Fluorescence microscopy relies on efficient emission of molecules excited by an incident laser light. However, their emission is often intrinsically limited by a low fluorescence quantum yield which results in low contrast images. In our recent efforts, we explored the fluorescence life-time imaging contrast for those low efficient fluorophores to find out that those molecules exhibit a rather intense emission over a relatively short time. This short fluorescence time was found to be dependent of the local structure and local environment providing a novel biomarker for biological imaging.
Chemotherapy is one of the treatment methods aimed at killing cancer cells and hindering their metastasis. However, chemotherapy is known to induce multiple adverse side-effects. One of them is peripheral neuropathy, which causes significant discomfort to the cancer patient. It is hypothesized that neuropathy is directly linked to peripheral nerve damage or elasticity change. In this study we have attempted to use Brillouin spectroscopy to evaluate nerve elasticity changes and correlate them to the effects of chemotherapy.
Ocular melanoma, albeit being rare, is an aggressive type of cancer, developing within the interior of a person’s eye. Location of this malignant growth increases severity of this type of cancer. It commonly develops in the middle layer of the eye, referred to as uvea. Melanoma develops from melanocytes, with a 90% of cases observed in posterior uvea (choroid). Complications from this type of cancer include metastasis in the liver. To avoid such outcome and improve treatments we are proposing application of fluorescence lifetime imaging microscopy (FLIM) to distinguish metastatic and non-metastatic melanomas. In the reported here preliminary study, we evaluate the system requirements for FLIM imaging of melanin-based tissues and structures.
SignificancePeripheral nerves are viscoelastic tissues with unique elastic characteristics. Imaging of peripheral nerve elasticity is important in medicine, particularly in the context of nerve injury and repair. Elasticity imaging techniques provide information about the mechanical properties of peripheral nerves, which can be useful in identifying areas of nerve damage or compression, as well as assessing the success of nerve repair procedures.AimWe aim to assess the feasibility of Brillouin microspectroscopy for peripheral nerve imaging of elasticity, with the ultimate goal of developing a new diagnostic tool for peripheral nerve injury in vivo.ApproachViscoelastic properties of the peripheral nerve were evaluated with Brillouin imaging spectroscopy.ResultsAn external stress exerted on the fixed nerve resulted in a Brillouin shift. Quantification of the shift enabled correlation of the Brillouin parameters with nerve elastic properties.ConclusionsBrillouin microscopy provides sufficient sensitivity to assess viscoelastic properties of peripheral nerves.
SignificanceThe vocal folds are critically important structures within the larynx which serve the essential functions of supporting the airway, preventing aspiration, and phonation. The vocal fold mucosa has a unique multilayered architecture whose layers have discrete viscoelastic properties facilitating sound production. Perturbations in these properties lead to voice loss. Currently, vocal fold pliability is inferred clinically using laryngeal videostroboscopy and no tools are available for in vivo objective assessment.AimThe main objective of the present study is to evaluate viability of Brillouin microspectroscopy for differentiating vocal folds’ mechanical properties against surrounding tissues.ApproachWe used Brillouin microspectroscopy as an emerging optical imaging modality capable of providing information about local viscoelastic properties of tissues in noninvasive and remote manner.ResultsBrillouin measurements of the porcine larynx vocal folds were performed. Elasticity-driven Brillouin spectral shifts were recorded and analyzed. Elastic properties, as assessed by Brillouin spectroscopy, strongly correlate with those acquired using classical elasticity measurements.ConclusionsThese results demonstrate the feasibility of Brillouin spectroscopy for vocal fold imaging. With more extensive research, this technique may provide noninvasive objective assessment of vocal fold mucosal pliability toward objective diagnoses and more targeted treatments.
Neurodegenerative diseases are currently among the most common causes for low quality of life among US population. In addition to that, disabilities caused by neurodegenerative diseases, negatively impact economy by causing early workforce retirement. Existing human models of such conditions are hard to replicate and describe due to the wide array of factors influencing the progression and morphology of the disease. Recent studies suggest application of photodynamically induced oxidative stress in drosophila model as a viable trigger to neurodegenerative conditions. We hypothesize that neural degradation is accompanied by significant changes in brain chemistry and biomechanics. This preliminary study focuses on investigation of correlation between drosophila brain elasticity and induced oxidative stress using combined Brillouin-Raman spectroscopy as a label-free method of elasticity measurement.
