽  
Early Tumor

AbstractPreclinical breast tumor models are an invaluable tool to systematically study tumor progression and treatment response, yet methods to non-invasively monitor the involved molecular and mechanistic properties under physiologically relevant conditions are limited. Here we present an intravital mesoscopic fluorescence molecular tomography (henceforth IFT) approach that is capable of tracking fluorescently labeled tumor cells in a quantitative manner inside the mammary gland of living mice. Our mesoscopic approach is entirely non-invasive and thus permits prolonged observational periods of several months. The relatively high sensitivity and spatial resolution further enable inferring the overall number of oncogene-expressing tumor cells as well as their tumor volume over the entire cycle from early tumor growth to residual disease following the treatment phase. Our IFT approach is a promising method for studying tumor growth dynamics in a quantitative and longitudinal fashion in-vivo.

Monitoring of chloride and activity of glycine receptor channels using genetically encoded fluorescent sensors

2008 ◽  
Vol 366 (1880) ◽  
pp. 3445-3462 ◽  
Author(s):  
Marat Mukhtarov ◽  
Olga Markova ◽  
Eleonore Real ◽  
Yves Jacob ◽  
Svetlana Buldakova ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Glycine Receptor ◽  
Yellow Fluorescent Protein ◽  
High Sensitivity ◽  
Functional Expression ◽  
Molecular Probes ◽  
Molecular Probe ◽  
Non Invasive ◽  
Spectroscopic Monitoring

Genetically encoded probes have become powerful tools for non-invasive monitoring of ions, distributions of proteins and the migration and formation of cellular components. We describe the functional expression of two molecular probes for non-invasive fluorescent monitoring of intracellular Cl ([Cl] i ) and the functioning of glycine receptor (GlyR) channels. The first probe is a recently developed cyan fluorescent protein–yellow fluorescent protein-based construct, termed Cl-Sensor, with relatively high sensitivity to Cl ( K app ∼30 mM). In this study, we describe its expression in retina cells using in vivo electroporation and analyse changes in [Cl] i at depolarization and during the first three weeks of post-natal development. An application of 40 mM K + causes an elevation in [Cl] i of approximately 40 mM. In photoreceptors from retina slices of a 6-day-old rat (P6 rat), the mean [Cl] i is approximately 50 mM, and for P16 and P21 rats it is approximately 30–35 mM. The second construct, termed BioSensor-GlyR, is a GlyR channel with Cl-Sensor incorporated into the cytoplasmic domain. This is the first molecular probe for spectroscopic monitoring of the functioning of receptor-operated channels. These types of probes offer a means of screening pharmacological agents and monitoring Cl under different physiological and pathological conditions and permit spectroscopic monitoring of the activity of GlyRs expressed in heterologous systems and neurons.

scholarly journals Direct focus sensing and shaping for high-resolution multi-photon imaging in deep tissue

2021 ◽  
Author(s):  
Jianan Qu ◽  
ZHONGYA QIN ◽  
ZHENTAO SHE ◽  
CONGPING CHEN ◽  
WANJIE WU ◽  
...  
Keyword(s):  
High Resolution ◽  
Adaptive Optics ◽  
High Sensitivity ◽  
Deep Tissue ◽  
Non Invasive ◽  
Mouse Cortex ◽  
Intact Brain ◽  
Resolution Imaging

High-resolution optical imaging of deep tissue in-situ such as the living brain is fundamentally challenging because of the aberration and scattering of light. In this work, we develop an innovative adaptive optics three-photon microscope based on direct focus sensing and shaping that can accurately measure and effectively compensate for both low- and high-order specimen-induced aberrations and recover near-diffraction-limited performance at depth. A conjugate adaptive optics configuration with remote focusing enables in vivo imaging of fine neuronal structures in the mouse cortex through the intact skull up to a depth of 750 um below pia, making high-resolution microscopy in cortex near non-invasive. Functional calcium imaging with high sensitivity and accuracy, and high-precision laser-mediated microsurgery through the intact skull were demonstrated. Moreover, we also achieved in vivo high-resolution imaging of the deep cortex and subcortical hippocampus up to 1.1 mm below pia within the intact brain.

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