Boronic acid functionalized g-C3N4 nanosheets for ultrasensitive and selective sensing of glycoprotein in the physiological environmentElectronic supplementary information (ESI) available: The fluorescence properties of B-g-CN nanosheets, including the excitation/emission spectra, the variation of fluorescence intensity as a function of pH, ionic strength and UV irradiation time; effects of incubation time on the fluorescence intensities of the mixture of B-g-CN nanosheets and IgG; TEM image of

• Main Authors: Wang, Yiting, Hai, Xin, E, Shuang, Chen, Mingli, Yang, Ting, Wang, Jianhua
• Format: Journal Article
• Language: English
• Published: 08.03.2018
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c7nr09342j

As important biomarkers, glycoprotein sensing is frequently facilitated by boronic acid binding with its cis -diols. However, boronic acid based sensors suffer from drawbacks of alkali restriction and/or sensitivity limitation. Herein, we report boronic acid decorated g-C 3 N 4 nanosheets (B-g-CN) with a Wulff-type boronic acid feature, which selectively bind glycoprotein under physiological conditions. Meanwhile, the binding causes significant enhancement of the B-g-CN nanosheet fluorescence, providing the basis for glycoprotein sensing. With IgG as a model, a detection limit (LOD) of 2.2 nM (3 σ / s , n = 11) was obtained within a linear range of 6.7-67 nM. The LOD was further improved to 52 pM subject to enrichment of the nanosheets, which well enables IgG assay in human urine samples. Moreover, it was successful in imaging endogenous and exogenous glycoproteins in living cells. Boronic acid decoration of g-C 3 N 4 via EDC/NHS coupling facilitates fluorescence switching and glycoprotein sensing at neutral medium.