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Multiplex Coherent Anti-Stokes Raman Scattering (M-CARS) is an innovative nonlinear spectroscopic approach designed to characterize the vibrational modes of molecular structures. Coherent Raman scattering has been used for the characterization of biomedical targets for about 20 years and the multiplex aspect was introduced 10 years ago thanks to the use of a supercontinuum laser system. For each of these systems, the combination of a pump and a probe wave, driven by an external delay line, is however required to produce the vibrations. In the present work, we propose a new M-CARS system, free of the external delay line. A few-mode microstructured fiber enables merging both wave-packets (pump and supercontinuum) within a single waveguide. We showcase the capability of this system in generating hyperspectral images of biochemically active compounds. Curcumin I, the principal yellow compound isolated from Curcuma longa (Turmeric), is distinguishable by its multiple functional groups that display a nonlinear spectroscopic behavior.
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We've established a nonlinear multimodal imaging system that incorporates stimulated Raman Scattering (SRS), multiphoton fluorescence (MPF), and second harmonic generation (SHG) to explore the connections between metabolic activities and the distribution of metabolites in cells and tissues. Furthermore, we've devised the Adam-based Pointillism Deconvolution (A-PoD) and Correlation Coefficient Mapping (CoCoMap) algorithms, enabling a deeper insight into the simultaneous recording and regulation of various metabolic processes within super-resolved images of nanoscale Regions of Interest (ROIs). In our pursuit of specifically identifying signals originating from distinct subcellular organelles, we've introduced a pioneering clustering algorithm known as Multi-SRS reference matching (Multi-SRM). This approach has the potential to improve early disease detection, prognosis, the evaluation of therapeutic effects, and our comprehension of the mechanisms underpinning aging and biomedicine.
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Aging related biological mechanisms are often difficult to probe in situ without exogenous fluorophores. Here, we leverage label-free stimulated Raman scattering (SRS) microscopy to provide new insights into aging in C. elegans. We demonstrate multispectral SRS imaging of whole worms in vivo with quantitative chemical insights across different ages. We show that both lipid and protein synthesis and compartmentalization are associated with aging in worms. We additionally use SRS in combination with simultaneous two-photon fluorescence imaging to characterize the putatively aberrant protein accumulation. Moreover, we observe notable SRS image differences when worms are subjected to calorie restriction, suggesting a promising avenue towards understanding calorie-restriction’s enhancing effects on longevity when coupled to proteomic and metabolomic analysis.
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Implant associated infections can result in inflammatory conditions such as periimplantitis, that can ultimately lead to implant loss. This is caused by a large community of bacterial species. These bacteria form a multispecies biofilm on the tooth surface. Its composition can shift as it matures over time, the so-called pathogenic shift occurs once pathogens adhere to the biofilm.
We developed a measurement protocol and analysis pipeline based on ATR-FTIR spectroscopy that is able to distinguish between different oral bacteria by detecting slight changes in protein expression. This can easily be done for single species samples with supervised learning algorithms like the k-nearest neighbour algorithm, with which we achieved a prediction accuracy of 99.8 %. Chemometric and deep learning approaches can streamline the process in distinguishing multispecies samples. This would be a step towards early detection of the pathogenic shift in oral biofilms and help avoiding diseases.
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Osteoarthritis (OA), a degenerative joint disease presenting as loss of cartilage, is a leading cause of disability worldwide, increasingly with aging populations. Early detection is crucial for effective treatment since there is no definitive cure, yet, current assessment techniques fall short and rely on ionising radiation or invasive procedures. We report an application of multimodal “spectromics”, low-level abstraction data fusion of non-destructive NIR Raman and NIR-SWIR absorption spectroscopy, providing an enhanced, interpretable “fingerprint” for diagnosis of OA in human cartilage. Under multivariate statistical analyses and supervised machine learning, cartilage was classified with high precision and disease state predicted accurately. Discriminatory features within the spectromics fingerprint elucidated clinically relevant tissue components (OA biomarkers). Further, we have developed an automated goniometric 3D hyperspectral mapping setup, and characterised OA cartilage on whole human femoral heads post hip arthroplasty for spatially-resolved spectromics. These results lay foundation for minimally invasive, deeply penetrating, label-free, chemometric diagnosis of the hip.
