Studies of Surface-Adsorbed Fluorescently Labeled Casein and Concanavalin A Using Surface Plasmon-Coupled Emission

Abstract

We report the use of surface plasmon-coupled emission (SPCE) as an analytical tool to study the photophysics of surface-adsorbed fluorescently labeled proteins. The study uses plasma etching of PMMA surface followed by deposition of poly(diallyldimethylammonium chloride) (PDDA) for surface protein detection. PDDA increases the overall amount of the captured protein and also promotes dye aggregation. The photon-sorting properties of the SPCE process allows for wavelength separation of the individual components from the protein-dye aggregates. This has been exploited to study the fluorescence emissions from casein labeled with fluorescein isothiocyanate and concanavalin A labeled with tetramethylrhodamine. Based on the current findings, the proteins can be used to measure background fluorescence or to monitor the microenvironments in fluoroimmunoassays on SPCE substrates.

Amplification of Surface Plasmon Coupled Emission from Graphene–Ag Hybrid Films

“…15 In addition, the use of incident light whose energy matched the excitation maximum of the fluorophore has also been explored, and notable progress toward the development of low-cost sensing platforms has been reported. 16 Lastly, it should be mentioned that the use of specially engineered conical mirrors for efficient signal collection can further enhance the performance of SPCE sensors, albeit the associated high cost restricts its use in highly specialized applications. 17 It is important to note that in refs 15−18 the enhanced detection stemmed from factors that are extraneous to the SPCE substrate.…”

“…In this regard, signal enhancement due to efficient fluorescence–plasmon coupling using index matching fluids which also result in a uniform refractive index medium for the light to pass through were explored . In addition, the use of incident light whose energy matched the excitation maximum of the fluorophore has also been explored, and notable progress toward the development of low-cost sensing platforms has been reported . Lastly, it should be mentioned that the use of specially engineered conical mirrors for efficient signal collection can further enhance the performance of SPCE sensors, albeit the associated high cost restricts its use in highly specialized applications …”

Wood Microfluidics

“…We were able to produce different device designs, such as T-/Y-channel mixers, single channels capable of bearing a fluid path for surface plasmon-coupled enhanced (SPCE) fluorescence and detection of microbial contamination using resazurin. A primary focus for this manuscript was to demonstrate the use of POC wood chips for protein detection via SPCE. − SPCE has gained a lot of attention in the past decade because of its ability to address inherent drawbacks of conventional fluorescence particularly when the fluorophore has a low quantum yield. Fluorescence based detection has hugely impacted the current generation of biomedical, diagnostic and sensing devices .…”

Novel Synthesis of Nanoparticles for Enhancements in Surface Plasmon Coupled Emission

“…Enhancement in the fluorescence emission was calculated as the ratio of intensities of SPCE and Free Space (FS) at a particular wavelength. Conventional SPCE could enhance the fluorescence by 10-15 fold [6,7]. However, the enhancements obtained in the presence of SnSe and SnTe spacer layers were 32 and 43 fold respectively (Fig.…”