Infectious diseases threaten the health of people. The rapid identification of infectious pathogens together with the characterization of their interaction with drugs is crucial for the patient’s survival. Classical microbiological analysis methods rely on time-consuming cultures. Raman spectroscopy together with chip-based sampling strategies offers the potential to bypass time-consuming cultivation and allows for a rapid characterization of microbial pathogens on a single cell level. It will be shown that Raman spectroscopy holds great promise as point-of-care-approach for a rapid monitoring of bacteria in body liquids or for water-, air- and soil monitoring and for the detection of pathogens in food.

We present the development of a cost-effective, sensitive and specific diagnostic methodology to improve the reliability of the cytopathology diagnosis. The methodology will be based on a new cytology protocol where immunolabeling is performed on fresh cells before fixation using spectrally distinctive plasmonic NPs conjugated with antibodies as optical biomarkers. The methodology includes a new multispectral and hyperspectral dark-field microscopy for reliable multiplexed and quantitative immunoplasmonic markers detection. The unique optical properties of plasmonic NPs provide new opportunities for multicolor imaging and multiplexed immunolabeling due to the very distinctive NPs chromatic signature that depends on their composition, size, and geometry.

In this study, we investigate the potential of altered breathing patterns as a technique to assess localized oxygenated perfusion in DFUs as a measure of healing potential. Subjects were imaged at discrete time points and dynamically to measure the relative oxy- (ΔHbO) and deoxyhemoglobin (ΔHbR) changes in normal and DFU scenarios. Results indicate that under normal circumstances, oxygenated perfusion changes are consistent and uniform at all points of the foot as opposed to the DFU scenario’s inconsistent oxygenated perfusion. Altered breathing paradigms may serve as a useful tool in assessing localized sub-surface oxygenated perfusion in regions around the wound.

A near-infrared optical scanner (NIROS) that performs non-contact NIR spectroscopic imaging to provide 2D tissue oxygenation maps of the entire wounds has been developed. Herein, a semi-automatic image segmentation and co-registration approach using machine learning has been developed to differentiate regions of changed tissue oxygenation. The developed image analysis approach was validated via phantom and in-vivo studies on controls, demonstrating an accuracy >97%. The technique was further implemented on wounds (here, diabetic foot ulcers) across weeks of treatment. Regions of decreased oxygenation were demarcated, and its area estimated and co-registered in comparison to the clinically demarcated wound area.

Polarized Raman Spectroscopy characterize the symmetry of the bond vibration of bio molecules with the chemical information compared to conventional RS, as it mainly exhibit the isotropic nature .Using this technique , the blood plasma and tissues of normal and cancer subjects were taken up for this study. Observed the variations in the Amide I, II and Amide III regions by calculating the depolarization ratio , from which we could understand the changes occurring in peptide bond and secondary structure of protein due to malignancy ..The results were appreciable, in discriminating the cancer from normal subjects using Polarized Raman spectroscopy.

Increased lipid accumulation has been observed in multiple types of aggressive cancer cells, but the composition of these lipid droplets remained unclear. This study observed an aberrant accumulation of cholesteryl ester in metastatic lesions using Raman spectroscopic analysis of lipid droplets in human prostate cancer patient tissues. Depletion of cholesteryl ester storage significantly suppresses the development and growth of metastatic cancer lesions in prostate cancer orthotopic and intra-cardiac injection mouse models with negligible toxicity. Gene expression profiling reveals that cholesteryl ester depletion suppresses the metastatic potential through upregulation of multiple regulators that negatively impact metastasis. Additionally, Wnt/β-catenin, a vital pathway for metastasis, is downregulated upon cholesteryl ester depletion. Mechanistically, inhibition of cholesterol esterification significantly blocks secretion of Wnt3a through reduction of monounsaturated fatty acid levels, which limits Wnt3a acylation. These findings open opportunities for diagnosing and treating metastatic prostate cancer by targeting the altered cholesterol metabolism. These preclinical results pave the foundation for further clinical studies.

