A new label-free method for the detection of apoptosis was proposed based on colorimetric assay of caspase-3 activity using an unlabeled Asp-Glu-Val-Asp (DEVD)-containing peptide substrate and unmodified gold nanoparticles (AuNPs).

Through the silver ion catalysis to form colored KMnO4, and combined with the DNA hybridization chain reaction and silver nanowire for signal amplification, a highly sensitive and selective colorimetric sensor has been developed for the detection of Hg(2+).

In this communication, we demonstrate our recent finding that iron-substituted SBA-15 (Fe-SBA-15) microparticles possess intrinsic peroxidase-like activity and can catalyze the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H(2)O(2) to develop a blue color in aqueous solution, leading to a simple approach towards colorimetric detection of H(2)O(2) with a linear detect...

Oratile Semong and Bareki Shima Batlokwa The monitoring of thiocyanate (SCN−) in food is consumer health safety relevance. In this work, a colorimetric method for the detection SCN− milk using silver nanoparticles (AgNPs) nanozyme presented.

We present a novel reflectance-based colorimetric aptasensor using gold nanoparticles for the detection of oxytetracycline for the first time. It was found that the reflectance-based measurement at two wavelengths (650 and 520 nm) can generate more stable and sensitive signals than absorbance-based sensors to determine the aggregation of AuNPs, even at high AuNP concentrations. One of the most ...

We describe applications of a colorimetric assay based on supramolecular assemblies of lipid-polydiacetylene vesicles for analysis and screening of membrane interactions of lipophilic enzymes, peptides, and ions and for study of the effects of lipid composition upon membrane properties. The lipid-polymer aggregates undergo visible and quantifiable blue-to-red transitions following interfacial i...

Herein, we report a phenylboronic acid functionalized gold nanoparticle (GNP)-based colorimetric assay for rapid detection of Staphylococcus aureus (S. aureus) with high sensitivity. In this approach, GNPs can bind to S. aureus by the reaction of phenylboronic acid with the cis-diol configuration in glycans on the bacterial surface, providing a colorimetric readout of the binding event. Using t...