This PDF file contains the front matter associated with SPIE Proceedings Volume 11959 including the Title Page, Copyright information, and Table of Contents.

Fertilization is a critical reproductive step combining two gametes from parents, the egg and the sperm, to convey the genetic information to the next generation. This process is regulated in vivo by multiple factors influencing a selection of one sperm out of millions. However, due to the lack of suitable visualization approaches for in vivo fertilization processes, most of the current knowledge is derived from in vitro experiments, which cannot model the complexity of physiological states. The overall goal of this project is to capture the fertilization in vivo in a mouse model and to characterize the mechanisms regulating the dynamics of this process. Toward this goal, we recently established functional optical coherence tomography (OCT) integrated with intravital microscopy for live dynamic imaging of reproductive processes within the mouse fallopian tube. This method allowed for prolonged volumetric tracking of oocytes and embryos as well as individual spermatozoa at the site of fertilization based on their trajectories. However, visualizing the fertilization event remains a major challenge because the oocytes prior to fertilization are surrounded by a dense cloud of cumulus cells, forming the cumulus-oocyte-complex (COC), making direct sperm tracking through the optically dense cumulus matrix not feasible. This study presents the development of the speckle variance (SV) OCT analysis for volumetric tracking of sperm migration through the cumulus matrix toward the oocyte in vitro. Potentially, this method will be integrated with intravital OCT imaging to capture the process of mammalian fertilization in vivo.

Here we introduce an image fusion method based on color spaces to combine different Mueller matrix derived parameters to provide multi-dimensional structural information pixel by pixel in a single polarization staining image. Then, in order to quantitatively analyze the texture characteristics of the polarization staining images for different structures, the Tamura image processing and the gray level co-occurrence matrix (GLCM) methods are adopted to provide various evaluation indices after the images segmentations. The experimental results confirm that the information provided by the polarization staining images based on different Mueller matrix derived parameters can be used for accurate tissue structures discrimination.

Photosensitizer uptake and elimination are studied in the animal model D. melanogaster with the purpose of developing tools for highly regulated photodynamic therapy (PDT) as a model of accelerated aging and neurodegenerative disorders. The photosensitizer (PS) methylene blue (MB) is given in a concentration of 1 mM by mixing with growth media for fly consumption. Internal MB increases for eight hours following exposure to MB media. At this time, the mean trends of these early results show adequate uptake rate and maximum internal MB for PDT utility in the D. melanogaster model and potential for further applications in disease modelling.

Movement artefacts distort handheld measurements of laser speckle contrast imaging (LSCI). Enabling a robust LSCI in handheld use brings convenience for both patients and clinical staff. However, there is a lack of a comprehensive model that can predict and potentially compensate the amount of movement artefacts occurring during a handheld LSCI measurement. Here, we propose an analytical-numerical model based on the optical Doppler effect for handheld LSCI in case of translation on a high scattering static surface. The model incorporates the type of illumination as well as the imaging geometry by taking into account the spread of wavevectors for illumination and detection. We validate the theoretical model by simulated dynamic speckles and experiments for the cases of (1) planar and spherical waves illumination and (2) scrambled waves illumination. Results of the speckle simulation are in agreement with predictions of the numerical model for semi-circular form of the density functions of the incoming and outgoing wavevectors.

Tissue dynamics spectroscopy (TDS) uses coherence-gated dynamic light scattering from living tissues to predict tissue response to applied drugs. In clinical trials aimed at measuring patient chemoresistance, intra-sample variability poses a challenge for the prediction of patient response to therapy. Previous work has identified and characterized different baseline conditions and drug responses by averaging TDS signatures over patient biopsies, but most samples display more than one phenotypic response to the treatment. To address this problem, we introduce well-by-well phenotypic classification to improve chemoresistance accuracy. The methodology is applied here to a recently concluded clinical trial measuring TDS of human esophageal cancer.

Recent advances in optical imaging and spectroscopy of biological tissues facilitated groundbreaking discoveries in physiology of the lymphatic system of mammals. One important aspect is the dynamics of the lymphatic drainage between the eyes and the brain, which was potentially linked to a number of diseases. A mouse is a versatile model providing convenient in-vivo and ex-vivo studies of lymphatic drainage by multispectral optoacoustic tomography (MSOT) using near-infrared exogenous tracers. The accuracy of the in-vivo spectral umixing of chromohores by MSOT still requires further improvement to achieve required resolution. To achieve this goal, we studied factors such as the spectrum of wavelengths and skin pigmentation affecting the quantitative accuracy of MSOT tracking of the novel hybrid photoacoustic-fluorescent contrast agent QC-1/BSA/BODIPY injected into the lymph of C57 pigmented mice. We also compared performances of various spectral algorithms.

The present work demonstrates the assessment of cytotoxicity upconversion nanoparticles (UCNPs) coated by SiO₂ on different normal and cancer murine cell lines in vitro. The cell viability is scored for cytotoxic effects of UCNPs at dark conditions. UCNPs coated by silica shells provide a dose-dependent cytotoxic effect on all studied cell lines which was most pronounced for the Raw264.7 cell line. It is probably caused by the high phagocytic activity of macrophages. The less sensitive cell line was 4T1. The statistically significant differences in cell viability after 24 and 48 h of incubation of cells with particles were observed just for the macrophage cell line. It is worth notifying that after 48 h of incubation the cytotoxic effect on Raw 264.7 cell line increased which shows a possible negative effect on some subpopulations on blood cells. The obtained results confirm a high sensitivity of the UCNPs to the concentration variations within cells. Carriers based on UCNPs and dyes are promising alternatives to photosensitizer for traditional photodynamic therapy and possess prominent potentials in biological and clinical applications.