30 research outputs found
Simple and Real-Time Colorimetric Assay for Glycosidases Activity Using Functionalized Gold Nanoparticles and Its Application for Inhibitor Screening
The development of real-time assays for enzymes has been
receiving
a great deal of attention in biomedical research recently. Self-immolative
elimination is the spontaneous and irreversible disassembly of a multicomponent
construct into its constituent fragments through a cascade of elimination
processes, in response to external stimuli. Here, we report a simple
and real-time colorimetric assay for glycosidases (β-galactosidase
and β-glucosidase). Self-immolative elimination was utilized
to release amines to give rise to aggregation and color change by
electrostatic attraction after cleavage of the trigger by enzymes
displayed on functionalized gold nanoparticles (Gal-Lip-AuNPs and
Glc-Lip-AuNPs, where AuNPs denotes gold nanoparticles). The detection
limits for β-galactosidase and β-glucosidase were as low
as 9.2 and 22.3 nM at 20 min, and they improved slightly over time.
Thus, glycosidase activity was detected successfully in real time,
and this technique could be used for glycosidase inhibitor screening,
based on real-time colorimetric variation
Dual Reaction-Based Multimodal Assay for Dopamine with High Sensitivity and Selectivity Using Functionalized Gold Nanoparticles
A simple and dual chemical reaction-based
multimodal assay for dopamine with high sensitivity and selectivity
using two types of functionalized gold nanoparticles (FB-AuNPs/NsNHS-AuNPs),
i.e. fluorescein modified gold nanoparticles (FB-AuNPs) and Nile blue
modified gold nanoparticles (NsNHS-AuNPs), was successfully fabricated.
This assay for dopamine presents colorimetric visualization and double
channel fluorescence enhancement at 515 and 665 nm. The absorbance
and fluorescence changes were linearly proportional to the amounts
of dopamine in the range of nanomolar scale (5–100 nM). The
detection limits for absorbance and fluorescence were as low as 1.2
nM and 2.9 nM (S/N = 3), respectively. Furthermore, the extent application
of this multimodal assay has been successfully demonstrated in human
urine samples with high reliability and applicability, showing remarkable
promise in diagnostic purposes
Particle size and dispersibility of the aqueous dispersions containing 4.0% (w/w) avermectin with different surfactant contents.
<p>Different letters indicate significant differences according to Duncan’s multiple range test at P < 0.05.</p
XRD patterns of pure components in the nano-formulation and lambda-cyhalothrin solid nanodispersion.
<p>SDS: 1-dodecanesulfonic acid sodium salt; MRES: maleic rosin-polyoxypropylene-polyoxyethylene ether sulfonate.</p
Particle size and dispersibility of the aqueous dispersions containing 4.0% (w/w) avermectin with different surfactant contents.
<p>Different letters indicate significant differences according to Duncan’s multiple range test at P < 0.05.</p
Stability of the lambda-cyhalothrin solid nanodispersion for (a) different storage times and (b) different storage temperatures.
<p>PDI: polydispersity index.</p
SEM photograph of lambda-cyhalothrin nanoparticles.
<p>SEM photograph of lambda-cyhalothrin nanoparticles.</p
Photolysis of avermectin in the solid nanodispersion and technical material.
<p>Photolysis of avermectin in the solid nanodispersion and technical material.</p
Stability of the avermectin solid nanodispersion at 25°C.
<p>Different letters indicate significant differences according to Duncan’s multiple range test at P < 0.05.</p
Effect of composite surfactants on the particle size and dispersibility of the avermectin aqueous dispersions.
<p>Effect of composite surfactants on the particle size and dispersibility of the avermectin aqueous dispersions.</p