The quantitative measurement of structural alterations at the nanoscale level is important for understanding the physical states of weakly disordered optical mediums such as cells/tissues. Progress in certain diseases, such as cancer or abnormalities in the brain, is associated with the nanoscale structural alterations at basic building blocks of the cells/tissues. Elastic light scattering, especially at visible wavelengths range provides non-invasive ways to probe the cells/tissues up to nanoscale level. Therefore, a mesoscopic physics-based open light scattering technique with added finer focusing, partial wave spectroscopy (PWS), is developed to probe nanoscale changes. Then, molecular-specific light localization technique, a close scattering approach called inverse participation ratio (IPR) is proposed that is sensitive to nano to microstructural cell/tissue alterations. In this dissertation, we have introduced the further engineered PWS system with the finer focus for precise volume scattering and molecular-specific light localization IPR techniques. As an application of PWS, we first probe precise scattering volume in commercially available tissue microarrays (TMA) tissue samples to standardize the existing cancer diagnostic methods by distinguishing the cancer stages. We also apply the PWS technique to probe chemotherapy drug-treated metastasizing cancer patients by xenografting prostate cancer cells using a mouse model and identify drug-sensitive and drug-resistance treatment cases. On the other hand, as an illustration of another mesoscopic physics-based molecular specific light localization technique, Confocal-IPR, we study the effects of a probiotic on chronic alcoholic mice brains by targeting the molecular specific alteration in glial cells, astrocytes and microglia, and chromatin of the brain cells through staining with appropriate dyes/proteins. Using structural disorder of IPR as a biomarker, the results show that probiotics in the presence of alcohol are beneficial and help overall brain health. Finally, a TEM-IPR study was performed using nanoscale resolution TEM imaging to support the optical IPR method by studying the anti-cancerous drug effect in ovarian cancer cells. The result shows that we can quantitatively measure the effect of anti-cancerous drugs in cancer treatment and the level of tumorigenicity far below the diffraction limit, and it has a similar effect and supports the optical IPR method.

L’acoustique picoseconde est une technique qui permet de générer et de détecter des ondes acoustiques de longueur d’onde submicrométrique par l’utilisation d’impulsions lumineuses ultrarapides (100 fs). Si la technique commence à être appliquée industriellement pour le contrôle non-destructif de films solides micrométriques, comme les microprocesseurs, très peu d’études concernent son application aux milieux liquides ou mous, malgré son potentiel unique pour les mesures acoustiques très hautes fréquences (supérieur à la dizaine de GHz). Ce travail de thèse dresse un premier panorama d’applications possibles de la technique d’acoustique picoseconde pour l’étude d’une cellule biologique unique, dont l’épaisseur peut être d’une centaine de nanomètres à quelques micromètres. Les résolutions atteintes permettent des applications pour l’imagerie et la tomographie acoustique d’une cellule unique par la détermination locale de ses propriétés physiques. Un modèle de simulation analytique est développé pour aider à la compréhension des signaux détectés et pour la résolution du problème inverse. La génération acoustique est simulée en résolvant les équations couplées de diffusion de la chaleur et de la propagation acoustique. La détection optique est ensuite étudiée en résolvant l’équation de Maxwell où les phénomènes thermiques et acoustiques perturbent l’indice optique du matériau. Pour les besoins expérimentaux, une enceinte biologique, étanche et thermostatée, est conçue. De même, le montage laser est adapté pour permettre une détection bicolore de l’onde acoustique se propageant dans la cellule. Enfin, un microscope combinant la visualisation des cellules par épifluorescence au dispositif laser expérimental est développé. Ce dernier permet de localiser précisément les éléments subcellulaires de la cellule, pour ensuite les étudier par acoustique picoseconde. La démonstration du potentiel de la méthode pour l’imagerie cellulaire et l’évaluation de sa sensibilité est faite sur cellule végétale. Ensuite, une mesure quantitative des propriétés viscoélastiques de cellules ostéoblastes (MC3T3-E1), adhérentes sur un matériau mimant une prothèse de titane, est réalisée. Puis, l’effet du peptide RGD et de la protéine BMP-2 sur les propriétés viscoélastiques de la cellule ostéoblaste est quantifié. Ce travail est réalisé en partenariat avec une équipe de recherche en bio-ingénierie et reconstruction tissulaire, l’U577. / The picosecond ultrasonics technique is well suited to generate and to probe acoustic waves of submicromic wavelength using ultrafast light pulses (100 fs). If the technique starts to be used for non-destructive testing in industry, for micrometric solid films (microprocessor) for example, very few applications concern liquids or soft media, despite its unique potential for acoustic measurements at very high acoustic frequencies (up to ten GHz). This PhD study gives a first comprehensive overview of the applications of the picosecond ultrasonics technique for the study of a single biological cell, the thickness of which can be from around 100 nm to a few µm. Measurement accuracy is high enough for imaging a single cell and for evaluating its local physical properties. To understand the detected data, an analytical model is developed. This model is used too for the inverse model resolution. The acoustic generation is simulated solving the coupled equations of heat diffusion and of acoustic wave propagation. Optical detection is then studied solving the Maxwell equations where both thermal and acoustic phenomena perturb optical index of the media. For experiments, a biocompatible sample holder, leakproof and thermocontrolled, is built. In the same way, the optical experimental setup is adapted to allow a two color probing of the ultrafast photo-acoustic response in a single cell. Finally, a microscope combining cell fluorescence visualisation and the picosecond ultrasonic laser setup is developed. It allows to localize precisely the cell sub-components and to probe them by the picosecond ultrasonics technique. The demonstration of the technique for the single cell imaging and the evaluation of its accuracy is performed on vegetal cells. Then, a quantitative measurement of the viscoelastic properties of single osteoblast cells (MC3T3-E1), adhering on a bone substitute material (Ti6Al4V), is performed. RGD peptide and BMP-2 proteins effects on the cell osteoblast viscoelastic properties are quantified. This work is performed with a tissue or bone substitute engineering research team.

Opioid overdose is a growing epidemic plaguing the United States. Overdose related death has risen from 16,849 in 1999 to 69,029 in 2018. Almost 7 out of 10 of these deaths were due to opioids with 47% being caused by fentanyl or other synthetic opioids. There is a strong need to reduce the amount of overdose-related deaths. Indirect methods should be a first priority, and include counseling and care. For some individuals, this treatment option is unavailable because the drug user may not have the desire or economic means to pursue it. In this case, a more direct preventative approach is needed. This paper presents a novel method of detecting poor peripheral oxygenation, a biomarker linked to opioid overdose. A wristwatch near-infrared spectroscopy device (NIRS) was developed. SPICE simulations were conducted to confirm proper operation of electrical systems. The device was fabricated on a printed circuit board and mounted to a 3D printed enclosure. Absorbance of green, red and infrared (IR) light were measured. Additionally, peripheral capillary oxygen saturation (SpO2) modulation index and changes in concentration of oxyhemoglobin and deoxyhemoglobin were calculated from raw data. A brachial occlusion test was performed to mimic the effects of opioid overdose on peripheral oxygenation. A statistically significant difference (p < 0.05) was observed between pre-occlusion and during-occlusion groups in two subjects for measurement of peak-to-peak values of green raw data, red raw data, IR raw data, oxyhemoglobin concentration change, and deoxyhemoglobin concentration change. Peak-to-peak was observed as a consistent indicator of poor peripheral oxygenation and could serve as a useful metric in the detection of opioid overdose.