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Heart Failure with Preserved Ejection Fraction (HFpEF) is a severe medical condition. Concurrent pathologies linked with HFpEF create a complex scenario that contributes to structural and functional abnormalities in the heart and kidneys—the principal end organs affected by HFpEF. In this study, we assessed the effectiveness of a synergistic application of FTIR and Raman spectroscopy and multivariate/univariate statistical analyses to yield valuable pathophysiological insights in a rat model of heart failure. Peculiar biochemical differences were detected in the two organs demonstrating heightened sensitivity of these techniques towards the distinctive HFpEF phenotype.
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Atopic dermatitis (AD) and psoriasis are the two most prevalent skin disorders, often assessed through subjective questionnaires or visual evaluations conducted by clinicians, which can be subject to interpersonal variations. This study aims to explore the distinctions between these skin conditions and healthy skin using a portable confocal Raman spectroscopy (CRS) system for objective assessment. Spectral measurements at 671 nm and 785 nm on 9 AD, 6 psoriasis, and 11 healthy subjects reveal lower water content in AD compared to psoriasis and healthy skin. Ceramide subclasses show disease-specific trends, distinguishing AD, and psoriasis. Cholesterol levels further differentiate these conditions, with lower concentrations in lesional AD and significantly higher concentrations in lesional psoriasis compared to healthy skin. These differences contribute to the objective differentiation of skin conditions aiding in thorough assessment and treatment monitoring. Furthermore, it offers valuable insights for developing targeted disease-specific topical treatments.
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We present a compact and portable stimulated Raman scattering (SRS) imaging system capable of high speed, label-free imaging of cells and tissues. Our setup rapidly acquires multispectral datasets with high chemical specificity by scanning the spectral range of 700-3100 1/cm in just 100 ms, providing a tenfold increase in acquisition speed. It allowed to visualize cell nucleus and cytoplasm changes during drug induced cancer cell death. SRS offers distinct advantages, providing valuable insights into drug-cell interactions, cell morphology, and chemical changes without the interference of exogenous labels. The novel high-speed SRS systems allows rapid screening of drug effects on cancer cells.
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Compressive Raman imaging has emerged as a promising technique to speed up chemical imaging by compressing the data during acquisition. Yet, current scanning imaging speed is fundamentally limited by the sensors pixel dwell times of at best 1µs. Here, we introduce a compressive Raman spectrometer layout equipped with a novel parallelized spatial acquisition using a single-photon avalanche detector array. We show imaging with pixel dwell times of <10µs using the otherwise weak spontaneous Raman effect, thereby unlocking video-rate imaging.
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Studying fiber architectures in tumor tissues is of great importance as the cancer cells interact with fiber structures in the Extracellular Matrix (ECM). Computational Scattered Light Imaging (ComSLI) represents an innovative, non-destructive approach to whole-slide imaging with micrometer resolution, uniquely capable of accurately unraveling the complex, intertwined fiber structures in biological tissues. So far, it has been mainly used to study highly interwoven nerve fiber architectures in brain tissues. In this study, we extend the application of ComSLI to visualize fibers in diverse tumor tissues, including oral squamous cell carcinoma (OSCC) and colorectal cancer.
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Precision and stability in confocal microscopy are vital for maintaining image clarity and preventing misinterpretation of radiometric fluctuations as changes in fluorescence intensity within the sample. This study discusses a focus variation induced by an 810-nm continuous wave laser integrated into the optical path of an inverted confocal microscope with a 60x oil immersion objective. Activation or deactivation of the laser leads to a drift in the focus position towards lower or higher values of the vertical coordinate z, respectively. The maximum observed drift is 2.25 μm, occurring with a 40 mW laser power at the sample over a 600-second exposure time. The temporal behavior of the focus position follows exponential curves resembling temperature fluctuations associated with a heat source. Our analysis strongly indicates that the focus drift is attributable to the heating of the immersion oil.
