Large-Area Silver–Stibnite Nanoporous Plasmonic Films for Label-Free Biosensing

Abstract

The development of various plasmonic nanoporous materials has attracted much interest in different areas of research including bioengineering and biosensing because of their large surface area and versatile porous structure. Here, we introduce a novel technique for fabricating silver-stibnite nanoporous plasmonic films. Unlike conventional techniques that are usually used to fabricate nanoporous plasmonic films, we use a room-temperature growth method that is wet-chemistry free, which enables wafer-scale fabrication of nanoporous films on flexible substrates. We show the existence of propagating surface plasmon polaritons in nanoporous films and demonstrate the extreme bulk refractive index sensitivity of the films using the Goos-Hänchen shift interrogation scheme. In the proof-of-concept biosensing experiments, we functionalize the nanoporous films with biotin-thiol using a modified functionalization technique, to capture streptavidin. The fractal nature of the films increases the overlap between the local field and the immobilized biomolecules. The extreme sensitivity of the Goos-Hänchen shift allows femtomolar concentrations of streptavidin to be detected in real time, which is unprecedented using surface plasmons excited via the Kretschmann configuration.

Phase‐Change‐Material‐Based Low‐Loss Visible‐Frequency Hyperbolic Metamaterials for Ultrasensitive Label‐Free Biosensing

“…Since the GH shift strongly depends on the substrate dielectric constant, we developed a sensor platform based on the proposed prism‐coupled HMM system. The configuration used for sensing purposes is shown in Figure b essentially, a polydimethylsiloxane (PDMS) channel with dimension 0.7 × 0.7 × 0.2 cm 3 was attached to the prism coupled HMM system.…”

“…The configuration used for sensing purposes is shown in Figure b essentially, a polydimethylsiloxane (PDMS) channel with dimension 0.7 × 0.7 × 0.2 cm 3 was attached to the prism coupled HMM system. For the GH shift measurements, a home‐built differential phase‐sensitive set up was used . As a first step, the sensor device was calibrated by performing the bulk refractive index sensing, which was done by injecting different weight ratios (1% to 10% w/v) of aqueous solutions of glycerol with known refractive indices.…”

Hyperbolic dispersion metasurfaces for molecular biosensing

“…To validate this tunable behavior experimentally, RI sensing has been performed because the G-H shift strongly depends on the superstrate RI. A differential phase-sensitive setup to record the GH shifts has been used [133][134][135]. In the experiments, the G-H shifts have been monitored, by injecting different weight ratios (1-10% w/v) of aqueous solutions of glycerol with known refractive indices into sensor channel.…”

Plasmonic Light Trapping in Titania–Silver Dots Thin Films

“…[1,2] Due to this function, nanostructured materials have the potential to play a very important role in various application fields, [3] such as colorimetric sensors, [4] data storage, [5] and biomedical diagnostic applications. [6] Because shape and position of LSPR peak depend not only on NPs material, size, and shape but also on surrounding medium, [7] various nanostructures have been synthesized and used to modulate LSPR among these NPs, [8] nanorods, [9] nanoporous films, [10] and nanohole arrays. [11] Nowadays, plasmonic metamaterials (metal-dielectric compounds) with peculiar optical properties such as the modulation of plasmonic resonance, constitute a very intriguing research field for their applications.…”