Abstract
The gold nanoparticles (AuNPs) aggregation-induced colorimetric aptamer sensing platform is commonly employed in bioassays. However, it has certain limitations, such as the requirement of instruments like a spectrophotometer for accurate quantitative readout and the background color interference. In this work, a dual-mode photothermal (PT) and smartphone colorimetric aptamer sensing platform was developed for tobramycin (TOB) assay using a digital thermometer or smartphone. Single-standard DNA (ssDNA) was utilized to bind the surface of AuNPs and maintain the dispersion of AuNPs at high salt concentrations. After the addition of the TOB, aptamer will specifically bind with it and separate from the gold surface. Then the aggregation of AuNPs can be observed in salt conditions, accompanying the AuNPs solution color change (red–purple-blue) and enhancing the PT effect. The DNA structural influence was carefully investigated. Under optimum conditions, the TOB assay by PT and RGB colorimetric mode have the limits of detection (LODs) of 1.7 μM and 1.3 μM, respectively. Furthermore, it is well demonstrated by the determination of TOB in food samples, offering high selectivity and sensitivity. It has potential for future application in point-of-care testing (POCT) with the benefits of inexpensive, easy to operate, and high specificity.
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