Optical spectroscopic techniques based on tissues, cell lines and biofluids for the detection of cancer and various disorders are being extensively opted due to their high sensitivity, ease of procedure and sample preparation. Though the use of fluorescence in the field of oncology started as early as 1924 by Policard et al, the use of Native Fluorescence Spectroscopy (NFS) as a tool for cancer diagnosis and treatment monitoring, has shown significant progress only in the recent years, due to the advancements in the detection system and software. Even though an array of chemotherapeutic agents and sophisticated Radiotherapy techniques have evolved in the management of cancers, surgery is mostly opted as the first line of treatment in most of the breast cancer cases, in an approach to remove the bulk of a tumour from the body. The goal of this study is to assess the efficacy of various treatment modalities, in this case, surgery (modified radical mastectomy) and chemotherapy by comparing the NF spectra of breast cancer patients, post-surgery with those on completion of chemotherapy and normal subjects. In this pilot work, NF spectroscopy of blood plasma of clinically confirmed 43 breast cancer patients was measured under pre-treatment, post-surgical, post chemotherapy and also during yearly follow-up (after completion of the entire treatment) conditions. The NFS spectra of 60 normal subjects were also recorded for comparison. The results indicate that there is a statistical significance in the spectral variations in the region of collagen, elastin and NADH between the normal and cancer patient’s blood plasma as well as between pre and post-treated cases as well as those patients on yearly follow-up after completion of the entire treatment.

Metabolic dynamics is essential to unraveling the mechanistic basis of many biological processes, and cannot be imaged in vivo by using traditional methods. Here we developed a new method that combines D2O probing and SRS (DO-SRS) to visualize metabolic dynamics in live animals. The enzymatic incorporation of D2O-derived deuterium (D) into biomolecules will generate carbon-deuterium (C-D) bonds in macromolecules. We developed spectral unmixing methods to obtain C-D signals with macromolecular selectivity, and applied DO-SRS to reveal metabolic dynamics in C. elegans, zebrafish, and mice, to study developmental biology, aging, and tissue homeostasis, and to visualize tumor boundaries and metabolic heterogeneity.

In this talk, a brief overview on the non linear and linear laser brain imaging techniques will be displayed both for label free and specific labeling detection. Morpho-functional characterization of tissue will be displayed as an interesting tool for early diagnosis of pathologies: different kind of approaches will be shown for in vivo imaging assisted surgery operation or as tools to support anatomo-pathologists decision. For example, several techniques, useful to create a new 3D histological analysis also on cleared tissue will be shown. Furthermore, particular attention will be devoted to the big data managing strategies adopted to extract some quantitative parameters, like cell census, by using some deep learning approaches.

The hemodynamics and oxygen saturation status of vascular are very important biomarkers for disease, such as brain glioma tumor and ischemia-reperfusion ulcer. Therefore, a high spatial resolution imaging tool for vascular imaging is demanded. Conventional optical imaging modalities, including confocal microscopy and two-photon microscopy, require external contrast agent to image blood vessels and are not sensitive to oxygen saturation. In this paper, we introduce a dual-wavelength optical-resolution photoacoustic microscopy (OR-PAM) system for functional imaging of vasculature. This system has demonstrated its application in brain glioma tumor imaging, as well as skin ischemia-reperfusion imaging.

Photoacoustic spectroscopy (PAS) and imaging have attracted much research attention over the past few decades for various applications. These technologies have not yet appeared in many commercial applications. The key production challenge with a spectroscopic technique is in the hardware integration - optical and acoustic components integrated on the same platform. With the growing demand for medical diagnostic sensors at point-of-care, various lab-on-chip systems are being developed that rely on electrical impedance, fluorescence, Infra-red and Raman spectroscopy for analyzing the test samples. However, purely optical methods end up paying a significant penalty in the accuracy of spectral discrimination and quantification due to photon scattering. Additionally, many lab-on-chip analytes are in different states of gel, amorphous powders, cells, molecules etc., making it difficult to quantify using conventional reflective and transmissive optical methods alone. There is a need to develop an on-chip CMOS compatible architecture to commercialize the photoacoustic technology and leverage its benefits for lab-on-chip applications. We propose an integrated photonic platform that monolithically integrates on-chip light excitation and ultrasensitive detection of photoacoustic signals. We present PAS response to oxygenated and deoxygenated blood using a microfluidic chip within an integrated photonic circuit system.