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We present a new architecture for frequency-modulation stimulated Raman Scattering (FM-SRS) that allows broadband background-free acquisitions. The system is based on a femtosecond laser oscillator (Stokes beam), used to pump a narrowband picosecond optical parametric oscillator (pump beam). Using an electro-optic modulator and polarizing beam splitter, we separate the broadband Stokes beam into two intensity-modulated Stokes beams that are spectrally filtered using a high-speed, narrowband acousto-optic tunable filter (AOTF) and a narrowband etalon. The two Stokes sub-beams and the pump beam are then recombined. By detecting the signal as the difference between in-Raman-resonance and off-Raman-resonance wavenumbers, we achieve background-free SRS measurements. Our scheme significantly simplifies and gives flexibility in selecting the pair of wavenumbers for FM-SRS, and allows background-free acquisitions from the fingerprint to the CH-stretch region of the Raman spectrum.
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A promising alternative ultrasound detection scheme in photoacoustic imaging is the use of an optical camera to achieve massively parallelized data acquisition. For this purpose, the millions of pixels of common CMOS- or CCD-cameras are used to capture ultrasound-induced intensity modulations of a light field. Depending on the interaction mechanism in the propagation medium or at an interface, either projections or sectional images of the pressure field are recorded directly by means of free beam propagation or indirectly via optical fibers at certain times of wave propagation. Here we present the functionality of different experimental implementations and discusses their advantages and disadvantages in terms of achievable sensitivity, bandwidth, data structure, image acquisition rate, suitability for multimodal imaging, compactness of the implementation and gives an outlook on future new developments in this direction.
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Conventional photoacoustic (PA) imaging suffers from visibility artefacts due to limitations in ultrasound transducer bandwidth, viewing angles, and the use of sparse arrays. PA fluctuation imaging (PAFI), exploiting the signal changes due to blood flow, compensates for these artefacts, at the cost of temporal resolution.
Our study addresses this limitation employing a deep learning approach in which PAFI images serve as ground truths for training a 3D neural network to obtain real-time single-shot artefact-free images.
Following a pre-training with simulated examples, a 3D-ResUnet network was trained with 90 PA chicken embryo vasculature volumes as input and corresponding PAFI as ground truths. Notably, inclusion of experimental data significantly improves predictions over simulation-only training, even accounting for transducer angular filtering.
Furthermore, applying the same network exclusively trained in-ovo to predict the femoral artery in mice demonstrates the potential of this method for real-time, full-visibility multispectral PA imaging in vivo using sparse arrays.
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Fabry-Perot tomographs have captured compelling photoacoustic images as they combine small element sizes with high acoustic sensitivity and a broad frequency response. A photoacoustic tomograph based on a sCMOS camera and a Fabry-Perot sensor with uniform optical thickness was developed. The influence of camera parameters on the e.g., spatial distribution of the acoustic sensitivity was evaluated. The imaging capabilities were demonstrated by capturing images of PA phantoms.
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The development of photoacoustic contrast agents relies on the recovery of the photophysical properties from cuvette measurements. Photoacoustic signals are typically described using the Beer-Lambert law. In contrast agents with long excited state lifetimes, it is no longer valid. This is particularly noticeable at low concentrations and short cuvette pathlengths as acoustic propagation and detection effects become significant. A forward model is used to calculate time-resolved signals generated in a cuvette. The model is fitted to measured signals to recover absorption coefficients. The model will enable the characterization of new contrast agents by recovering the spatial distribution of thermalized energy.
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Three-dimensional quantitative photoacoustic tomography (3D-QPAT) aims to recover tissue chromophore concentrations from multispectral images but is often hampered by the unknown light fluence and the transfer function of the scanner. Inversion schemes that use hybrid light transport and acoustic propagation models may be used to address this challenge. While model-based inversions have shown promising results in in silico and tissue phantom studies, limitations in accuracy arose from limited view artefacts. This study evaluated reconstruction methods such as time-reversal, maximum a posteriori, iterative least square and total variation to improve the accuracy of 3D-QPAT inversion techniques.
