title: Tuning interionic interaction by rationally controlling solution pH for highly selective colorimetric sensing of arginine.
abstract: Direct selective sensing of arginine in central nervous systems remains very essential to understanding of the molecular basis of some physiological events. This study presents the first demonstration on a simple yet effective method for arginine sensing with gold nanoparticles (Au-NPs) as the signal readout. The rationale for the method is based on the pH-dependent feature of the interionic interaction between cysteine and arginine. At pH 6.0, cysteine can only interact with arginine through the ion-pair interaction and such interaction can lead to the changes in both the solution color and UV-vis spectrum of the cysteine-protected Au-NPs upon the addition of arginine. These changes are further developed into an analytical strategy for effective sensing of arginine by rationally controlling the pH values of Au-NP dispersions with the ratio of the absorbance at 650 nm (A 650) to that at 520 nm (A 520) (A 650/A 520) as a parameter for analysis. The method is responsive to arginine without the interference from other species in the cerebral system; under the optimized conditions, the A 650/A 520 values are linear with the concentration of arginine within a concentration range from 0.80 to 64 μM, yet remain unchanged with the addition of other kinds of amino acids or the species in the central nervous system into the Au-NPs dispersion containing cysteine. The method demonstrated here is reliable and robust and could thus be used for detection of the increase of arginine in central nervous systems.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing, 100190, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Qian
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing, 100190, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Hao
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing, 100190, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Ma
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing, 100190, China. yuping@iccas.ac.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Yu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing, 100190, China. lqmao@iccas.ac.cn.
authors.forename: Lanqun
authors.initials: L
authors.lastname: Mao
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D003124:Colorimetry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001120:Arginine
keywords: Arginine; Gold nanoparticles; In vivo analysis; Interionic interaction