I present our latest progress on multi-parametric photoacoustic microscopy (PAM) for structural, functional and metabolic imaging in vivo. Integrating hardware and software innovations, multi-parametric PAM enables comprehensive characterization of microvascular structure (diameter, tortuosity and density), mechanical property (resistance, wall shear stress, reactivity and permeability), hemodynamics (blood perfusion, oxygenation and flow), and the related tissue oxygen extraction and metabolism. This enabling technique has found broad applications in neuroscience, cardiovascular, regenerative medicine, and cancer research.

We demonstrate optical biopsy of vocal folds to assess its surface and subsurface movement during phonation on ex-vivo calf larynx using parallel OCT (POCT). In this technique, we will enable simultaneous interrogation of multiple locations along the vocal fold, there by eliminating motion-blur artifacts exhibited by the sequential sampling provided by conventional flying-spot OCT. Currently, in voice clinics, laryngologists and speech-language pathologists rely heavily on Video Stroboscopy (VS) coupling with, visual judgments of vocal fold morphology and auditory perceptions of voice quality, to make effective diagnostic, surgical and therapeutic decisions. There is a constant need of an endoscopic imaging tool in voice clinics that can directly capture the three-dimensional (3D) surface motion of the vocal folds in real time as patients phonate. To address the need, we will present a POCT/VS imager that will combine parallel swept source OCT technique with VS to provide a real time display of the vocal folds in all three axial dimensions during phonation. The results will yield cross sections (B-Scans) with ~16 co-linear sampling locations spread over ~5mm on a phonating ex-vivo calf larynx showing fluid periodic cyclic motion of the vocal folds (~A-scan rate) in real time enabled by POCT approach. We will also capture VS images in sync with POCT B-scans validating the real time cross sectional probing of POCT/VS imager.

In this paper, we summarize our recent advances in the development and pre-clinical testing of the 2-nd generation OCT-based probe for core needle biopsy guidance. The acquired OCT images are processed in real-time in a GPU unit to provide the interventional radiologist with the capability to examine the tissue cellularity at the tip of the biopsy needle before deciding to take a biopsy core. The extensive testing of this technology on a rabbit model of soft tissue cancer is discussed in detail. The pre-clinical results demonstrate the capability of this OCT-based probe for determining the in situ cellularity of the tissue at the tip of the biopsy needle and thus its potential use for improving the quality of the sampled biopsy cores.

We report the development and implementation of an epi-detected hyperspectral stimulated Raman scattering (SRS) imaging technique for label-free biomolecular subtyping of glioblastomas (GBMs). The spectral focusing hyperspectral SRS imaging technique developed generates SRS image stacks from 2800 to 3020 cm-1 at 7 cm-1 intervals within 30 s. SRS images at representative Raman shifts (e.g., 2845, 2885 and 2935 cm-1) delineate the biochemical variations and morphological differences between proneural and mesenchymal subtypes of GBMs. Multivariate curve resolution analysis on hyperspectral SRS images enables the quantification of major biomolecule distributions in mesenchymal and proneural GBMs. Further principal component analysis and linear discriminant analysis together with leave-one SRS spectrum-out, cross-validation yields a diagnostic sensitivity of 96.7% and specificity of 88.9% for differentiation between mesenchymal and proneural subtypes of GBMs. This study shows great potential of applying epi-detected hyperspectral SRS imaging technique for rapid, label-free molecular subtyping of GBMs in neurosurgery.

