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Sugar-modified porphyrin and phthalocyanine near-infrared fluorescent molecular probes

Author: HeXuJun
Tutor: LiuTianJun
School: Peking Union Medical College , China
Course: Medicinal Chemistry
Keywords: Molecular Imaging Fluorescence probe Near infrared Sugar Phthalocyanines Porphyrin
CLC: R914
Type: Master's thesis
Year: 2010
Downloads: 117
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Abstract

Molecular imaging in vivo can display the biological processes at the cellular and molecular level, reveal the mechanism of physiological and pathological processes, and provide effective methods of detecting and tracking the diseases treatments. Its applications include the early clinical disease diagnosis, qualitative and quantitative evaluation curative effect and so on. Optical imaging has many advantages, such as non-ionic low-energy radiation, high sensitivity, continuous real-time monitoring, non-invasive or minimally invasive, relatively inexpensive equipment and low price. Particularly, near-infrared fluorescence imaging has a better application prospect. As the organisms have low scattering effect and background interference in near-infrared region, this increases near-infrared image sensitivity and penetrating depth in biological tissue. So near-infrared fluorescence imaging can be used in deep tissues and organs for detection and imaging owning to its specific advantages.The core element of molecular imaging is molecular probe, but current optical molecular probes can not meet the practical need, further optimization is required to improve their properties, including light transmission in depth and the luminescence quantum efficiency, good biocompatibility and targeting ability. In this paper, fluorescent dyes with four pyrrole moieties (including porphyrins and phthalocyanines) were studied as near-infrared fluorescent probes for biological tissue imaging. Either porphyrin or phthalocyanine, their luminescence efficiency, emission wavelength as well as the singlet and triplet state characteristics could be monitored by the substituent at periphery and core elements doping, and they have good optical stability in near-infrared region. Sugar modification can not only improve the substrate solubility and biocompatibility, but also increase tumor targeting function of imaging probes. Here near-infrared fluorescent probes were designed to meet molecular probes function and improve imaging effects by combining porphyrin or phthalocyanine with sugar.Sugar and alkynyl modified porphyrin with two, three and four saccharide moieties was synthesized by condensation of intermediates trimethylsilyl propynal, sugar-modified aldehyde, sugar-modified dipyrrole respectively. Sugar decorated phthalocyanine was synthesized by condensation of its saccharide precursor, sugar modified benzene dicarbonitrile,which is achieved by reaction of saccharide azide with alkynyl modified benzene dicarbonitrile through Click reaction. Based on this approach, we synthesized glucose and lactose decorated phthalocyanines. All of compounds were characterized by mass spectrometry, nuclear magnetic resonance spectrum and so on. Their light stability and fluorescence quantum yield were evaluated by spectroscopic method. Results show they have good optical stability and high emission ability in NIR region. Deprotection in sugar results in solubility enhancement in aqueous solution. We selected modified sugar phthalocyanine as probe for animal imaging in vivo. Mice with liver cancer were used as animal model and assessed by in vivo fluorescence imaging to evaluate near-infrared imaging effect and organ aggregation and distribution of probe in vivo. The results proved that sugar modified phthalocyanine have obvious imaging effect and a certain tumor targeting ability. So the near infrared optical probe can be applied in the diagnosis of cancer in future.

Sugar-modified porphyrin and phthalocyanine near-infrared fluorescent molecular probes

Abstract

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