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Optical coherence elastography (OCE) is an imaging technique capable of mapping mechanical properties (such as elasticity) in 3-D and is emerging as a valuable tool in the study and potential intraoperative diagnosis of breast cancer due to mechanical contrast between healthy and malignant tissue. While the correlation between elevated elasticity in OCE and breast cancers has been well established, these studies have primarily focused on binary classifications of tissue as either malignant or benign, ignoring much of the heterogeneity present in breast tissue. In this work, we present a detailed assessment of the microstructures present in human breast tissue images acquired with OCE, identifying regions of interest that corresponded to invasive carcinomas, in situ carcinomas and benign tissue types. We also describe the unique morphological patterns present in each tissue type and provide a framework for the interpretation of breast cancer images acquired with OCE.
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We quantify the precision and bias of dynamic light scattering optical coherence tomography (DLS-OCT) measurements of the diffusion coefficient and flow speed for first and second-order normalized autocovariance functions. For both diffusion and flow the measurement precision and accuracy are severely limited by correlations between the errors in the normalized autocovariance function. We demonstrate a method of mixing statistically independent normalized autocovariance functions at every time delay for removing these correlations. The mixing method reduces the uncertainty in the obtained parameters by a factor of two but has no effect on the standard error of the mean. We find that the precision in DLS-OCT is identical for different averaging techniques, but that the lowest bias is obtained by averaging the measured correlation functions before fitting the model parameters. With our correlation mixing method it is possible to quantify the precision in DLS-OCT and verify whether the Cramer-Rao bound is reached.
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This study investigates the relationship between Pannexin 1 and refractive errors using a custom-made 1310nm OCT system, capable of imaging the whole eye. Prior research reported vision-related issues in Panx1 mutants but lacked insights into underlying mechanisms. Obtained OCT results establish a direct link between Pannexin1 (Pannexin 1a, Pannexin 1b, and Panx1DKO) and eye structure alterations, primarily manifesting as axial length elongation and negative RRE values, indicating myopia. Additionally, whole eye OCT imaging identifies several category of defects in the lens epithelium and aphakia. This research underscores Pannexin1's significance in visual system development and refractive errors, further emphasizing the diagnostic potential of optical coherence tomography in ophthalmology. Leveraging zebrafish as a model organism offers a unique opportunity to investigate genetic and cellular mechanisms influencing eye health, advancing our understanding of genetic factors and paving the way for further research and potential therapeutic interventions in the field of ophthalmology.
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Optical diffraction tomography (ODT) is a powerful 3D imaging technique with immense potential in fields like cancer diagnosis and drug treatment. However, traditional ODT systems face limitations like the "missing cone" problem, affecting 3D resolution and cancer classification. To address this, fiber-optic dual-beam technology employs controlled laser beams for stable cell rotation, improving tomographic imaging. This improvement is further enhanced by a novel tomographic workflow that incorporates optical flow and deep learning, replacing manual interventions with automated processes. This novel method is validated by reconstructing 3D images of simulated cell phantoms, HL60 human cancer cells, and artificial cell phantoms. Its adaptability extends to diverse imaging techniques, promising advancements in cell biology, innovative therapeutics, and enhanced early-stage cancer diagnostics.
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Forces inside cells play a fundamental role in cell behavior, for example in cancer cell migration. We focus on the vinculin protein which is involved in the stabilization of cell adhesion.
Through fluorescence transfer (FRET), forces within vinculin can be measured with picoNewton sensitivity. We measure these internal forces while applying a calibrated external force with a laser-based optical tweezer via a microbead attached to the cell.
Our most recent results using fibroblast cells show that the force applied with the optical tweezer induces the recruitment of vinculin and the formation of focal adhesions on the bead within a few minutes. Once the bead is attached to the cell, we record its trajectory and infer the force exerted by the cell. We correlate this force with the FRET efficiency of the force sensor.
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In neuroscience, two photon scanning microscopy is commonly used to record brain activity in species that differ greatly in brain size and their properties and distributions of neurons. Accordingly, tailoring the properties of the imaging system to the experimental model in question is critical. These include adjustments in the size of the field-of-view, the shape and curvature of the scan-plane, or adjustment in excitation PSF sizes. Here, we report our progress to optimising these and other imaging parameters for high-signal-to-noise imaging of whole-brain neuronal activity in the large nervous system of Xenopus laevis tadpoles with comparable quality compared to what is currently possible in juvenile zebrafish.
