title: A highly selective and colorimetric assay of lysine by molecular-driven gold nanorods assembly.
abstract: In this contribution, a simple, rapid, colorimeteric and selective assay for lysine was achieved by a controllable end-to-end assembly of gold nanorods (AuNRs) in the presence of Eu(3+) and lysine. This one-pot end-to-end assembly of 11-mercaptoundecanoic acid (MUA) modified AuNRs was occurred in Britton-Robinson buffer of pH 6.0, which involves the coordination binding between Eu(3+) and COO(-) groups as well as the electrostatic interaction of the COO(-) groups of MUA with the -NH(3)(+) group of lysine. As monitored by absorption spectra, scanning electron microscopic (SEM) images and dynamic light scattering (DLS) measurement, the end-to-end chain assembly results in large red-shift in the longitudinal plasmon resonance absorption (LPRA), giving red-to-blue color change of AuNRs. Importantly, it was found that the red-shift of LPRA is linearly proportional to the concentrations of lysine in the range of 5.0×10(-6)-1.0×10(-3)M with the limit of detection (LOD) being 1.6×10(-6)M (3σ/k). This red-shift of LPRA is highly selective, making it possible to develop a rapid, selective and visual assay for lysine in food samples.
authors.affiliation: Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Pu
authors.initials: P
authors.lastname: Zhang
authors.forename: Chun Mei
authors.initials: CM
authors.lastname: Li
authors.forename: Yuan Fang
authors.initials: YF
authors.lastname: Li
authors.forename: Cheng Zhi
authors.initials: CZ
authors.lastname: Huang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods; D005063:Europium / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D008239:Lysine / Q000302:isolation & purification*; D043942:Nanotubes / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: C505222:11-mercaptoundecanoic acid; D005227:Fatty Acids; D013438:Sulfhydryl Compounds; D005063:Europium; D006046:Gold; D008239:Lysine