Plasmon-Coupled Silver Nanoparticles for Mobile Phone-Based Attomolar Sensing of Mercury Ions

Abstract

The ability of plasmonic nanoparticles (NPs) to focus the impinging electromagnetic (EM) radiation to subwavelength regimes assists in the detection of molecules at extremely low concentrations. Numerous nanomaterials have been exploited in the surface plasmon-coupled emission (SPCE) technology, presenting quintessential physicochemical insights. However, seldom attention has been paid toward utilizing the biocompatible nanotechnology for substrate nanoengineering in SPCE. In this context, we present LYCOAT-based silver (Ag) NPs synthesized via a frugal disruptive approach by exposing a simple physical mixture of Ag+ ions and LYCOAT to UV irradiation. Variations in the time of UV exposure resulted in nanofractals and nanocubes of Ag presenting unique architectures for nanophotonic applications, where the biocompatible LYCOAT functions as both reducing and capping agents under ambient conditions. Nanomaterials synthesized in this approach were studied in spacer, cavity, and extended cavity nanointerfaces in the SPCE platform for obtaining tunable plasmonic coupling. The augmented >900-fold SPCE enhancements were utilized for mobile phone-based attomolar sensing of environmentally hazardous Hg2+ ions. The simple, realistic, and eco-friendly methodology adopted here for developing nanomaterials for photonic applications opens the door for exploring such next-generation bio-inspired nanomaterials for point-of-care diagnostic applications.

Cellphone-Aided Attomolar Zinc Ion Detection Using Silkworm Protein-Based Nanointerface Engineering in a Plasmon-Coupled Dequenched Emission Platform

“…24 Although a variety of such NPs are explored in different platforms, the utility of anisotropic AgNPs is seldom reported in the SPCE platform. Recently, we presented the utility of Ag nanofractals 46 and soret nanoassemblies 22 for attomolar and femtomolar sensing of mercury ions and glutathione, respectively. However, the SPCE enhancements obtained from these nanoengineering strategies have not been adequate.…”

Multiarchitecture-Based Plasmonic-Coupled Emission Employing Gold Nanoparticles: An Efficient Fluorescence Modulation and Biosensing Platform

“…Next, 1 mM rhodamine B (RhB, Sigma-Aldrich) in a poly­(vinyl alcohol) (PVA, Alfa) solution was spin-coated onto the AuNP-covered substrate and dried in air to obtain a fluorophore-doped substrate. For the spin-coating method, AuNPs and RhB were both dissolved in PVA and then spin-coated on the gold substrate in three different structures: spacer, extended cavity, and cavity. ,, Spacer structure: the AuNP-PVA solution was spin-coated between the gold substrate and the fluorophore layer as the spacer layer. Extended cavity: the AuNP layer was spin-coated on top of the fluorophore layer.…”

“…For the spin-coating method, AuNPs and RhB were both dissolved in PVA and then spin-coated on the gold substrate in three different structures: spacer, extended cavity, and cavity. 17,31,32 Spacer structure: the AuNP-PVA solution was spin-coated between the gold substrate and the fluorophore layer as the spacer layer. Extended cavity: the AuNP layer was spin-coated on top of the fluorophore layer.…”

Sericin-Based Bio-Inspired Nano-Engineering of Heterometallic AgAu Nanocubes for Attomolar Mefenamic Acid Sensing in the Mobile Phone-Based Surface Plasmon-Coupled Interface

“…A similar pattern in the size distribution has been observed in earlier works and is attributed to the anisotropy in the structural morphology. 13,17,21 Consequently, light scattering contributed by such anisotropic NPs presents distinct signals in DLS due to their translational as well as rotational diffusion in the liquid phase. The size distribution signal occurring at lower and higher values is on account of the rotational diffusion and translational diffusion, respectively.…”