A Localized Surface Plasmon Resonance Biosensor Based on Integrated Controllable Au2S/AuAgS-Coated Gold Nanorods Composite

Abstract

In this work, we have demonstrated that the exquisite optical properties based on localized surface plasmon resonance (LSPR) of Au 2 S/AuAgS-coated gold nanorods (Au 2 S/AuAgS-coated GNRs) can be utilized to develop a simple and sensitive biosensor, and goat antihuman IgG can be detected by the human IgG probe as low as 0.2 nM. Moreover, we introduce an integrated LSPR biosensor constructed by integrating Au 2 S/AuAgS-coated GNRs immobilized on glass slide and isolated Au 2 S/ AuAgS-coated GNRs in the form of liquid. The detection of target binding was performed via direct spectral changes induced by changes of refractive index in the vicinity of individual particles. The integrated LSPR optical biosensor is label-free, cost-effective, and easy to fabricate and requires only a visible/near-infrared spectrometer for detection purposes. Additionally, the investigation on the mutual influence of the two types of nanorods in the integrated LSPR biosensor was performed. The results of separate experiments indicate that the nanorods in the form of isolate or in integrated exhibit a similar behavior.

Enhanced Infrared LSPR Sensitivity of Cap-Shaped Gold Nanoparticles Coupled to a Metallic Film

“…As is well documented, nanoparticles having pointed structures with a generally elongated shape have superior refractive index sensitivity. 17,18,29,48 Silver exhibits greater sensitivity than gold because the imaginary component of its complex dielectric constant is lower, particularly at shorter wavelengths.…”

“…Early works made use of colloidal nanoparticles 12,15,23 or nanoparticles with shapes other than spheres such as rods and prisms. 17,18,20 Some others have made use of island structures prepared by thermal deposition of noble metal, followed by annealing. 19 More recently electron beam lithography is used widely.…”

Correlating the structure and localized surface plasmon resonance of single silver right bipyramids

“…In particular, the localized surface plasmon resonance (LSPR) properties of noble metal (Ag and Au, for example) particles have shown promise for use in information [1][2][3][4][5] and sensing [6][7][8][9][10][11] applications. The enhanced electromagnetic fields around a particle due to LSPR excitation have been used for surface-enhanced Raman spectroscopy (SERS) [12][13][14], while the resulting optical properties of such particles make them attractive for a variety of chemical [15][16][17][18] and biological detection schemes [11,[19][20][21][22][23][24], some of which have been commercialized and FDA-cleared. In addition, they exhibit bright, environment-dependent light scattering and absorption, leading to their use as nanoscale refractive index sensors [6,19,[25][26][27].…”

Sythesis, Modification, and Biosensing Characteristics of Au2S/AuAgS‐Coated Gold Nanorods

“…Finally, 0.1 mL seed solution was added to the growth solution and the reaction mixture was gently agitated for 20 s and left undisturbed overnight. [27,28], a modified strategy is used to coat a chalcogenide layer on the surface of GNRs. The Au 2 S/AuAgS/GNRs were prepared by adding Na 2 S 2 O 3 (0.055 mL, 1.0 M) solution into 5 mL of the as-synthesized gold nanorods at room temperature, heated, and kept at 50 ∘ C with different reaction time ranging from 20 s to 3 h. Then the mixture of GNRs and Na 2 S 2 O 3 was taken out, cooled to room temperature, followed by centrifugation at 10000 rpm for 20 min, and redispersed in 5 mL water.…”