Achieving high-purity colloidal gold nanoprisms and their application as biosensing platforms

• Published in: Journal of colloid and interface science Vol. 348; no. 1; pp. 29 - 36
• Main Authors: Guo, Zhirui, Fan, Xu, Liu, Lianke, Bian, Zhiping, Gu, Chunrong, Zhang, Yu, Gu, Ning, Yang, Di, Zhang, Jinan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.08.2010; Elsevier
• Subjects: Animals; Anisotropic shape; Antigen-Antibody Complex - analysis; Antigen-Antibody Reactions; Biosensing Techniques - methods; Biosensor; Chemistry; Colloidal state and disperse state; Electrostatic interaction; Exact sciences and technology; General and physical chemistry; Gold; Gold Colloid; Humans; Materials Testing; Nanostructure; Optics and Photonics; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Surface Plasmon Resonance - instrumentation; Anisotropic shape; Gold; Nanostructure; Biosensor; Electrostatic interaction; Shape; Nanoparticle; Infrared absorption; Purity; Potential; Precipitate; Aggregation; Optical properties; Structure; Stability; Antibody; Transition metal; Surface plasmon; X ray diffraction; Antigen; Thickness; Transmission electron microscopy; Resonance; Electrostatics; Recognition; Ultraviolet visible spectrometry
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2010.04.013

High-purity colloidal gold nanoprisms (∼97%) were achieved by exploiting the electrostatic aggregation and shape effects through a seed-mediated, iodide ion- and CTABr-assisted synthetic system and used for biosensing in solution. Gold nanoprisms with average edge size of ∼140 nm and thickness of ∼8 nm were achieved in high-purity (∼97%) by exploiting the electrostatic aggregation and shape effects through a modified seed-mediated approach. The proposed strategy lies in the dramatically different stability and aggregation potential between the produced gold nanoprisms and spherical gold nanoparticles, which can be modulated by varying the anion concentration in the reaction solution. Hence, the gold nanoprisms spontaneously aggregated into precipitate whereas most of the spherical ones were still kept in the solution. Moreover, this strategy is also flexible enough that ultra-small gold nanoprisms with average width less than 50 nm can be collected in good-purity. The structure and optical properties of these nanoprisms have been studied by TEM, SAED, XRD and UV–vis–NIR spectroscopy, respectively. These high-purity colloidal gold nanoprisms exhibit remarkably enhanced surface plasmon resonance (SPR) as well as strong near-infrared absorption. Furthermore, we have also investigated their potential for biosensing based on the sensitive changes of SPR band induced by the antibody–antigen recognition events. The experimental results clearly suggest that gold nanoprisms can be a promising nanostructured system for plasmonic sensor applications.