Deep-ultraviolet excitation fluorescence allows rapid histological imaging of a tissue. We studied deep-ultraviolet excitation fluorescence for detecting sentinel lymph node metastasis of human gastric cancer. The lymph nodes were stained with DAPI and eosin within 5 minutes. Pathologists successfully identified the metastatic lesions on deep-ultraviolet excitation fluorescence images of the lymph nodes. We also developed a new staining protocol for providing better visibility of structures in lymph nodes. Machine learning approach detected cancer metastasis in stained lymph nodes. Deep-ultraviolet excitation fluorescence is a promising tool for rapid intraoperative diagnosis of lymph node metastasis.

Light-sheet microscopy is a tool for high-throughput, volumetric tissue imaging but images and volumes from such a microscope cannot be easily interpreted by pathologists. In this work, we present a deep learning approach based on unsupervised adversarial image-to-image translation to transfer fluorescence light sheet images to pseudo-H&E images. We demonstrate that we can reconstruct pseudo-H&E images with a cumulative structural similarity index of 0.924 and a normalized RMS error of 0.871 calculated between pseudo-H&E images and corresponding registered views of H&E. We also show that there was a 97.3% accuracy between nuclei detected by pseudo-H&E and corresponding H&E images.

Blood is considered as one of the potential biofluid for better understanding of metabolic alterations under normal and diseased conditions. Among various biomolecules present in blood, Pteridine and its derivatives are considered to be important cofactors in the cellular and energy metabolism. Hence, the present study aims to characterize pteridine and its derivatives present in the blood samples collected from normal subjects, oral premalignant and malignant patients by fluorescence emission and Raman spectroscopy combined with multivariate statistical analysis. The preliminary study shows promising results and the same will be extended further and the results will be discussed in detail.

Raman spectroscopy has been widely used in the diagnosis of cancer. However, limited studies are available on differentiating the grades of dysplasia. Also, urine samples are considered for non invasive diagnosis of cancer. In this regard, the present study is aimed to characterize the tissue and urine samples collected from the same persons and analysed by Raman spectroscopy at 785nm excitation. Comparative analyses of the variation of different bio molecules present in tissue and urine samples were carried out to find the efficiency of both in early and non invasive disease diagnosis and the same will be discussed in detail.

Multiphoton microscopy (MPM) has been used to image formalin-fixed-paraffin-embedded kidney tissue sections to distinguish chromophobe renal cell carcinoma (chRCC) and oncocytoma kidney tumors. Each image has four color channels designed to acquire second harmonic generation and two-photon-excited tissue intrinsic emission signals. Due to the complexity of the images, it is difficult to capture characteristic structural and spectral features in the images for classification with robustness. In this study, we utilize a convolutional neural network (CNN) to analyze 124 MPM images and show that the CNN performs well on 5-fold validation with an average sensitivity 0.95, specificity 0.85, and accuracy 0.91.

Native fluorescence spectra of fresh normal and cancerous human breast tissues are measured to generate the excitation and emission matrix (EEM) for cancer diagnosis. Unsupervised machine learning algorithms such as principal component analysis (PCA) and non-negative matrix factorization (NMF) are used to analyze the spectral data. The relative concentrations of native fluorophores such as collagen, elastin, nicotinamide adenine dinucleotide (NADH), and flavin adenine dinucleotide (FAD) in tissues are estimated by the NMF-retrieved weights corresponding to the retrieved spectral components. The concentrations of the fluorophores and the redox ratio are used to distinguish normal and cancerous tissues using support vector machine.

Stokes shift spectroscopy, provides a simpler way of identifying the fingerprints of multiple fluorophores present in complex systems in a single scan. Blood is considered as an important biological fluid, as it has many metabolic end products of cells/tissues. In this regard, an attempt was made to characterize the blood plasma collected from normal, oral pre cancer and cancer subjects with different ∆λ values. Deconvolution method was employed for extracting the hidden spectral signatures of various fluorophores. The result of the spectral signatures of different metabolites, its variation with different ∆λ and the diagnostic potential of the ∆λ based on the statistical analysis will be discussed in detail.

