Doctor of Philosophy, University of Akron, 2024, Chemistry

Organic sensors emitting in the near-infrared region (600-900 nm) are desirable for biological applications. Through the combination of different functional groups with Excited State Intramolecular Proton Transfer (ESIPT) segments, novel probes have been crafted to attain large Stokes shift, improved sensitivity, selectivity, and the ability to tune emission towards the NIR region. Chapter I summarizes recent progress in this field, by including the photophysical properties inherent in ESIPT dyes, and investigated the impact of structural and environmental factors to their fluorescence. Furthermore, the potential applications of these probes as imaging reagents are exemplified such as labeling intracellular membranes, mitochondria, lysosomes, and detecting biomolecules. In Chapter II, four NIR-emitting ESIPT dyes, each featuring distinct cyanine terminal groups, were scrutinized to assess their fluorescence lifetime characteristics in the polar aprotic solvent. By using time–correlated single–photon counting (TCSPC) method, these ESIPT-based dyes revealed a two-component exponential decay in about 2-4 nanoseconds (ns) which was proved to exclusively from keto tautomer. The model compounds (1.10 and 2.2) as well as low-temperature fluorescence spectroscopy (at -189 ℃) identified intramolecular charge transfer (ICT) as a prominent factor influencing the lifetime values. ESIPT simplified lifetime components. Chapter III includes ESIPT probes with benzoindolium terminal group, which shows large Stokes shift (Δλ≈250 nm) and good quantum yield. The probe also exhibited a minor absorption (~580 nm in DCM) and emission (∼ 610 nm in DCM), attributed to a zwitterionic structure formed through deprotonation of phenolic proton. Fluorescence confocal microscopy investigations highlighted the probe's excellent selectivity for mitochondria, and unusually strong emission in the 595 nm channel rather than the expected 700 nm channel. The study thus illustrated a reaction-based pro (open full item for complete abstract)

Committee: Yi Pang (Advisor); Christopher Ziegler (Committee Member); Chrys Wesdemiotis (Committee Member); Chunming Liu (Committee Member); Tianbo Liu (Committee Member) Subjects: Analytical Chemistry; Biochemistry; Chemistry; Organic Chemistry; Physical Chemistry

Doctor of Philosophy, The Ohio State University, 2009, Electrical and Computer Engineering

The convergence of emerging challenges in biological research and developments in imaging and computing technologies suggests that image analysis will play an important role in providing a better understanding of biological phenomenon. The ability of imaging to localize molecular information is a key capability in the post-genomic era and will be critical in discovering the roles of genes and the relationships that connect them. The scale of the data in these emerging challenges is daunting; high throughput microscopy can generate hundreds of gigabytes to terabytes of high-resolution imagery even for studies limited in scope to a single gene or interaction. In addition to the scale of the data, the analysis of microscopic image content presents significant problems for the state-of-the-art in image analysis. This dissertation addresses two significant problems in the analysis of large histological images: reconstruction and tissue segmentation. The proposed methods form a framework that is intended to provide researchers with tools to explore and quantitatively analyze large image datasets. The works on reconstruction address several problems in the reconstruction of tissue from sequences of serial sections using image registration. A scalable algorithm for nonrigid registration is presented that features a novel method for the matching small nondescript anatomical features using geometric reasoning. Methods for the nonrigid registration of images with different stains are presented for two application scenarios. Correlation sharpness is proposed as a new measure for image similarity, and is used to map tumor suppressor gene expression to structure in mouse mammary tissues. An extended process of geometric reasoning based on the matching of cliques of anatomical features is presented and demonstrated for the nonrigid registration of immunohistochemical stain to hemotoxylin and eosin stain for human cancer images. Finally, a method for the incorporation of structural (open full item for complete abstract)

Committee: Bradley Clymer (Advisor); Kun Huang (Advisor); Ashok Krishnamurthy (Committee Member) Subjects: Electrical Engineering