Plasmon-enhanced fluorescence of labeled biomolecules on top of a silver sol-gel film

Abstract

A simple chemical technique was devised for the fabrication of silver nanostructured substrates which can be used for plasmonic enhancement of labeled proteins fluorescence. For bovine serum albumin labeled with fluorescein isothiocyanate, the obtained enhancement factor ranges from three to seven, depending on metal-luminophore spacing and silver nanoparticle size. For excitation with linear polarized light, the enhancement factor increases noticeably for p-polarization and decreases for s-polarization. The experimental results were interpreted in terms of the theoretical model in which the enhancement factor depends on incident light polarization, luminophoremetal spacing and silver nanoparticle size. Proposed plasmonic substrates can be considered as an affordable replacement of standard ones in different types of fluorescent assays for the purpose of increasing sensitivity.

Colloidal Silver Films on Polypropylene and Polyethylene

“…But if just a single polyelectrolyte layer (of any salt concentration) was deposited prior to the silver layer, the optical density spectrum of the system showed a clear plasmon peak (Figure (a)–(c)). The spectra of the film on glass has the same shape as silver film on polypropylene with 3 PE layers (0.5 M salt concentration).…”

“…In the previous works the PE film formed on glass allowed depositing dense silver film thereon. To the best of the authors’ knowledge there is no study of the silver colloidal films formation on the non‐polar polymers surfaces modified only by deposited polyelectrolyte layers.…”

“…These films support formation of localized and extended plasmon‐polaritons upon optical excitation. From year to year conditions of the plasmonic films preparation are getting more advanced and include thermal vacuum deposition, lithography, etching, focused‐ion beam nanofabrication, and colloidal films . It allows tailoring the properties of films for desirable applications.…”

“…Chemical properties of the glass surface are well‐established, so the deposition of metal nanoparticles onto glass is more reproducibly reliable . Silanization of the glass substrate or predeposition of a polyelectrolyte (PE) layer are used for colloidal nanoparticle immobilization. The latter is an easy technique based on electrostatic interactions.…”

Colloidal Photoluminescent Refractive Index Nanosensor Using Plasmonic Effects

“…Lanthanides or transition metal ions in nanocrystals [22,23] may also become the advantageous probes. Refraction sensitive luminescent tips can be fabricated by means of colloidal crystals covered with noble metals [24] as well as by any other technique enabling cheap fabrication of nanostructured metal surface [25][26][27] with subsequent linkage of fluorescent probes via a dielectric spacer [28].…”