Naked-eye visualization of nucleic acid amplicons using hierarchical nanoassembly

Abstract

This study reports the development of a rapid visualization method for DNA amplicons. Oligonucleotide-coated gold nanoparticles hierarchically assemble on DNA networks to form globular nanostructures, which precipitate into a distinct...

A rapid LAMP assay for the diagnosis of oak wilt with the naked eye

“…Both healthy and B. fagacearum infected red oak samples were tested using the designed LAMP assay and their uorescence intensities were measured. To enable a faster identi cation of target ampli cation a rapid optical detection was employed with laboratory synthesized nanoparticles [12]. The nal appearance of the solution was used to distinguish between positive (red pellet) and negative samples (uniform pink supernatant).…”

“…However, without a turbidimeter, distinguishing positive and negative samples with the naked eye was di cult, especially when the sample size is as small as 25 µL. Therefore, to improve the detection of this turbidity with the naked eye, a newly developed method involving hierarchical gold nanoparticle assembly was employed here [12]. The addition of AuNP-oligos gave the amplicons solution a pink color, which upon precipitation using NaCl and alcohol resulted in a red pellet in the sample tube while the remaining solution was clear.…”

“…The method was then optimized for cost-effective and "point of care" (i.e., eld) use based on results of beta testing by multiple potential users. Research by others has yielded preliminary or potential techniques for rapid DNA assay of sapwood samples in the eld [9,10,11,12]. Nucleic acid ampli cation tests (NAATs), such as PCR-based assays, have been considered as one of the most sensitive methods for pathogen detection due to their ability to amplify very small amounts of the pathogen's genetic material [13,14].…”

“…In this study, we report the development, characterization, and testing of the rst LAMP assay for rapid and sensitive detection of Bretziella fagacearum, the causal agent of oak wilt, in Quercus rubra (northern red oak) samples. Furthermore, the coupling of our LAMP assay with a recently developed amplicon visualization technique employing nanoparticle assembly [12] enables nakedeye detection of the oak wilt fungus.…”