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We explore the application of structured vortex laser beams, or shaped light with orbital angular momentum (OAM), in the diagnosis of cell and cell cultures and the quantitative characterization of biological tissues. To examine the conservation of spin and orbital angular momenta during propagation, we constructed a Mach-Zehnder-like interferometer, equipped with a spatial light modulator (SLM), to generate Laguerre-Gaussian (LG) beams with varying momenta. As the LG beam traverses tissue samples, its interference with a reference plane wave is captured by a camera. Our findings reveal that the OAM of the LG beam is maintained through both normal and cancerous tissue samples, exhibiting a distinct phase shift – or twist of light – which is significantly more sensitive (up to ~1000 times) to changes in the tissue's refractive indices compared to conventional methods. We conclude that leveraging OAM in biomedical diagnosis presents exciting prospects for both groundbreaking biological research and enhanced clinical applications.
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This study analyses the pH-dependent time resolved fluorescence of mCardinal and mNeptune, two red-shifted fluorescent proteins with applications in biomedical imaging. We utilized molecular dynamics (MD) simulations to illuminate the influence of water molecules on the proteins´ photophysical properties.
In mCardinal, the average fluorescence lifetime markedly rises from 0.95 ns at pH 7.0 to 1.25 ns at pH 5.5. Conversely, mNeptune exhibits a constant fluorescence lifetime, showing no pH sensitivity.
Through Decay-Associated Spectra and MD simulations, we correlated mCardinal’s pH-induced lifetime changes with its molecular properties. Despite both proteins being equally stabilized by hydrogen bonds, mCardinal’s chromophore formed more water contacts than mNeptune’s. Additionally, the chromophore’s interactions with specific amino acids varied between the two proteins, suggesting distinct differences in the excited state proton transfer as a crucial mechanism for pH sensitivity.
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Infectious diseases are a major cause of human mortality and have also a huge impact on agriculture. Optimal methods to detect them would be non-invasive and without extensive sample-taking/processing. We developed a set of near infrared (NIR) fluorescent nanosensors and used them for remote fingerprinting of clinically important bacteria/viruses and to detect pathogen responses in plants [1,2,3]. The nanosensors are based on single-walled carbon nanotubes (SWCNTs) that fluoresce in the NIR optical tissue transparency window. To identify bacteria relevant for humans they were chemically tailored to detect released metabolites as well as specific virulence factors (lipopolysaccharides, siderophores, DNases, proteases) and integrated into functional hydrogel arrays with different sensors. These hydrogels are able to distinguish important bacteria (Staphylococcus aureus, Escherichia coli, …) by NIR imaging. Similar sensors allowed us to visualize the chemical defense of plants in response to pathogens and to detect the corona virus. In summary, such nanosensors in combination with NIR imaging concepts demonstrate huge potential for precise monitoring of pathogens.
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Numerous biological surfaces exhibit intricate micro- and nano-structures, which fulfill various functions such as anti-reflective properties, structural coloration, anti-fouling capabilities, and pro- or anti-adhesive characteristics. These features have inspired a plethora of industrial applications. In recent years, there has been a significant surge in research in this domain, largely attributable to the growing interdisciplinary nature of the approaches applied to the investigation of structured biosurfaces.
The convergence of classical zoology and botany with advances in genetics and molecular biology is noteworthy, as biologists increasingly collaborate with nanotechnologists, materials scientists, and engineers. This collaborative effort contributes significantly to expanding the horizons of research on micro- and nano-structured biological surfaces, fostering biomimetic and bioengineering applications in various industries (Fig.1). Our proposal seeks to capitalize on this momentum and align with the current developments in the field.
