Small Molecule Organic Dyes With Unique Fluorescence Characteristics:Design, Synthesis And Biological Applications Of Nanoparticles

The development of biomedical technology is fast and has absorbed tremendous attention. Fluorescence techniques have been extensively employed to develop noninvasive methodologies. At the core of all fluorescence-based methods are fluorescent labels, for example, as signaling units in targeted probes or sensor molecules, which can be excited and detected by common commercial instruments. Important features of suitable fluorophores are with high fluorescence brightness, excellent long-term stability, negligible toxicity, and minimum nonspecific interactions with. To date, various fluorescent materials, such as fluorescent proteins, fluorescent semiconducting polymer dots, and semiconductor quantum dots(QDs)have been actively involved in diverse cellular imaging and tracing applications. However, the low photo bleaching threshold greatly limits the performance of fluorescent proteins and organic dyes in long-term imaging applications and their heavy-metal components resulting in the intrinsic toxicity as well as the low-pH-induced fluorescence-quenching phenomenon has motivated researchers to explore novel fluorescent probes with the goal of overcoming these obstacles.Another major challenge of conventional organic dye encapsulated nanoparticles is that their light emission is always weakened or annihilated in aggregates, which is known as aggregation caused quenching. Using of the time-resolved fluorescence spectroscopy can overcome many limitations. As a result, novel time-resolved PL nanosensors with great potential for multiplexing and time-gated cellular detection with enhanced selectivity and sensitivity are highly desirable to satisfy the growing interest in fluorescence lifetime imaging microscopy. Modern fluorescence imaging techniques have become essential tools to provide crucial insights in understanding complicated biological processes. Because of their unique optical properties(e.g.excellent photostability, high brightness, broad absorption, and narrow emission), various fluorescent materials have attracted great interest in fluorescence bioimaging.In summary,based on the fluorescence imaging required high sensitivity, high signal-to-noise ratio and its toxicity characteristics designed a series of organic molecules as a fluorescent dye and other purposes, the main contents are the following several aspects:First, the organic dyes(CPy) are synthesized and the optic property of the CPy is studied. Second, the CPy NPs are fabricated by matrix-encapsulation method and the embedded CPYs can be modulated into spherical dots. The obtained CPy NPs are incubated with cells for long term cell imaging. Third, small molecules organic fluorescent dyes are designed and synthesized with red light properties based on TPE molecular which is with aggregation induced luminescence properties.