Advanced optical microscopy toolkits for non-invasive imaging in oncology

Abstract

Despite significant advances in the fields of biophotonics and oncology alike, several challenges persist in the study, assessment, and treatment of cancer, ranging from the accurate identification and examination of potential risk factors, early diagnosis of dysplastic lesions, and monitoring of the complex heterogeneity of cellular populations within tumors. To study such dynamics at the microscale, non-invasive optical toolkits offer the potential to identify, characterize, and visualize key molecules and their interactions in their native biological context, ranging from in vitro cell cultures to in vivo studies in both animal models and humans. In the present thesis, examples of such applications of optical tools will be presented, including: (1) the assessment of cellular oxidative stress in ex vivo human skin cultures by imaging endogenous and exogenous fluorescent compounds using two-photon excitation fluorescence (TPEF) and fluorescence lifetime imaging microscopy (FLIM); (2) visualizing water and lipid distribution as well as cellular morphology using coherent Raman scattering (CRS) imaging techniques in the stratum corneum, the most superficial layer of the epidermis; (3) using photoconvertible labels to optically tag cell sub-populations of interest in situ for long-term monitoring of heterogeneous cell cultures from in vitro monolayers to in vivo xenograft models; (4) visualizing melanin species in the context of melanoma with coherent anti-Stokes Raman scattering (CARS) and sum-frequency absorption (SFA) microscopies. Altogether, development of such advanced microscopy toolkits will serve to improve both understanding of cancer pathology, as well as to validate clinical diagnostic and therapeutic strategies.