The primary objective of the COST Action titled "Understanding interaction light – biological surfaces: possibility for new electronic materials and devices" is to unite scientists from diverse disciplines within this dynamic research realm. The emphasis of this collaborative effort is placed on exploring the photonic effects arising from the nano- and micro-structuring of biological surfaces, along with their potential bionic applications. Through our consortium, we aim to facilitate cross-inspiration among participants from distinct research fields, fostering an environment conducive to innovation in research and eventual industrial advancements. Our initiative seeks to ride the wave of these scientific developments, propelling forward the exploration of the intricate world of micro- and nano-structured biological surfaces.
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We present a investigations of dental ceramics using in-house developed swept source (SS) optical coherence tomography (OCT) systems. The issue is related to the loss of calibration of ovens utilized for the fabrication of dental crowns. In the first study [http://dx.doi.org/10.3390/app7060552], metal-ceramics crowns were manufactured, in five study groups, with five maximum sintering temperatures: a normal one, two lower levels and two upper levels (up to +50ºC with regard to normal). OCT B- and C-scans were obtained, and qualitative rules-of-thumb were extracted to assess the oven temperature level by observing ceramic grains bellow the level of the tooth-shaped crowns. The second study [https://doi.org/10.3390/ma12060947] moved to a quantitative assessment of the calibration loss of the ovens. A second type of material (for all-ceramic crowns) was considered, and three levels of its specific temperature were tested. For both ceramics reflectivity curves were obtained from OCT C-scans. These analyses demonstrated that there is (only) one parameter consistent with the shift of the maximum temperature in the oven: the ratio of the maximum and minimum (filtered) reflectivity.
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Design and synthesis of photosensitive 1D photonic system based on cholesteric liquid crystalline polymer will be presented. The photosensitivity and chirality is provided by a novel chiral hydrazone photochromic moiety covalently boud to the polymer backbone of a comb-shaped copolymer. Combination of the chirality and photosensitivity enabled reversible photomanipulation of the helical pitch of the supramolecular cholesteric structure resulting in material with a tunable selective reflection of circularly polarized light of the same helical sense as the chiral structure. In contrast to many other photochromic systems based on E-Z isomerization, the E and Z isomers of hydrazone photochromic group are kinetically stable that enable to achieve a pure photoinduced switch without any dark relaxation at any temperatures
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Biological discovery is a driving force of biomedical progress. With rapidly advancing technology to collect and analyze information from cells and tissues, we generate biomedical knowledge at rates never before attainable to science. Nevertheless, conversion of this knowledge to patient benefits remains a slow process. To accelerate the process of reaching solutions for healthcare, it would be important to complement this culture of discovery with a culture of problem-solving in healthcare. The talk focuses on recent progress with optical and optoacoustic technologies, as well as computational methods, which open new paths for solutions in biology and medicine. Particular attention is given on the use of these technologies for early detection and monitoring of disease evolution. The talk further shows new classes of imaging systems and sensors for assessing biochemical and pathophysiological parameters of systemic diseases, complement knowledge from –omic analytics and drive integrated solutions for improving healthcare.
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Development of optical quality bioresorbable fibers is an emerging area of study where researchers are trying to advance the field by assessing the suitability of these fibers for various biomedical applications. These types of fiber implants dissolve in the human body over a clinically relevant time scale eliminating the need for extraction surgeries.
We conducted both ex-vivo and in vivo diffuse correlation spectroscopic studies using our fibers to measure blood flow and a preliminary trial to integrate a biocompatible electrode material on the fiber for electrical signal measurements. The results demonstrated the potential of Calcium Phosphate glass-based fiber-optic devices in future physiological monitoring applications which can be implanted inside the body without the need of an explant procedure.
Acknowledgement: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 860185.
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This conference presentation was prepared for SPIE Photonics Europe, 2024.
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Stem cell therapy holds tremendous potential for treating a wide range of currently incurable diseases, including retinal degenerations and geographic atrophy from macular degeneration. This study aimed to develop a non-invasive multimodality imaging system to track stem cells after transplantation in the subretinal space. Human-induced pluripotent stem cells differentiated to retinal pigment epithelium (hiPSC-RPE) cells were labeled with ultraminiaturized gold nanochains. The labeled hiPSC-RPE cells were then injected into 21 rabbits at 4 days after laser-induced photocoagulation damage to the RPE. Color fundus photography, photoacoustic microscopy, optical coherence tomography and fluorescent imaging were used to monitor the rabbit retina before and after the transplantation. The migration pattern and viability of the cells were monitored up to 6 months with a 37-fold increase in 650nm PAM signal. This approach allowed for the longitudinal evaluation of location of the transplanted stem cells, providing valuable insights for the advancement of stem cell therapies.
