Refreshing DNA-Based Nanoprobes by Alcohol for Heavy Metal Detection: Toward Sustainable Sensing Nanomaterials

Abstract

Increasing the applications of disposable nanomaterials yet with potential environmental risk and the resulting nanowastes have become a problem of public concern worldwide. However, efficient recovery of useful materials from nanowastes is currently limited by their tiny size, high physicochemical activity, and unpredictable aggregation. We have developed a conceptually new strategy for recycling nanoprobes by alcoholic solvent “refreshing”. In specific, DNA-functionalized gold nanoparticles and nanorods are employed as colorimetric nanoprobes for Hg(II) and Ag(I) ions, respectively, both of which rely upon target-induced DNA terminal base pairing and the subsequent base pair stacking assembly of the nanoprobes. Upon the introduction of isopropanol to the “waste” aggregates, however, the DNAs are denaturalized to release heavy metal ions, leading to restoration of individual nanoprobes. The fine modulation of DNA hybridization not only affords sensitive detection but also addresses the recycling of the nanoprobes with high efficiency (>80%) while preserving the detection performance irrespective of the nanoprobe shape and surface-grafted DNA sequence. We further demonstrate the use of the recycled nanoprobes in the detection of Hg(II) species from salmon muscle tissue. With the generality of the recovering method and the combined features of the renewable nanoprobes, including high recycling efficiency and retained functionality, sustainable sensing nanomaterials are within reach.

Naked-Eye LAMP Assay of M. tuberculosis in Sputum by In Situ Au Nanoprobe Identification: For the In Vitro Diagnostics of Tuberculosis

“…Although colorimetric detection through magnesium pyrophosphate-induced turbidity change has gained popularity, the formation of the white precipitate may cause interference with the LAMP reaction . In the past few years, gold nanoparticles (AuNPs) with strong plasmon resonance and high extinction coefficient have gained popularity as a colorimetric indicator for recognition events, , which showcase the potential to substitute fluorescent dyes in LAMP assays. Indeed, it has been reported that the interaction of AuNPs with ssDNA primers and Bst DNA polymerase can boost the specificity of amplification in LAMP reactions .…”