Smartphone-assisted colorimetric biosensor for on-site detection of Cr3+ ion analysis

A simple and low-cost biosensor has been established for the detection of Cr3+ ion by using the image processing function of the smartphone. In the presence of Cr3+ ion, its dependent DNAzyme can spe-cifically cleave the substrate strand, resulting in the release of ligation probe, which will trigger hyper-branched rolling circle amplification (HRCA) to produce hydrogen ions, causing the color change of the solution containing cresol red. A free APP named Pixel Picker has been further used to measure the RGB values. It can be well found that the R/G values correlate with Cr3+ ion concentrations with a linear detection range of 0.5 mu M-50 0 mu M and a lowest detection limit of 0.12 mu M. In addition, the proposed biosensor has been successfully applied to determine Cr3+ ions in various milks. In a word, the con-structed smartphone-assisted colorimetric biosensor has the advantages of simplicity, low cost, high specificity and anti-interference ability. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A simple and low-cost biosensor has been developed for the detection of Cr3+ ion using the image processing function of a smartphone. The biosensor shows simplicity, affordability, high specificity, and anti-interference ability.