Poor recovery of peripheral neuron damage caused by trauma is currently among the most common causes for low quality of life among US population. Disabilities caused by neuron damage and poor recovery tend to cause early workforce retirement, creating a gap in skilled workforce in the US. Recent studies suggest that biomechanical vectors play an important role in nerve recovery and functionality restoration. This preliminary study focuses on investigating of correlation between biomechanical properties of murine sciatic nerve and Brillouin elasticity data. Combined Brillouin-Raman spectroscopy was used as a label-free method of elasticity measurement.
Recent advances in photodynamic inactivation and photobiomodulation require extensive research of application safety in living tissues in vitro and in vivo. Superficial phototoxicity induced cellular morphological changes have been observed and recorded with using confocal Brillouin microspectrometer. We are reporting evidence of biomechanical processes occurring in cells subjected to high-power laser radiation. 4T1 murine fibroblast cells were used in the study, making results easily after exposure to high power laser radiation. Spatial distribution of subcellular structures’ stiffness was recorded with high precision and analyzed, drawing correlation between existing morphological model and novel stiffness data within the cell.
Cancer remains among the leading causes of death in the United States. Early detection, classification and understanding of malignant cell proliferation and metastasis mechanisms are crucial for effective treatment. Current malignant cell studies largely rely on either invasive imaging techniques or invasive research protocols that hinder both speed and accuracy of cancer research. Here we are reporting successful imaging of cancer metastasis processes on a cellular level using Brillouin microspectroscopic imaging. In this research we are specifically presenting results of a non-invasive interrogation of elastic properties of 4T1 murine fibroblast cells in a spheroid model acquired with our custom-built confocal Brillouin microspectrometer. Spatial map of elastic properties was recorded for both interior and exterior regions of the 4T1 cell spheroid. We observed lower stiffness of cancer cells compared to cells from internal regions. In addition we observed the difference in stiffness values between cells exposed to challenging and normal environmental conditions. Our findings correlate well with prior published data, acquired with conventional biomechanical assessment techniques.
Antimicrobial photodynamic therapy (aPDT) in combination with antibiotics leads to a notable reduction in antibiotic minimum inhibitory concentration (MIC). Four antibiotic resistant bacterial strains (E. faecalis OG1RF(+), P. aeruginosa PA01, K. pneumoniae, E. coli ETEC) were evaluated with four antibiotics (ampicillin, kanamycin, tetracycline, chloramphenicol) in a combination treatment with methylene blue aPDT. Treatment involved co-culture of antibiotics with 1.0 μ𝑀 MB followed by exposure to 0 to 14.4 𝐽𝑐𝑚2 of light over 0 to 10 minutes at a rate of 30 𝑚𝑊𝑐𝑚2. MIC of test groups was compared to controls to evaluate direct effects on resistance, and further aPDT controls were used to evaluate measures of synergistic effect based on fractional inhibitory concentration index (FICI). It was found that 12 of 16 strain-antibiotic combinations have a reduction in antibiotic resistance during treatment, two of which are statistically significant. The calculated FICI values for these combinations contain 6 indifferent values between 1.0 and 1.5 and 10 additive values at or below 1.0, one of which was 0.43, qualifying as synergistic treatment. Overall, this survey provides a brief exploration of aPDT as an adjunct therapy for combatting antibiotic resistant bacteria. Further targeted research on strain-antibiotic combinations of interest may reveal valuable synergistic effects.
Raman spectroscopy is a powerful spectroscopic tool for remote and minimally invasive detection and chemical
identification of molecular species. Visible or infrared laser systems are often employed primarily due to their
great availability. Ultraviolet (UV) Raman spectroscopy offers several critical advantages over visible and infrared
systems, but is often limited by a high maintenance cost and low reliability of the laser system. We have
constructed a UV Raman spectroscopic system using a mercury capillary lamp with capabilities to capture
Raman spectra from 0 cm−1 to 4000 cm−1. The system’s low acquisition and maintenance cost, portability, high
sensitivity and specificity combined with minimal sample preparation make it ideal for the growing demands in
increased food quality and safety.
Cancer related deaths remain among the most common in the US with laryngeal cancer being among the most complicated to diagnose and treat. Most cancers in the larynx begin on the mucosal surface which yields cell morphology and biomechanical changes. Existing techniques that allow elastic properties measurements are incapable of achieving this goal in vivo. The main objective of a present study is to evaluate viability of Brillouin microscpectroscopy application to in vivo differentiation of various tissue types inside the larynx based on elasticity measurements. Here we are reporting successful application of Brillouin spectroscopy to characterization of postmortem porcine larynx’ Inferior Vocal Fold, Superior Vocal Fold, and Supraglottal Wall regions. Acquired data correlated well with previously reported results, indicating viability of Brillouin spectroscopy application to in vivo tissue imaging, morphological and mechanical characterization as a substitute for tissue biopsy.
