The Influence of Silver Nanostructures Formed in situ in Silica Sol–Gel Derived Films on the Rate of Förster Resonance Energy Transfer

Abstract

The efficiency of Förster resonance energy transfer (FRET) can be enhanced in the presence of a metal. Herein, we demonstrate the increased efficiency for a novel model sensor system where FRET is shown to occur between Rhodamine 6G in the bulk sol-gel matrix and Texas Red, which is held a fixed distance away by covalent attachment onto a silane spacer. Silver colloids are formed using light to initiate the reduction of a silver salt, which can be achieved at controlled locations within the film. Both the fluorescence intensity and lifetime maps and analysis indicate that an enhanced FRET efficiency has been achieved in the presence of silver nanoparticles. An increase in efficiency of 1.2-1.5 times is demonstrated depending on the spacer used. The novelty of our approach lies in the method of silver-nanoparticle formation, which allows for the accurate positioning of the silver nanoparticles and hence selective fluorescence enhancement within a biocompatible host material. Our work gives a practical demonstration of metal-enhanced FRET and demonstrates the ability of such systems to be developed for molecular-recognition applications that could find use in lab-on-a-chip technologies.

Silver Decahedral Nanoparticles-Enhanced Fluorescence Resonance Energy Transfer Sensor for Specific Cell Imaging

“…Nevertheless, signal amplification for FRET-based methods to attain higher sensitivity in cell imaging has not been investigated yet. Silver nanomaterials were reported to enhance the FRET efficiency and result in increased quantum yield and emission intensity of fluorophores. − We have developed a sensitive silver-enhanced FRET sensor for protein detection . Silver-enhanced FRET sensors might have the potential to enhance the sensitivity of FRET imaging of cells.…”

Silver Nanoparticle-Enhanced Fluorescence Resonance Energy Transfer Sensor for Human Platelet-Derived Growth Factor-BB Detection

“…Quantum dots have fluorescent properties and can also be a donor or acceptor in FRET systems, − whereas gold nanoparticles are regularly used as acceptors to quench the fluorescence response of the fluorophores. − Silica , and polymer particles − have been used as shells to incorporate fluorescent dyes to form fluorescent nanoparticles that make the FRET systems water dispersible as well as to enhance fluorescent brightness and photostability. On the other hand, silver nanoparticles could enhance the FRET efficiency through silver-fluorophore interaction, leading to an increase in quantum yield and emission intensity of the fluorophore. − Holmes-Smith showed that the silver nanostructures enhance the efficiency of FRET between donor molecule (Rhodanmine 6G) and acceptor molecule (Texas Red). Although the phenomenon of silver-enhanced FRET efficiency has been reported, there is very limited progress in the development of bioanalytical methods for the detection of proteins using this approach.…”

“…On the other hand, silver nanoparticles could enhance the FRET efficiency through silver-fluorophore interaction, leading to an increase in quantum yield and emission intensity of the fluorophore. 23−25 Holmes-Smith 26 showed that the silver nanostructures enhance the efficiency of FRET between donor molecule (Rhodanmine 6G) and acceptor molecule (Texas Red). Although the phenomenon of silver-enhanced FRET efficiency has been reported, there is very limited progress in the development of bioanalytical methods for the detection of proteins using this approach.…”