The focus of the research is on a non-invasive optical method to determine collagen and water content in the skin. A major barrier to the effective use of skin therapies is the quantification of existing collagen content and hydration. Absorption of near infrared light by skin depends both on the concentration of collagen and the amount of water in the skin. We use the spectral differences between collagen and water between 1000 nm to 2000 nm (IR window 3) to determine collagen concentration in a variety of tissues by absorption, Raman spectroscopy and native fluorescence. The goal is to generate data that can be used for qualitative imaging to allow for improvement in assessing the effectiveness of skin-treatment therapies for the health care industry.

Absorption and fluorescence imaging could reduce complications in endoscopic surgeries, such as accidental resection of hidden vessels in the intestinal submucosa. Native fluorescence of the intestinal submucosa extends to 886 nm, reducing the utility of fluorescent dyes such as Indocyanine green (ICG) for angiography in infrared window I (700 nm to 900 nm), and requiring the use of absorption imaging or 2 photon excitation fluorescence (2PEF) and/or second harmonic generation (SHG). We investigate the spectral properties and 2PEF response of the submucosa for imaging in the SWIR (windows II, and III 1000 nm 2200 nm) and SHG for collagen.

The focus of the presentation is on changes detected in the fluorescence from endogenous fluorophores for classification of human brain gliomas. 237 fluorescence spectra were collected from 61 subjects with four grades of ex-vivo glioma tumors. The four grades of glioma tumors were identified based on the characteristic native molecular fluorophores using the ratios of the peak intensities and peak positions in the fluorescence spectra. The fluorescence peaks of the major-contribution biomarkers were found to play important roles in the cellular energy metabolism and the pathway of glycolysis and metabolic activity.

Second harmonic generation (SHG) imaging and resonance Raman spectroscopy (RRS) offer rapid, label-free detection of molecular and morphological features that can characterize biological tissues at subcellular resolution. In this study, we employed in vivo SHG imaging and ex vivo RRS to discriminate metastatic triple-negative breast cancer (TNBC) with non-metastatic tumors in mice. Our study is the first to propose SHG and RRS as a promising novel method, and demonstrates the potential of using optical imaging techniques for early detection of TNBC.

Abnormal tryptophan metabolism is a major factor in Alzheimer’s. Thus, understanding indoleamine 2,3-dioxygenase (IDO), an enzyme that causes increased tryptophan metabolism down the kynurenine pathway, is crucial. The hippocampus, Brodmann’s area 9 (BA9) and Brodmann’s area 17 (BA17) from five Alzheimer’s patients, one patient with psychosis and three age-matched, normal controls (27 samples) were studied. An update on optical properties of Alzheimer’s tissues, utilizing tryptophan/kynurenines ratios, is reported. Ratios of tryptophan/kynurenine were decreased in the hippocampus and BA9 in patients with Alzheimer’s, consistent with increased neuroinflammation and IDO activity in these areas. Increases in kynurenines were not seen in BA17.

Microscopy with Ultraviolet Surface Excitation (MUSE) is a rapid, simple, and inexpensive imaging technique that can be integrated into a life science classroom to enhance education and complement the high school life science curriculum. MUSE utilizes a low-power ultraviolet LED at wavelengths around 270 nm to propagate light about 10um into a tissue, thereby illuminating only the top cell layer, which allows for imaging of the cellular organization without thinly sectioned slides. Laboratory exercises have been developed that allow students to individually complete each step of the procedure in order to engage students while reinforcing their knowledge of plant and animal microanatomy.

The research focuses on understanding the effects of mixed solute and solvents using Raman and Resonance Raman scattering on the inclusion of very low concentrations of a biomolecule, such as beta-carotene, into a solvent observed increased intensity of the Raman signal as opposed to the solvent and mixed solvents alone. The excitation of CH3 modes to daughter modes and other mixed molecules show the effect of anharmonic three and four body collisions and vibrational energy transfer. The Raman intensity can rise in the presence of a second solvent using various combinations of the solvents acetone, carbon disulfide, carbon tetrachloride and methanol.

