Plasmon-enhanced fluorometry based on gold nanostructure arrays. Method and device

In this work, we describe a method of surface-enhanced fluorometry, based on the phenomenon of localized surface plasmon resonance in unordered gold nanostructure arrays. The theoretical approach for the model system “gold nanoparticle-dielectric spacer” in the electrostatic approximation by solution of Laplace’s equation is considered. The developed technology for manufacturing the plasmonic substrates as well as design of the novel laser-based compact fluorometer are presented. The arrays of gold nanostructures on solid substrates (nanochips) coated with different thicknesses of SiO₂ were developed and fabricated by thermal annealing of gold island films with subsequent dielectric spacer deposition. As an example for verification of the proposed method, the fluorescence properties of the system “gold nanostructures array – SiO₂ dielectric coating – Rhodamine 6G” were studied. It has been shown that enhancement of dye emission up to 22 times for dielectric coating with the thickness of about 20 nm is possible. Presented method is of importance for the development of the novel nanoscale sensors, biomolecular assays and nanoplasmonic devices

Preparation of Au Nanostructure Arrays for Fluorometry and Biosensors Applications

The paper describes the fabrication of random and ordered gold nanostructure arrays (NSA) of different morphology using island film thermal annealing and nanoimprint lithography techniques. Structural parameters of obtained NSA were investigated using atomic force microscopy method. Spectral characteristics of obtained NSA were studied in air atmosphere, and NSA light extinction spectra exhibited an expressed plasmon peak. Spectral position of localized surface plasmon resonance can be tuned depending on geometrical parameters of nanostructures, which is an important factor for resonant investigation methods of various types of molecular structures. Proposed technological approaches can be used to implement the resonance fluorometry in electromagnetic field of nanostructures (surface-enhanced fluorescence) method and in chemical and biosensors based on localized surface plasmon resonance. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3496

Smart nanocarriers for drug delivery: controllable LSPR tuning

Gold nanostructures are considered as a potential platform for building smart nanocarriers that will form the basis of novel methods of targeted delivery and controlled release of drugs. However, to ensure maximum efficiency of gold nanoparticles upon the drug release via the plasmon-enhanced photothermal effect, it is necessary to optimize their spectral parameters for operation in the human body that requires both theoretical research and development of appropriate methods for nanostructures fabrication. In this work, mathematical modeling of light extinction spectral dependences for gold nanostructures of different morphology was performed to determine their geometric parameters that provide the occurrence of localized surface plasmon resonance (LSPR) in the red and near infrared regions of the spectrum, where the transparency window of biological tissues exists. Based on the results of previous studies and computer modeling, using hollow gold nanoshells to construct smart nanocarriers was found to be most reasonable. A protocol for production of these nanoparticles based on “silver-gold” galvanic replacement reaction, which is accompanied by a controlled shift of the LSPR wavelength position, was proposed and described in detail. It is shown that the loading of model biomolecules in hollow gold nanoshells significantly changes the output optical parameters of the system under investigation, which should be taken into account for matching with the laser excitation wavelength during the development of smart nanocarriers