Coumarin-modified gold nanoprobes for the sensitive detection of caspase-3

Abstract

A coumarin-functionalized gold nanosensor connected to polypeptide chains was developed for the sensitive detection of caspase-3 based on a FRET process.

Self-Assembled Glycobis(acrylamide)-Stabilized Gold Nanoparticles for Fluorescent Turn-on Sensing of Lectin and Escherichia coli

“…Upon the addition of Con A (200 nM), Glc-bis particles in the Glc-bis@ AuNPs system bind strongly and selectively to Con A, leading to separation of the fluorophore (Glc-bis) from the surface of AuNPs. 26 This state turns the fluoroscence "on", which increases the average lifetime to 2.13 ns. Almost 61% of the quenched emission was recovered by the interaction of Glc-bis with Con A, which is consistent with the observations from steady-state measurments.…”

“…Hence, AuNPs find applications in fluorescence turn-on and turn-off probes. 26 Carbohydrate functionalization/stabilization of AuNPs makes them multivalent systems, thus facilitating their interactions with proteins like lectins. 27 There are different pathways to produce poly(acrylamide) composites with AuNPs (i) by polymerizing acrylamide along with a crosslinker and then synthesizing AuNPs 28 or (ii) by reacting HAuCl 4 with poly(acrylamide) under basic pH.…”

Coumarin as a structural component of substrates and probes for serine and cysteine proteases

“…Preventing this twisting process increases the quantum yield and restores fluorescence in aqueous media, as can be achieved through rigidization of the amino group in one or two rings [11,26]. In coumarin 343 (8), longer wavelengths of excitation (440 nm) and emission (480 nm, in aqueous solution) appear [27]. The extension of the π-electron system due to coupling in position 3 with a heteroaryl substituent and sulfonation at position 6 resulted in a bathochromic shift, high quantum yield and good water solubility of the resulting dye 9 with an absorption maximum of 426 nm and an emission maximum of 481 nm (in aqueous solution) [10].…”

Peptide-fluorophore/AuNP conjugate-based two-photon excited fluorescent nanosensor for caspase-3 activity imaging assay in living cells and tissue

“…Usually, homogeneous assay methods include colorimetric assays, 6 fluorescence polarization or fluorescence correlation spectroscopy-based assays, 7,8 and luminescence-based detection. [9][10][11][12][13] Meanwhile, inhomogeneous assay methods include Western blot assays, 14 atomic force microscopy-based assays, 15 and electrochemical detection. 16 Among these developed technologies, fluorescence resonance energy transfer (FRET)-based homogeneous detection 11,12 has taken a crucial place due to the excellent properties of fluorescence detection, such as high sensitivity, specificity, fast response, and technical simplicity.…”

“…[9][10][11][12][13] Meanwhile, inhomogeneous assay methods include Western blot assays, 14 atomic force microscopy-based assays, 15 and electrochemical detection. 16 Among these developed technologies, fluorescence resonance energy transfer (FRET)-based homogeneous detection 11,12 has taken a crucial place due to the excellent properties of fluorescence detection, such as high sensitivity, specificity, fast response, and technical simplicity. However, among the dyes acknowledged as energy donors, almost all were single-photon fluorescent dyes, resulting in limitation of their application under complicated biological conditions.…”