A Portable Smart-Phone Readout Device for the Detection of Mercury Contamination Based on an Aptamer-Assay Nanosensor

Abstract

The detection of environmental mercury (Hg) contamination requires complex and expensive instruments and professional technicians. We present a simple, sensitive, and portable Hg2+ detection system based on a smartphone and colorimetric aptamer nanosensor. A smartphone equipped with a light meter app was used to detect, record, and process signals from a smartphone-based microwell reader (MR S-phone), which is composed of a simple light source and a miniaturized assay platform. The colorimetric readout of the aptamer nanosensor is based on a specific interaction between the selected aptamer and Hg2+, which leads to a color change in the reaction solution due to an aggregation of gold nanoparticles (AuNPs). The MR S-phone-based AuNPs-aptamer colorimetric sensor system could reliably detect Hg2+ in both tap water and Pearl River water samples and produced a linear colorimetric readout of Hg2+ concentration in the range of 1 ng/mL–32 ng/mL with a correlation of 0.991, and a limit of detection (LOD) of 0.28 ng/mL for Hg2+. The detection could be quickly completed in only 20 min. Our novel mercury detection assay is simple, rapid, and sensitive, and it provides new strategies for the on-site detection of mercury contamination in any environment.

A simple and compact smartphone-based device for the quantitative readout of colloidal gold lateral flow immunoassay strips

“…To this end, the ambient light sensor on a given smartphone is sensitive and accurate and offers a more consistent starting point to develop a biosensor readout system. A microplate reader based on smartphone's ambient light sensor to measures transmitted light intensities of liquid assay have been developed in our laboratory [33][34][35][36]. The results were consistent with those obtained from a professional microplate reader and demonstrated its potential use in a variety of detection strategies for different targets.…”

Highly Sensitive and Selective Colorimetric Detection of Methylmercury Based on DNA Functionalized Gold Nanoparticles

“…To overcome the limitation of the above methods, recently, nanomaterial-based assays have been widely used for developing rapid and cost-effective methods for the detection of various heavy metal ions in environmental and biological samples [ 7 , 8 , 9 ]. Due to the strong metallophilic interactions between Hg 2+ and some other metallic atoms, such as gold and silver, numerous metallic nanoparticle-based assays for Hg 2+ have been developed [ 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. However, there are fewer nanomaterial-based assays for CH 3 Hg + compared to Hg 2+ ions [ 17 , 18 , 19 ], which is probably due to the weak interactions between CH 3 Hg + and metal nanomaterials.…”

A review of smartphone point‐of‐care adapter design

“…The adapter is connected to the smartphone, and the group developed a custom algorithm for image processing and acquisition. As depicted in Figure D, Xiao et al developed a smartphone adapter as an aptamer‐assay nanosensor for mercury contamination detection and readout. The adapter consists of a switch, resistance, a battery, an LED, a microwell, a sample holder, an ambient light sensor and a plastic body.…”

“…Biochemical applications of smartphone adapter (A) by Lee et al, adopted with permission from Elsevier Publishing; (B) by Michelini et al, adopted with permission from Elsevier Publishing; (C) by Ming et al, © copyright 2015, American Chemical Society; (D) by Xiao et al, under the Creative Commons license; (E) by Wang et al, adopted with permission from the Royal Society of Chemistry; (F) by Wang et al, adopted with permission from Elsevier Publishing; (G) by Yang et al, adopted with permission from Elsevier Publishing; (H) by Zangheri et al, adopted with permission from Elsevier Publishing; and (I) by Zhang et al, adopted with permission from Elsevier Publishing…”