Modulation of DNA‐Modified Gold‐Nanoparticle Stability in Salt with Concatemeric Single‐Stranded DNAs for Colorimetric Bioassay Development

Golden island: Periodically assembled gold nanoparticles (AuNPs) on a long single‐stranded DNA (ssDNA) with a repetitive sequence, produced by rolling circle amplification (RCA), form island‐like, globular structures under salted conditions (see figure; green = short DNA probe, orange=AuNP, black=long ssDNA from RCA). The AuNPs in such islands retain their original red color whereas unassembled AuNPs form purple aggregates under the same conditions.