Photonic resonator absorption microscopy: why consider metallic and magneto-plasmonic nano-assemblies over bare nanoparticles for digital biosensing?

The unique optical interaction of species such as nanomaterials, proteins, viruses, antibodies, microRNA, and exosomes with the one-dimensional grating-based photonic crystals (PCs) has been leveraged in their detection using photonic crystal absorption microscopy (PRAM). While the principle and fundamental mechanism of such interfacial interactions are well delineated using wavelength and intensity modulations associated with the guided-mode resonance (GMR) of the PC, the effect of nano-assemblies in place of nanoparticles (NPs) has not been reported previously. In this work, the fundamental limitations observed with pristine NPs are overcome through the use of tunable AuNP assemblies synthesized via adiabatic cooling technology, where tunable nano-assemblies are obtained by subjecting the respective NPs to - 196 °C.

Photonic Crystal Enhanced Microscopy on a 2D Photonic Crystal Surface.

Digital-resolution biosensing based on resonant reflection from photonic crystals (PC) has demonstrated significant potential for detection of proteomic and genomic biomarkers in serology, infectious disease diagnostics, and cancer diagnostics. An important intrinsic characteristic of resonant metamaterial surfaces is that enhanced electromagnetic fields are not uniformly distributed, resulting in spatially variable light-matter interactions with nanoparticle tags that signal the presence of biomarker molecules. In this work, we compare the spatial uniformity of resonantly enhanced, surface-confined electromagnetic fields of a one-dimensional (1D) PC with a two-dimensional (2D) PC with fourfold symmetry.

Photonic Crystal Grating Resonance and Interfaces for Health Diagnostic Technologies.

The photonic crystal grating resonance (PCGR) technologies mark a significant advancement in early diagnostics of infectious diseases. Here we review the historical perspectives of the PCGR-based platform starting from the early 1900s, discussing the fundamental principles, fabrication strategies, properties, and multifaceted applications. We delve into the significance of grating-based PC interfaces, from the perspective of plasmonics, photonics, and hybrid photoplasmonic interfaces.

Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review.

The careful arrangement of nanomaterials (NMs) holds promise for revolutionizing various fields, from electronics and biosensing to medicine and optics. This review delves into the intricacies of nano-assembly (NA) techniques, focusing on oriented-assembly methodologies and stimuli-dependent approaches. The introduction provides a comprehensive overview of the significance and potential applications of NA, setting the stage for review.

Floral Extract-Based Biosynthesis for Enhanced Surface Plasmon-Coupled Emission and a Preliminary Study on Fluoroimmunoassay.

We demonstrate the synthesis of biogenic supported silver spiked star architectures and their application to increase the electromagnetic field intensity at its tips that enhance plasmon-coupled emission. floral extract has been used to synthesize silver nanocubes and spiked stars. We observe ∼445-fold and ∼680-fold enhancements in spacer and cavity configurations, respectively, in the SPCE platform.

Review of Gold Nanoparticles in Surface Plasmon-Coupled Emission Technology: Effect of Shape, Hollow Nanostructures, Nano-Assembly, Metal-Dielectric and Heterometallic Nanohybrids.

Point-of-care (POC) diagnostic platforms are globally employed in modern smart technologies to detect events or changes in the analyte concentration and provide qualitative and quantitative information in biosensing. Surface plasmon-coupled emission (SPCE) technology has emerged as an effective POC diagnostic tool for developing robust biosensing frameworks. The simplicity, robustness and relevance of the technology has attracted researchers in physical, chemical and biological milieu on account of its unique attributes such as high specificity, sensitivity, low background noise, highly polarized, sharply directional, excellent spectral resolution capabilities.

Smartphone-Based Attomolar Cyanide Ion Sensing Using Au-Graphene Oxide Cryosoret Nanoassembly and Benzoxazolium-Based Fluorophore in a Surface Plasmon-Coupled Enhanced Fluorescence Interface.

Photoplasmonic platforms are being demonstrated as excellent means for bridging nanochemistry and biosensing approaches at advanced interfaces, thereby augmenting the sensitivity and quantification of the desired analytes. Although resonantly coupled electromagnetic waves at the surface plasmon-coupled emission (SPCE) interface are investigated with myriad nanomaterials in order to boost the detection limits, rhodamine moieties are ubiquitously used as SPCE reporter molecules in spite of their well-known limitations. In order to overcome this constraint, in this work, a benzoxazolium-based fluorescent molecule, ()-2-(4-(dimethylamino)styryl)-3-methylbenzo[]oxazol-3-ium iodide (), was synthesized to selectively detect the cyanide (CN) ions in water samples.

Photonic Crystal Enhanced Fluorescence: A Review on Design Strategies and Applications.