Mueller Polarimetric Imaging (MPI) has shown very promising results in biomedical applications, especially for detection of precancerous tissues. Extending these results to in vivo characterization remains an instrumental challenge. We show an innovative and pragmatic approach for building full-field MPI systems based on Ferroelectric Liquid Crystals capable of fast multispectral (in the visible range) analysis of biological tissues in vivo, with high accuracy, while using compact components. We constructed a first simultaneous multispectral MPI colposcope for the analysis of the uterine cervix in vivo, as well as a first multispectral MPI laparoscope for use in minimally invasive surgery.

We investigate the applicability of using cylindrical vector beam (CVB) and Laguerre-Gaussian (LG) beams for optical biopsy. In current presentation propagation of CVB and LG beams in anisotropic turbid tissue-like scattering media is considered in comparison to conventional Gaussian beams. We demonstrate that by applying CVB and LG beams the sensitivity of the conventional polarimetry-based approach is increased at least twice in comparison with the experiments utilizing ‘simple’ Gaussian polarized light. The results of the study suggest that there is a high potential in application of vector light beams in tissue diagnosis.

Muscular dystrophy (MD) has been reported to change the stiffness of the affected muscle. In the present report we expand upon a previous ex vivo study and show that the measurements of stiffness can be obtained non-invasively in a living specimen using Brillouin elastography. We have obtained the Brillouin shift measurements of GFP-tagged and untagged control and MD mutant Drosophila larvae, in vivo. The results indicate that the increase in the muscle’s Brillouin shift between control and MD mutant larvae groups is statistically significant (p<0.05).The reported work showcases the applicability of Brillouin elastography for non-invasive observations of muscular degeneration progression.

Biological tissues characterization can be approached by optical techniques, such as Optical Coherence Tomography, spectroscopy or fluorescence. Diffuse Reflectance Spectroscopy (DRS) provides intrinsic molecular contrast in reflection. In this work several types of ex-vivo porcine tissues are extracted and measured by DRS. Spectral measurements are made on different specimens, and on different points of each sample. Spectra are normalized and several algorithms for dimension and variability reduction are applied. Several biomarkers are proposed for tissue classification, and different classifiers are applied. The results could be of interest in image-guided surgery or other types of optical biopsy applications

The spectral and spatial resolution of hyperspectral imaging is useful for investigation of tissue autofluorescence. The low-light, noisy conditions of the technique usually necessitates noise removal for extraction of precise spectral signatures and peak shifts. However, noise removal techniques like low-pass filtering or the Maximum Noise Fraction transform might discard information or distort spectral features. Smoothing splines is proposed as an alternative technique. Continuous tuning parameters and use of natural cubic splines makes the method advantageous for unbiased peak extraction. The method was used to estimate autofluorescence peak shifts, and found to perform well in comparison with the other techniques.

We developed a ROI based segmented cell data analysis approach for the fluorescence lifetime images collected using Becker-Hickl FLIM hardware integrated to a Zeiss 780 multiphoton system. The advantage of ROI based segmented data analysis method allows us to discriminate the heterogeneous distribution of mitochondrial OXPHOS from cytosolic glycolysis in living prostate cancer cells. We expanded the common FLIM assay parameters by introducing a novel Fluorescence Lifetime Redox Ratio (FLIRR) measurement. The new assay is flexible and can be applied to very specific FLIM auto-fluorescent targets, but is equally suitable for other FLIM modalities.

Restoring normal functioning and tissue healing after surgical intervention is, among others, critically dependent on tissue oxygenation and perfusion. Tissue necrosis, caused by inadequate tissue perfusion and/or oxygenation, is a common complication after surgical reconstruction of e.g. bowel anastomoses or skin defects. An emerging technique is hyperspectral imaging, which is capable to detect physiological parameters, such as the oxygenation. In this proof-of-concept study the capability of non-invasively detecting the cutaneous skin oxygenation and perfusion as assessed by a snapshot hyperspectral camera and Laser Speckle Contrast Imaging is explored in human volunteers.

