Plasmonic enhancement of nitric oxide generation.

While the utility of reactive oxygen species in photodynamic therapies for both cancer treatments and antimicrobial applications has received much attention, the inherent potential of reactive nitrogen species (RNS) including nitric oxide (NO˙) for these applications should not be overlooked. In recent years, NO˙ donor species with numerous-including photodynamic-mechanisms have been classified with efficacy in antimicrobial and therapeutic applications. While properties of NO˙ delivery may be tuned structurally, herein we describe for the first time a method by which photodynamic NO˙ release is amplified simply by utilizing a plasmonic metal substrate.

Development of a Microplate Platform for High-Throughput Sample Preparation Based on Microwave Metasurfaces.

Sample preparation is one of the most time-consuming steps in diagnostic assays, particularly those involving biological samples. In this paper we report the results of finite-difference time-domain (FDTD) simulations and thermographic imaging experiments carried out with the intent of designing a microplate for rapid, high-throughput sample preparation to aid diagnostic assays. This work is based on devices known as microwave lysing triangles (MLTs) that have been proven capable of rapid sample preparation when irradiated in a standard microwave cavity.

Carbon Nanodots in Photodynamic Antimicrobial Therapy: A Review.

Antibiotic resistance development in bacteria is an ever-increasing global health concern as new resistant strains and/or resistance mechanisms emerge each day, out-pacing the discovery of novel antibiotics. Increasingly, research focuses on alternate techniques, such as antimicrobial photodynamic therapy (APDT) or photocatalytic disinfection, to combat pathogens even before infection occurs. Small molecule "photosensitizers" have been developed to date for this application, using light energy to inflict damage and death on nearby pathogens via the generation of reactive oxygen species (ROS).

Fluorophore-Induced Plasmonic Current: Generation-Based Detection of Singlet Oxygen.

In this work, we report the surface-based electrical detection of singlet oxygen using the emerging fluorophore-induced plasmonic current (PC) technique. By this method, we utilize the fluorescent "turn on" response of the well-known singlet oxygen sensor green (SOSG) singlet oxygen (O) fluorescent probe for the generation of fluorophore-induced PC in a silver nanoparticle film. To demonstrate the potential utility of this new technique, a photosensitizing molecule is used to generate O in a solution containing the SOSG probe.

Spectral Distortions in Zinc-based Metal-Enhanced Fluorescence Underpinned by Fast and Slow Electronic Transitions.

Metal-enhanced fluorescence (MEF) is a promising technology with impact in diagnostics, electronics, and sensing. Despite investigation into MEF fundamentals, some properties remain unresearched, notably spectral distortion. To date, publications have described its underpinnings, yet comprehensive analysis is needed, as presented recently for silver films.

Spectral Distortions in Metal-Enhanced Fluorescence: Experimental Evidence for Ultra-Fast and Slow Transitions.

Metal-enhanced fluorescence (MEF) has become an increasingly important technology in recent years, with thorough research addressing the fundamentals of MEF. In many studies, spectral distortion is observed in the enhanced spectra as compared to free-space fluorescence emission profiles. Despite this observation, very little experimentation has been undertaken to investigate the mechanistic underpinnings of spectral distortion in MEF.

Low-concentration trypsin detection from a metal-enhanced fluorescence (MEF) platform: Towards the development of ultra-sensitive and rapid detection of proteolytic enzymes.

Proteolytic enzymes, which serve to degrade proteins to their amino acid building blocks, provide a distinct challenge for both diagnostics and biological research fields. Due to their ubiquitous presence in a wide variety of organisms and their involvement in disease, proteases have been identified as biomarkers for various conditions. Additionally, low-levels of proteases may interfere with biological investigation, as contamination with these enzymes can physically alter the protein of interest to researchers, resulting in protein concentration loss or subtler polypeptide clipping that leads to a loss of functionality.

Silvered conical-bottom 96-well plates: enhanced low volume detection and the metal-enhanced fluorescence volume/ratio effect.

Many diagnostic fluorescence assays are limited by sensitivity (signal/noise) and minimum sample volume requirements. Herein we report a new, silvered conical-bottom 96-well plate platform used to increase the detectability from very small volumes of micromolar concentrations of fluorophores. This technology employs the principles of metal-enhanced fluorescence (MEF), which is the process by which fluorescence emission is amplified in the near-field of plasmonic nanoparticles.

Heavy carbon nanodots 2: plasmon amplification in Quanta Plate™ wells and the correlation with the synchronous scattering spectrum.

Brominated carbon nanodots are a new carbon nanostructure that exhibits strong phosphorescence without fixation. Herein we report plasmonic amplification of this phosphorescence in silver-coated Quanta Plate™ wells, a technique called metal-enhanced phosphorescence (MEP). Subsequently we correlate the excitation and emission components of brominated carbon nanodots to their respective enhancement values.

Heavy carbon nanodots: a new phosphorescent carbon nanostructure.

Carbon nanodots are nanometer sized fluorescent particles studied for their distinct photoluminescent properties and biocompatibility. Although extensive literature reports the modification and application of carbon nanodot fluorescence, little has been published pertaining to phosphorescence emission from carbon nanodots. The use of phosphors in biological imaging can lead to clearer detection, as the long lifetimes of phosphorescent emission permit off-gated collection that avoids noise from biological autofluorescence.