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Abstract
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DNA molecules have a polymer language with four alphabets that can be designed with an arbitrary sequence, programmed base by base.[1] Rather than directing biological processes, synthetic forms of DNA are now utilized to program the assembly of nanoparticles. Spherical nucleic acids (SNAs) are an emerging class of three-dimensional nanostructures typically made by arranging linear nucleic acids at high density around a nanoparticle core. [2,3] Programmable assembly of SNAs is a target-responsive and sequence-specific molecular recognition event. In cases where SNAs are composed of gold nanoparticles (called AuNP-core SNAs), the programmable assembly events lead to generating naked-eye-observable colorimetric responses. The last two decades have seen a growing trend toward developing AuNP-core SNAs as medical diagnostic probes. This study provides greater insight into the utilization of DNA-programmable assembly of gold nanoparticles as a colorimetric transduction event for molecular diagnosis. Recently, we developed several strategies based on the target-responsive assembly of AuNP-core SNAs for the “naked-eye” colorimetric detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. [4-6] Conventional polymerase chain reaction (PCR), which requires minimal laboratory equipment (a simple thermal cycler), was modified for molecular diagnosis via the 5′-exonuclease activity of the DNA polymerase. Due to public health interest in the management of infectious diseases using simple, accessible, and affordable laboratory equipment, the DNA-based programmable assembly strategies have a valuable potential to design biosensors for point-of-care testing.
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