A recently developed CMOS SPAD line sensor is used to separate Raman scattering from background fluorescence without the use of time-gating, relying entirely on the in-pixel time-correlated single photon counting (TCSPC). The system delivers both Raman and time-resolved fluorescence decay data and is being developed with the aim of evaluating the suitability of liver tissue for transplant surgery as their high fluorescence emission across a wide spectral range poses particular challenges to commercial Raman systems. The system is benchmarked using samples of pure distilled-water and common organic fluorophores, in comparison with results from a Renishaw InVia spectrometer.

We are introducing an application of a machine learning approach for express analysis of Laser Speckle (LS) images. This application can be utilized for real-time visualization of vascular beds in vivo. This research used Waikato Environment for Knowledge Analysis (Weka) integrated with Fiji/ImageJ software. A large number of acquired LS images are averaged, then used as references for training Weka classifiers. Subsequently, a bundle of these Weka classifiers are produced. We defined the minimal number of raw LS images based on a phenomenological model to minimize the time needed for LS data analysis. Finally, a new perceptually uniform color coding approach is developed for highlighting targeted blood vessels. The developed LS processing approach is especially convenient, because of its high potential for blood vessel visualization during real-time intraoperative vascular imaging in vivo.

Most recently, the second (1100-1350 nm), third (1600-1870) and fourth (2100-2350 nm) NIR windows have received increased attention for use in linear and nonlinear imaging and spectroscopy. Due to minimal scattering at these windows, there is a reduction in blurring and image quality is enhanced. SWIR wavelengths can penetrate deeper than when using conventional methods and are being utilized for medical applications including brain imaging, identifying bone micro-fractures and delineating breast cancer margins. The supercontinuum laser provides a powerful broadband source that can be used to increase SWIR applications and continue to provide medical benefits. Recent advances will be discussed.

Modern battlefield injuries exhibit large soft tissue loss from blasts and projectiles. Current wound assessments are based upon visual observation, with diagnostics of improper healing being subjective. Technologies that utilise concepts of optical imaging and spectroscopy can be used to allow spatial identification of biomarkers which act as pre-cursers to improper healing. To demonstrate the applicability of this technique, wound biopsies from traumatic injuries were assessed. This work highlights the utility and benefits of spatially and spectrally derived maps for wound assessment in the mid-IR wavelength region.

Surface-enhanced infrared absorption (SEIRA) based on top-down fabricated substrates such as nanoantennas, nanoslits, and metasurfaces has been demonstrated as a versatile technique that can characterize adsorbed protein and lipid films. Here, we demonstrate the use of metasurface-enhanced infrared reflection spectroscopy (MEIRS) to observe live cells cultured on top of the plasmonic metasurface. We will demonstrate that it is possible to differentiate between normal and cancerous cells through their spectroscopic fingerprints. Furthermore, we will show the effect of different anticancer cocktails (doxorubicin, salinomycin, and their combination) on cancer cells, as observed by MEIRS.

Noninvasive deep brain stimulation is an important goal in neuroscience and neuroengineering. Optogenetics normally requires the use of a laser fiber inserted into the brain. We used specialized nanoparticles, named upconversion nanoparticles (UCNPs), that can upconvert near-infrared light from outside the brain into the local emission of blue-green light to optogenetically stimulate deep brain neurons. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations through activation of inhibitory neurons in the medial septum, silenced seizure by inhibition of hippocampal excitatory cells, and triggered memory recall. UCNP technology will enable less-invasive optical neuronal activity manipulation with the potential for remote therapy.

We present a mid-infrared spectral-domain optical coherence tomography system operating at 4 μm central wavelength with a very high axial resolution of 8.6 μm enabled by more than 1 μm bandwidth from 3.58-4.63 μm produced by a mid-infrared supercontinuum laser. The system produces 2D cross-sectional images in real-time enabled the high-brightness of the supercontinuum source in combination with broadband upconversion of the signal to 820-865 nm, where a standard 800 nm array spectrometer can be used for fast detection. Images produced by the mid-infrared system are compared with those delivered by a state-of-the-art ultra-high-resolution near-infrared optical coherence tomography system operating at 1.3 μm, which is normally used in dermatology for identifying skin disease including skin cancer. We discuss the potential applications for this technology for imaging in highly scattering samples, as well as current limitations and challenges.