Photodynamic inactivation (PDI) has been widely applied to localized infections, both internal and external. However, there is a notable knowledge gap when it comes to applying PDI to an entire organ system or even systemically throughout an organism. To study these treatment methods, an in vivo murine model of MHV-1 is planned. As a respiratory coronavirus, the model provides a suitable system for study, in addition to potential determination of systemic results. Specifically applied, MHV-1 has many key characteristics, such as symptoms and viral protein structures, that are in common or similar to other coronaviruses. Thus, this theorized model simultaneously addresses a key knowledge gap and provides useful insights into potential treatments for COVID-19 and similar disease-causing viruses. The risk of emergent viral threats and the necessity for rapidly developed, adaptable, affordable treatment methods are both now vividly evident.
Hydrogels have recently emerged as a promising material for broad range of biomedical applications including implantation, drug delivery and tissue engineering. New applications are driven by their unique physical and chemical properties making them chemically and mechanically biocompatible. In this report we assess non-invasive, nondestructive, and potentially high-throughput technique based on combined Brillouin / Raman spectroscopy and microscopy to interrogate hydrogels’ viscoelastic and chemical properties.
Deep Networks trained on one kind of data tend to perform poorly, on data that is beyond its training set. We believe this is because data sets tend to focus too directly on a specific task. We circumvent this by simulating various sinusoidal signal sums, with and without envelopes, along with blurred spike trains. We then add various noise to these signals during training to allow the networks to learn a denoising technique. Without using any real Raman or Brillouin data, our network successfully denoises and removes low frequency drifts from real experimentally acquired Raman and Brillouin data.
Brillouin microscopy is an emerging imaging modality in a broad area of biomedical research and clinical applications. Over the past decade, a significance progress has been achieved in developing better, more accurate and more user-friendly instrumentation for Brillouin microscopy and in fundamental understanding of the imaging contrast affordable in Brillouin microscopy. In this report, we report on our progress on developing advanced Brillouin microscopy imaging for imaging of dynamic biological processes.
This paper presents new high-performance optical-electronic scanner for security holograms authentication. Scanning speed is increased due to the use of sophisticated modern scanning systems, high-speed sensors and specifically designed and manufactured optical system components. Correlation filters used in the information processing decrease total processing time and increase resulting reliability of the authentication process.
Optically variable devices (OVD), otherwise called security holograms are widely used to protect IDs and other sensitive documents against counterfeiting. That being said, the problem of quick authenticity verification and quality control remain to be of utmost importance. This paper presents a prototype of the automated optical-electronic device for OVD authentication and quality control, as a complex solution. Developed device allows to conduct both quick preliminary hologram inspection, which is based on photometric image analysis, and in-depth hologram analysis. In-depth analysis implies microrelief parameters, like spatial frequency, relief depth, grating orientation measurements, using light intensity distribution in diffraction orders and the formed pattern of diffraction orders.
KEYWORDS: Holograms, Scanners, Information security, Optoelectronics, Optics manufacturing, Diffraction, Control systems, Reliability, Inspection, Process control
At present time, security holograms are widely used to protect against counterfeiting of various documents and identity cards. To control the security holograms authenticity on documents, devices that exclude the influence of the human factor and increase the speed and reliability of identification are needed. The paper presents an automatic optic-electronic scanner for operational control of security holograms authenticity on documents. The algorithm of data processing, operation principle of scanner and its design are described. The use of modern scanning systems, high-speed recording devices, specially designed and manufactured components of the optical system, as well as the use of correlation filters in the algorithm for recognizing the information received from the hologram, significantly reduce the time and raise the reliability of the security holograms authenticity control process.
Security holograms are widely used for anti-counterfeiting of banknotes, documents and consumer products. The development of automated devices for operative authentication and quality inspection of security holograms is still an actual task. There are several approaches to solving this problem. One of them is based on an image comparison of inspected and reference holograms. Also for quality inspection of security holograms, the methods based on direct and indirect measurements of microrelief parameters are used. In this article we present a complex solution for automated quality inspection and authentication of security holograms.
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