A close analysis of metal-enhanced fluorescence of tryptophan induced by silver nanoparticles: wavelength emission dependence

Abstract

In the last few years, silver nanoparticles have been proposed as a promising alternative for the label-free detection of proteins via metal-enhanced fluorescence. Generally, the aromatic amino acid tryptophan is most frequently used in this type of studies, because the intrinsic fluorescence of proteins is usually dominated by tryptophan emissions. In the present study, we evaluated the fluorescence behavior of tryptophan in the presence of a silver colloid with nanoparticles of 100 nm in diameter. The results showed that a nanoparticles concentration of 32 mg L−1 induced maximum fluorescence enhancement. However, the metal-enhanced fluorescence was dependent on the emission wavelength of tryptophan, and this phenomenon was closely related to the metal surface reabsorption process (inner filter effect), suggesting that the plasmon resonance reabsorption effect should be taken into account in analyses involving protein studies by metal-enhanced fluorescence.

Alanyl glycoconjugate: a selective receptor for free and protein-bound tryptophan

“…The interactions between L-N2O2 and Trp were further investigated using fluorescence spectroscopy, as the emission intensity resulting from the indole group of the latter gets either enhanced [9][10][11] or quenched 12,13 by the receptor molecule. When a methanolic solution of L-N2O2 was added to the aqueous solution of Trp, quenching of the latter's fluorescence intensity band at 355 nm was noticed.…”

Synthesis Optimisation of Lysozyme Monolayer‐Coated Silver Nanoparticles in Aqueous Solution

“…During the past few decades, many researchers [1] from various fields of science have been involved in the synthesis of noble metal nanoparticles for physics, chemistry, biology, and medicine applications [2]. This occurred because of the unique physicochemical properties of such materials, which make it possible to solve a wide range of problems in medicine, biology, catalysis, optics, and so forth [3][4][5][6][7][8][9].…”