Sialic Acid-Imprinted Fluorescent Core鈥揝hell Particles for Selective Labeling of Cell Surface Glycans

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• 作者：Sudhirkumar Shinde ; Zahra El-Schich ; Atena Malakpour ; Wei Wan ; Nishtman Dizeyi ; Reza Mohammadi ; Knut Rurack ; Anette Gj枚rloff Wingren ; B枚rje Sellergren
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：November 4, 2015
• 年：2015
• 卷：137
• 期：43
• 页码：13908-13912
• 全文大小：329K
• ISSN：1520-5126

文摘

The expression of cell surface glycans terminating with sialic acid (SA) residues has been found to correlate with various disease states there among cancer. We here report a novel strategy for specific fluorescence labeling of such motifs. This is based on sialic acid-imprinted core鈥搒hell nanoparticles equipped with nitrobenzoxadiazole (NBD) fluorescent reporter groups allowing environmentally sensitive fluorescence detection at convenient excitation and emission wavelengths. Imprinting was achieved exploiting a hybrid approach combining reversible boronate ester formation between p-vinylphenylboronic acid and SA, the introduction of cationic amine functionalities, and the use of an NBD-appended urea-monomer as a binary hydrogen-bond donor targeting the SA carboxylic acid and OH functionalities. The monomers were grafted from 200 nm RAFT-modified silica core particles using ethylene glycol dimethacrylate (EGDMA) as cross-linker resulting in a shell thickness of ca. 10 nm. The particles displayed strong affinity for SA in methanol/water mixtures (K = 6.6 脳 10⁵ M^鈥? in 2% water, 5.9 脳 10³ M^鈥? in 98% water, B_max 鈮?10 渭mol g^鈥?), whereas binding of the competitor glucuronic acid (GA) and other monosaccharides was considerably weaker (K (GA) = 1.8 脳 10³ M^鈥? in 98% water). In cell imaging experiments, the particles selectively stained different cell lines in correlation with the SA expression level. This was further verified by enzymatic cleavage of SA and by staining using a FITC labeled SA selective lectin.