In a study published recently in the Journal Materials Chemistry and Physics, the economical and cost-effective one-pot manufacturing of AgAu nanohybrids via ultraviolet light without the usage of ecologically toxic chemicals is discussed.
Study: Gelucire®-mediated heterometallic AgAu nanohybrid engineering for femtomolar cysteine detection using smartphone-based plasmonics technology. Image Credit: one photo/Shutterstock.com
What is Fluorescence?
Analytical and empirical research in the field of luminescence has shown an attractive and feasible domain for laboratory testing, mineralogy, microscopy, geographical evaluation, and biosensing during the last several years.
The interesting properties of light-matter connections, in which light is absorbed by chromophores and then emitted by fluorescent dyes, have triggered a radical shift, likely to result in the fluorescence-based detection methods being widely seen in a variety of applications ranging from specialized healthcare diagnostics to many on-field bio-sensing strategies.
Considering its ubiquitous usage, fluorescence's isotopic composition restricts its collecting effectiveness.
Advantages of Plasmonic Nanoparticles
The current understanding of light mandates that photon transmission is an intrinsic property of fluorescence.
This is true under optimal conditions, but fluorescence intensity is substantially affected by its surroundings in practice.
Photocatalysis, optoelectronic devices, surface enhanced-Raman scattering, and solar panels have all benefited from the distinctive attributes of plasmonic nanoparticles.
Plasmonic nanoparticles (NPs) have localized surface plasmon resonance (LSPR), which allows for increased Electromagnetic field strength in the near-field region.
Local electric field enhancement by plasmonic nanoparticles has recently been explored using different dielectric nanoparticles. Because of the massive photocatalytic activity, these techniques have improved the responsiveness of analytes.
Plasmon-Enhanced Fluorescence (PEF)
Fluorophores in close vicinity to plasmonic nanoparticles exhibit intriguing properties such as enhanced radiative decay rate, light absorption, and shorter lifespan. This effect is known as metal-enhanced fluorescence (MEF) or plasmon-enhanced fluorescence (PEF). Despite the increased emission achieved with MEF due to the creation of so-called EM'hotspots,' there are downsides such as poor absorption rate, analytical artifacts, and cooling.
Nanoparticle Techniques and Fluorescence
Recently, self-assembled nano-sorets, low dimensional-metallic nanohybrids, and metal-dielectric nanohybrids using silver as the dominant plasmonic element have all been investigated for this goal.
Even with their versatile properties like top-notch stability, excellent biocompatibility, and extraordinary convenience in the biological synthesis process, as well as configurable optical and electrical efficiency in observable and near-infrared optical areas, gold (Au) nanoparticles have not been thoroughly researched in SPCE.
The main reason for this is the massive cross-conductive inefficiencies that result in luminescence dampening. Non-radiative routes are created when luminous moieties are coupled to elevated plasmonic events.
In this context, nanomaterials with plasmonic holes that exhibit inter-plasmon interaction that aid in enhancing stacked phases have been explored.
In recent years, many ways to signal dequenching in the vicinity of silver nanoparticles have been conceptually and empirically proved. Some of these are (i) fundamental metallic arrangements, (ii) asymmetric nanoparticles with pointy ends, (iii) AuNP painted on insulating nanoparticles, and (iv) nanogaps in arrays with gap-based micro with strong spots.
Despite numerous tactics utilized in the past, the SPCE improvements attained via these techniques stay 200-fold.
Effectiveness of Gelucire®
To date, many solutions for resolving the burning phenomena found in silver nanoparticles have been investigated.
The SPCE improvements attained with these tactics have been modest. Furthermore, the majority of these approaches need the usage of toxic compounds throughout the catalytic process.
This behavior harms the ecosystem and might have serious consequences from an environmental viewpoint. In this light, it has become vital to investigate approaches that exhibit significant SPCE improvement while still being environmentally friendly.
From this vantage point, the usefulness of Gelucire® was investigated, a nontoxic plastic widely utilized in the biomedical field. Only Ultraviolet light and Gelucire® were employed to obtain nanoparticles, reducing the need for ecologically toxic materials.
Research Findings and Conclusions
The utilization of asymmetric AgAu nanocomposites enabled extraordinary >1000-fold SPCE increases in the exterior hole nanointerface.
The nanogaps' substantial increase in magnified hotspots was subsequently used to identify cysteine at the femtomolar threshold.
The signaling research was carried out with the use of a limited mobile phone SPCE technology. This technology has streamlined detection systems and made them more accessible, particularly to those at the bottom of the scale.
Because of the biological properties of these synthesized nanoparticles, it is expected that this technology will find extensive use in several research domains, particularly in the area of point-of-care diagnosis for a variety of illnesses, offering close to real-time control strategies.
Continue reading: Understanding Plasmonic Nanoantennas.
Rai, A. et al. (2022). Gelucire®-mediated heterometallic AgAu nanohybrid engineering for femtomolar cysteine detection using smartphone-based plasmonics technology. Materials Chemistry and Physics. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0254058422000530