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Tissue histopathology, reliant on costly and time-consuming hematoxylin and eosin (H&E) staining of thin tissue slices, faces limitations. Label-free non-linear optical microscopy in vivo presents a solution, allowing work on fresh samples. Implantable microstructures prove effective for systematic longitudinal in vivo studies of immunological responses to biomaterials using label-free non-linear optical microscopy. Employing two-photon laser polymerization, we implanted a matrix of 3D lattices in the chorioallantoic membrane of chicken embryos, establishing a 3D reference frame for cell counting. H&E analysis is compared to label-free in vivo non-linear excitation imaging for cell quantification and identifying granulocytes, collagen, and microvessels. Preliminary results in higher animal models demonstrate the transformative potential of this approach, offering an alternative to conventional histopathology for validating biomaterials in in vivo longitudinal studies.
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Imaging a large number of samples is necessary to improve statistical robustness in biological assays. Using standard multiwell plates is not possible in usual light-sheet microscopes. One solution is to use an Oblique Plane Microscope (OPM), which is a special fluorescence light sheet microscope, with a single objective near to the sample. To avoid aberrations, OPM generally uses water or silicon immersion to match the refractive index of the sample. In this work we present an oil-immersed OPM and experimentally demonstrate the possibility of using a primary objective with a higher numerical aperture.
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We demonstrated the application of wavenumber-dependent DLS-OCT to measure both collective and self-diffusion coefficients in concentrated silica suspensions. Depending on the sample polydispersity, we successfully measured either long-time collective or long-time self-diffusion over a broad q-range using our custom-built OCT system. The measured collective diffusion coefficient shows excellent agreement with hard-sphere theory, providing further evidence for the dynamic scaling property. It also serves as an effective tool for accurately determining particle sizes in concentrated suspensions. We found the decoupling approximation to be highly effective in describing the first-order normalized autocovariance functions in both monodisperse and relatively polydisperse samples.
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In this work, we present two approaches for Broadband coherent anti-Stokes Raman spectroscopy (BCARS) imaging for biomedical research applications. The first approach is optimized for fast microscopy. The setup combines a chirped pulse amplification laser with the generation of supercontinuum generation in YAG crystal and PCF fibers. The second approach uses a fiber-based optical parametric amplifier to enable fast-tuned narrow-band pulses for fast hyperspectral multi-modal image acquisition in endoscopy settings.
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Diagnostic Raman spectroscopy offers a rapid approach for pathogen detection and phenotypic antimicrobial susceptibility testing. Following isolation, two common bloodstream infection bacteria, Escherichia coli and Staphylococcus aureus, were treated with appropriate antibiotic concentrations and analyzed using On-Chip Raman spectroscopy. Using photonic data analysis, the spectral signals are translated into antibiograms.
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Various biological surfaces are known to be covered by elaborated micro- and nano-structures, serving a number of functions (e.g. anti-reflective, structural coloration, anti-fouling, pro- or anti-adhesive, etc.) and inspiring numerous industrial applications. Recent years have witnessed a remarkable boost in research in this field. To a large extent, this boost owes to the increasing interdisciplinary of approaches being applied to the study of structured biosurfaces. Sciences as different as classical zoology and botany are inseminated with the advances in genetics and molecular biology; biologists collaborate more and more with nanotechnologists, materials scientists and engineers – all these contribute to the widening of the horizons of research on micro- and nano-structured biological surfaces, and to biomimetic and bioengineering applications of these surfaces in industry. We aim at ‘riding the wave’ of these developments with our proposal. In our talk I will present the main goal of the COST Action “Understanding interaction light – biological surfaces: possibility for new electronic materials and devices”.
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