title: Gold nanorod biochip functionalization by antibody thiolation.
abstract: Conjugation of biomolecules on gold nanorod (GNR) surfaces is the basis for successful applications in biosensing, imaging, and drug delivery. Current functionalization methods are often problematic, involving multi-step nanoparticle modification to replace surfactant bilayer, delicate nanoparticle protection during surfactant exchange, and material loss due to inevitable aggregation. Instead of intensive surface modification of GNRs, we describe herein a facile method to functionalize gold nanorod surfaces via covalent Au-S bonds by thiolating receptors. The resulting GNR-bioconjugates showed superior dispersion and stability in buffer for months without morphology change and aggregation. ELISA tests confirmed the high biofunctionality of the thiolated anti-IgG moieties immobilized on the GNR surfaces. Furthermore, this simple method facilitated a straightforward functionalization of GNR assembly on glass substrate to construct a specific biochip, which can detect human IgG targets in a label-free fashion with high sensitivity and specificity. Compared to electropolymeric coating to functionalize the GNR, our method exhibited a five-fold enhancement in the spectral sensitivity to refractive index change caused by the target binding. This universal GNR bioconjugation method can be extended to bind different proteins and antibodies for development of biosensors or drug delivery.
authors.affiliation: Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA; Department of Central Laboratory, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Mei
authors.affiliation: Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA. Electronic address: liang.tang@utsa.edu.
authors.forename: Liang
authors.initials: L
authors.lastname: Tang
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000737:chemistry* / Q000276:immunology; D015374:Biosensing Techniques; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D043942:Nanotubes / Q000737:chemistry*; D040081:Protein Array Analysis; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D013438:Sulfhydryl Compounds; C048844:anti-IgG; D006046:Gold
keywords: Antibody thiolation; Biosensing; Gold nanorod biofunctionalization; Nano biochip; Surface plasmon resonance