Study On Pentamethine And Phthalocyanine Fluorescence Dyes

With the development of life science and technology, in order to meet the requirements in ever-changing biological detection technology, design and synthesis of fluorescent dyes which having good spectral properties is still the key of fluorescence detection technology. As the most important near-infrared fluorescent dyes, cyanine and phthalocyanine dyes can avoid the background interference caused by biological sample autofluorescence and self-absorption, it is often used as a fluorescent label or fluorescent probe in biological detection field in recent years. However, cyanine dyes have two drawbacks which they have poor photostability and easy to aggregate. Phthalocyanine dyes have excellent photostability, but it’s easy to aggregate and therefore quench the fluorescence by π-π stacking interactions.This paper designed and synthesised of two pentamethine cyanine dyes Cy5-NHS1 and Cy5-NHS2. Introduced bulky benzyl in N-bit of indole ring, which can effectively improve the photostability of pentamethine. The detection limit of Cy5-NHS1 and Cy5-NHS2 for BSA were 10-8 mol/L, which having a higher sensitivity. Both Cy5-NHS1 and Cy5-NHS2 have good membrane permeability and can stain the mitochondria of MCF-7 cells. This paper also synthesised of an axial substituted aluminum phthalocyanine PcAIR, when pH decreased from 7.4 to 4.0, the fluorescence intensity of PcAIR increased 57 fold. Meanwhile, PcAIR having good membrane permeability and can stain the MCF-7 cells. One of the unique features of tumours is their relatively lower pH in the extracellular region compared with that around normal tissues, makeing PcAIR a potential tumor-selective fluorescent probe.