A novel colorimetric assay for calcium ion and calmodulin detection based on gold nanoparticles

Abstract

A facile and reliable colorimetric method for detection of calcium ion and calmodulin was developed, which is based on the calcium ion-induced aggregation of gold nanoparticles, accompanied by an obvious color change from red to blue-purple. Calcium ion can be detected in the concentration range from 2.5 to 37.5 µmol·L⁻¹ with a 0.6 µmol·L⁻¹ detection limit. Calmodulin can preferentially capture calcium ion to inhibit the aggregation and the color changes of gold nanoparticles, and can be determined with a 0.8 µg·mL⁻¹ detection limit over the concentration range from 0 to 33.6 µg·mL⁻¹.

Keywords:

• Gold nanoparticles
• Calcium ion
• Calmodulin
• Colorimetric