Syntheses And Properties Of Water-soluble Near-infrared Probes Based On The Aza-BODIPY

Near-infrared fluorescence probes have high sensitivity and wide range of dynamic response to the physiological environment in biological systems, which can be safely performed with simple instruments and facilities. NIR dyes are suitable as in vitro and in vivo biomedical diagnostic agents due to efficient penetration of light through tissue and the low auto-fluorescence of endogenous chromophores in this spectral region and avoid damaging to the cellular systems under observation. Near-infrared fluorescence probes are widely used to recognise and detect a variety of substances of biological systems in living cells under the physiological environment (such as DNA, proteins, metal ions, anions, protons, etc.).Aza-BODIPY fluorescence probes have been the subjects of intense investigation due to their excellent photochemical and photophysical properties, such as long excitation wavelength, good photostability, high extinction coefficients and so on.Two kinds of functional dyes were designed and contracted based on the aza-BODIPY core in this thesis. The thesis includes the following contents:(1) Based on photoinduced electron transfer (PeT) principle, We designed and synthesized the near-infrared pH fluorescent probe TEG-DMA-Aza-BODIPY. The effects of different solvents on the fluorescent spectra were investigated. TEG -DMA-AZA-BODIPY has displayed very good water solubility. It could be completely dissolved in 100% aqueous solution. The fluorescence was weak in the neutral environment where the amine receptor remained unprotonated. Upon protonation, the fluorescence spectrum showed a strong proton induced fluorescence enhancedment at pH 1-3 and no response to the other cations (metal ions). It may be used to detect the gastric acidity in vivo (pH 1-2). TEG-DMA-Aza-BODIPY possesses a high photostability, long excitation wavelength in near infrared region (714 nm, can avoid strong interference due to background absorbance and auto-fluorescence from endogenous chromophores in sample media) and high extinction coefficient, which displays potential application as sensitizer for photodynamic therapy.(2) Based on the principle of intramolecular charge transfer (ICT), We designed and synthesized Cu²⁺ probe DCMA-Aza-BODIPY. The effects of different solvents on the fluorescent spectra were examed. The changes of the absorption spectra of this compound caused by Cu²⁺ with high sensitivity. Metal ions other than Cu²⁺ produced no change in absorption spectra. The Uv-vis spectra of DCMA-Aza-BODIPY has a good response to Cu²⁺ in the neutral environment. The color of the probe solution changed from the blue into light purple when added trace amount Cu²⁺ can be observed by naked eye. The potassium salt of DCMA - Aza-BODIPY can be potentially applied to detect the copper(II) ion in living cells for its water solublility.