title: Self-assembled dipeptide-gold nanoparticle hybrid spheres for highly sensitive amperometric hydrogen peroxide biosensors.
abstract: Novel self-assembled dipeptide-gold nanoparticle (DP-AuNP) hybrid microspheres with a hollow structure have been prepared in aqueous solution by a simple one-step method. Diphenylalanine (FF) dipeptide was used as a precursor to form simultaneously peptide spheres and a reducing agent to reduce gold ions to gold nanoparticles in water at 60°C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that formed AuNPs were localized both inside and on the surface of the dipeptide spheres. Horseradish peroxidase (HRP) as a model enzyme was further immobilized on the dipeptide-AuNP hybrid spheres to construct a mediate H2O2 amperometric biosensor. UV-vis spectroscopy showed that the immobilized HRP retained its original structure. Cyclic voltammetry characterization demonstrated that the HRP/dipeptide-AuNP hybrid spheres modified glassy carbon electrode showed high electrocatalytic activity to H2O2. The proposed biosensor exhibited a wide linear response in the range from 5.0×10(-7) to 9.7×10(-4)M with a high sensitivity of 28.3µAmM(-1). A low detection limit of 1.0×10(-7)M was estimated at S/N=3. In addition, the biosensor possessed satisfactory reproducibility and long-term stability. These results indicated that the dipeptide-AuNP hybrid sphere is a promising matrix for application in the fabrication of electrochemical biosensors due to its excellent biocompatibility and good charge-transfer ability.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Yufei
authors.initials: Y
authors.lastname: Gong
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: chenxu@mail.buct.edu.cn.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Yanluo
authors.initials: Y
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: chenxu@mail.buct.edu.cn.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Yang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004151:Dipeptides / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000032:analysis*; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D015203:Reproducibility of Results
chemical_list: D004151:Dipeptides; D004800:Enzymes, Immobilized; D006046:Gold; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase
keywords: Amperometric biosensor; Gold nanoparticles; H(2)O(2); Hybrid sphere; Self-assembly of dipeptide