Hyperspectral imaging is an imaging modality allowing high spectral and spatial resolution. It has previously been shown that short wavelength infrared (SWIR) hyperspectral imaging can be a supplement to spectroscopy and imaging in the visible wavelength range. In this paper a collection of hyperspectral data in the SWIR spectral range (950-2500nm) from from tissue samples, in vivo and ex vivo human- and porcine skin is shown. Furthermore, it is discussed how hyperspectral information can be processed and utilized in optical tissue characterization and optical diagnostics. The presented results confirm that SWIR-hyperspectral is a useful tool for tissue characterization.

There is an urgent need to develop reliable and accurate methods of detection and identification of low concentrations of circulating tumor cells (CTCs). The main challenges are their low abundance and heterogeneity. Dielectrophoresis can attract CTCs to and repel the leucocytes from an AC electrode. At the same time, metasurface enhanced infrared spectroscopy can be used for phenotyping the captured CTCs. We demonstrate that a combined electrode/metasurface can be integrated with a microfluidic chamber in order to selectively capture the CTCs from a flowing mixture with over-abundant leucocytes. The captured CTCs are simultaneously subjected to spectroscopic cytopathology, all within minutes.

Widefield near-infrared (NIR) diffuse optical imaging can provide molecular and microstructural contrasts without the use of exogenous agents. Our group is developing methods to increase the molecular contrast of widefield diffuse imaging by extending the measurement spectral bandwidth to the Short Wave Infrared (SWIR): 900 – 1300 nm. The SWIR wavelength band provides improved molecular sensitivity to distinct lipid species, water, and collagen, and improved optical depth of penetration compared to the NIR, due to reduced scattering. By illuminating the tissue surface with spatially modulated light, absolute chromophore concentrations can be extracted through the technique known as Spatial Frequency Domain Imaging (SFDI). We will present data showing that SWIR SFDI can be used to monitor inflammation-induced edema, provide spatial mapping of water/lipid heterogeneity in tumors, discriminate brown from white fat in vivo, and non-invasively monitor lipids in human subjects after a high-fat meal. For example, we identified brown adipose tissue through intact skin in mice with an 88% accuracy, demonstrating the potential for applications in obesity and thermoregulation. Additionally, we conducted a study in human normal volunteers that demonstrated the ability to non-invasively track blood lipid content in vascular and avascular tissue compartments. We found a strong correlation between our non-invasive measurements and blood draws (rho=0.67). We will also show how time-multiplexed SFDI can provide faster and more robust hyperspectral data sets, increasing throughput for preclinical testing and reducing barriers to clinical implementation.

The development of new, compact mid-infrared light sources is critical to enable biomedical sensing applications in resource-limited environments. In this talk, we will review progress in fiber-based mid-IR sources, which are ideally suited for clinical environments due to their compact size and waveguide format. Progress with supercontinuum sources will be discussed, in addition to our recent results developing new swept-wavelength mid-IR fiber lasers using the promising dysprosium ion to achieve broadly tunable sources which are orders of magnitude brighter than typical supercontinua. Ammonia detection results using this source will be presented and further sensing applications are ongoing.

Progress in biomedical mid-infrared hyperspectral imaging with fiber-based supercontinuum laser light. Angela B Seddon Mid-Infrared Photonics Group, George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, NG7 2RD, UK. A new paradigm in mid-infrared (MIR) biophotonics is opening up. The idea is of portable, MIR hyperspectral imaging in real-time for healthcare, including for in vivo cancer screening and diagnosis, based on new MIR fiber-optics. At the heart of the MIR fiber-optic approach are fiber-based MIR-supercontinuum (SC) broadband laser sources. First time reports of tissue hyperspectral imaging using fiber-based MIR-SC laser sources are reviewed here.