Preparation Of Aggregation-induced-emission Active Fluorescent Probe And Its Application In Detection

Sirt1is a kind of histone deacetylase (HDACs), and its cofactor is nicotinamide adeninedinucleotide(NAD+). In the presence of the cofactor, Sirt1not only can act on a variety of nonhistone proteins and histone substrates, catalyze the removal of acetyl groups fromε-N-acetylated lysine residues, but also is involved in a variety of biological function. Studieshave shown that Sirt1overexpression in cells can increase the viability of nerve function andexpression of brain-derived neurotrophic factor neurons, thus protecting nerve cells againstforeign viruses; Meanwhile Sirt1via its role in deacetylation closely regulate many tumorsignal factors, thereby affecting the various characteristics of the tumor. When normal cellstransform to cancer cells, HDACs activity is significantly enhanced, disrupting the originalgene expression equilibrium, leading to some of the effects of cell proliferation and cell cycleregulatory molecule expression imbalance, leading to malignant cells.This study involves AIE-active principle. By employing TPE-derivatives with one SO3-and two SO3-as fluorescent chromophores, and H40-Lys(Ac) as histone substrate, wedesigned and prepared new, sensitive and selective fluorescent probe for Sirt1. AIE effect is anovel mechanism of fluorescence emission, which is contrary to the traditional ACQ. AIEmolecules exhibit only weak or no fluorescence in the good solvent or in a molecularlydispersed state; while in aggregates or the blocked state of a high viscosity, a significantfluorescence intensity enhancement occurs; and TPE is the most widely used AIE molecularstructure. Sirt1triggers the deacetylation of H40-Lys(Ac), thereby turning the electroneutralpolymer into the positively charged one and the electrostatic binding with negatively chargedTPE molecular, the TPE derivatives act as cross-linkers among the polymer chains, this inturn restricts free rotatation in the TPE molecule, leading to fluorescence enhancement. Thesynthesized probe provides a new way for sensitive and selective of detection Sirt1with thedetection limit of25ng/mL. The main contents and results of this paper are as follows:(1) H40-Lys(Ac) hyperbranched polymer and AIE-active fluorescent chromophoresTPE-2OH, TPE-OH, TPE-2SO3-and TPE-SO3-have been synthesized. H40-Lys(Ac) issynthesized by esterification reaction, TPE-2OH and TPE-OH were synthesized by McMurryReaction; and the water-soluble of TPE-2SO3-and TPE-SO3-were synthesized by ring-opening reaction.(2) The fluorescent probe can be well applied to the detection of the histonedeacetylase(HDACs). Before adding Sirt1, the system have no fluorescence, after adding toSirt1, Sirt1triggers the deacetylation of H40-Lys(Ac), thereby turning the electroneutralpolymer into the positively charged one. Consequently, complexation occurs between thepositively charged polymer and the negatively charged TPE-2SO3, thereby leading to theformation of nanoaggregates due to electrostatic interaction. Eventually, the fluorescenceenhancement as a result of AIE effect is achieved.