Nanoscale fluorescence emitters are efficient for measuring biomolecular interactions, but their utility for applications requiring single-unit observations is constrained by the need for large numerical aperture objectives, fluorescence intermittency, and poor photon collection efficiency resulting from omnidirectional emission. Photonic crystal (PC) structures hold promise to address the aforementioned challenges in fluorescence enhancement. In this review, we provide a broad overview of PCs by explaining their structures, design strategies, fabrication techniques, and sensing principles.

Biosensing Technologies: A Focus Review on Recent Advancements in Surface Plasmon Coupled Emission.

In the past decade, novel nano-engineering protocols have been actively synergized with fluorescence spectroscopic techniques to yield higher intensity from radiating dipoles, through the process termed plasmon-enhanced fluorescence (PEF). Consequently, the limit of detection of analytes of interest has been dramatically improvised on account of higher sensitivity rendered by augmented fluorescence signals. Recently, metallic thin films sustaining surface plasmon polaritons (SPPs) have been creatively hybridized with such PEF platforms to realize a substantial upsurge in the global collection efficiency in a judicious technology termed surface plasmon-coupled emission (SPCE).

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

Engineering photo-plasmonic platforms with heterometallic nanohybrids are of paramount significance for realizing augmented sensitivity in fluorescence-based analytical detection. Although myriad nanomaterials with versatile functionalities have been explored in this regard in the surface plasmon-coupled emission (SPCE) interface, light harvesting using nano-antennas synthesized via sustainable bio-inspired routes still remains a high priority in current research. Our study provides a rational design for in situ fabrication of nanoparticles of silver, gold, and their plasmonic hybrids using biocompatible, non-hazardous sericin protein (obtained ) as the reducing and capping agent.

Metal-Free, Graphene Oxide-Based Tunable Soliton and Plasmon Engineering for Biosensing Applications.

The quest for auxiliary plasmonic materials with lossless properties began in the past decade. In the current study, a unique plasmonic response is demonstrated from a stratified high refractive index (HRI)-graphene oxide (GO) and low refractive index (LRI)-polymethyl methacrylate (PMMA) multistack. Graphene oxide plasmon-coupled emission (GraPE) reveals the existence of strong surface states on the terminating layer of the photonic crystal (PC) framework.

Superior Resonant Nanocavities Engineering on the Photonic Crystal-Coupled Emission Platform for the Detection of Femtomolar Iodide and Zeptomolar Cortisol.

Although luminescence spectroscopy has been a promising sensing technology with widespread applications in point-of-care diagnostics and chem-bio detection, it fundamentally suffers from low signal collection efficiency, considerable background noise, poor photostability, and intrinsic omnidirectional emission properties. In this regard, surface plasmon-coupled emission, a versatile plasmon-enhanced detection platform with >50% signal collection efficiency, high directionality, and polarization has previously been explored to amplify the limit of detection of desired analytes. However, high Ohmic loss in metal-dependent plasmonic platforms has remained an inevitable challenge.

Femtomolar Detection of Spermidine Using Au Decorated SiO Nanohybrid on Plasmon-Coupled Extended Cavity Nanointerface: A Smartphone-Based Fluorescence Dequenching Approach.

Coupling of photons with molecular emitters in different nanocavities have resulted in transformative plasmonic applications. The rapidly expanding field of surface plasmon-coupled emission (SPCE) has synergistically employed subwavelength optical properties of localized surface plasmon resonance (LSPR) supported by nanoparticles (NPs) and propagating surface plasmon polaritons assisted by metal thin films for diagnostic and point-of-care analysis. Gold nanoparticles (AuNPs) significantly quench the molecular emission from fluorescent molecules (at close distances <5 nm).

Disulphide linkage: To get cleaved or not? Bulk and nano copper based SERS of cystine.

Different nano-structures of noble metals have been the conventional substrates for carrying out Surface Enhanced Raman Spectroscopy (SERS). In this paper we examine electrodeposited copper (Cu) nano-structures on pencil graphite as novel substrate to carry out SERS measurements by considering l-cystine (Cys-Cys) (dimer of the amino acid cysteine) as the probe. The formation of monolayer of the probe molecule on the substrates was confirmed using cyclic voltammetric measurements.

Correction: The photocatalytic role of electrodeposited copper on pencil graphite.

Correction for 'The photocatalytic role of electrodeposited copper on pencil graphite' by Arathi P. J. et al.

The photocatalytic role of electrodeposited copper on pencil graphite.

We report on the ability of template-electrodeposited copper on pencil graphite as a novel and cost effective photocatalyst by considering the photodimerization of p-aminothiophenol (p-ATP) to 4,4'-dimercaptoazobenzene.