title: Colorimetric sensor for cysteine in human urine based on novel gold nanoparticles.
abstract: Herein, a novel, high sensitive, and specific colorimetric sensor for cysteine (Cys) based on pectinase protected gold nanoparticles (P@AuNPs) has been demonstrated for the first time. The P@AuNPs were synthesized by "MW-assisted heat method" and were characterized by UV-vis, TEM, FT-IR and zeta potential techniques. Cys could cause the aggregation of P@AuNPs due to formation of the strong covalent Au-S bond and electrostatic binding. As the Cys concentration increased, the color of the solutions gradually changed from wine-red to blue as well as the large absorption band shifted from 523 to 650nm upon P@AuNPs aggregation. In addition, various experimental parameters such as pH, the amount of P@AuNPs and incubation time were investigated for the optimum sensing conditions. The concentration of Cys could be determined by monitoring with the naked eye or a UV-vis spectrometer. The proposed colorimetric sensor showed an extreme selectivity toward the determination of Cys in the presence of 20-fold all other different interferents. Under optimum conditions, this method exhibited two good linear ranges from 4.85×10-9to 3.02×10-4M (R2=0.996) and 3.25×10-3to 1.03×10-2M (R2=0.999), with a low detection limit of 4.6×10-9M. Moreover, this colorimetric sensor was successfully applied to the detection of Cys in human urine samples, demonstrating its great value for practical application in biological systems.
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China. Electronic address: yanzhang@sxu.edu.cn.
authors: Yan
authors: Y
authors: Zhang
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China.
authors: Jingjing
authors: J
authors: Jiang
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China.
authors: Min
authors: M
authors: Li
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China.
authors: Pengfei
authors: P
authors: Gao
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China.
authors: Ying
authors: Y
authors: Zhou
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China.
authors: Guomei
authors: G
authors: Zhang
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China. Electronic address: smshuang@sxu.edu.cn.
authors: Shaomin
authors: S
authors: Shuang
authors: School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, 92 Wucheng Road, Taiyuan, PR China.
authors: Chuan
authors: C
authors: Dong
mesh_terms: D003124:Colorimetry; D003545:Cysteine / Q000032:analysis / Q000737:chemistry / Q000652:urine*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D011096:Polygalacturonase / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006046:Gold; D011096:Polygalacturonase; D003545:Cysteine
keywords: Colorimetric sensor; Cysteine; Gold nanoparticles; Pectinase