title: Control of metal nanoparticles aggregation and dispersion by PNA and PNA-DNA complexes, and its application for colorimetric DNA detection.
abstract: We have demonstrated that mixed-base PNA oligomers are effective coagulants of citrate ion-coated gold and silver nanoparticles (AuNPs and AgNPs), and PNA-induced particle aggregation can be disrupted by hybridization of PNA with a specific DNA. Using particles' aggregation/dispersion as a measure, we have investigated how PNA and PNA-DNA complexes bind to AuNPs and AgNPs and modulate particles' stability differently relative to their DNA counterparts. We have made the following original discoveries: (1) mix-base PNA oligomers can induce immediate particle aggregation in a concentration- and chain-length-dependent manner; (2) PNA oligomers have a higher affinity to AuNPs and AgNPs than its ssDNA counterpart; (3) PNA-DNA complexes, although having a stable double helix structure similar to dsDNA, can effectively protect the particles from salt induced aggregation, and the protection effect of different nucleic acids are in the order of PNA-DNA complex > ssDNA > dsDNA; (4) all the characteristics are identical for AuNPs and AgNPs; and (5) AgNPs is more sensitive in response to destabilization effect and is proven a more sensitive platform for colorimetric assays. The control of particle aggregation and dispersion by PNA and PNA-DNA complexes has been used to detect a specific DNA sequence with single-base-mismatch resolution. zeta potential measurements have been conducted to reveal how distinct backbone properties of PNA and PNA-DNA complexes relative to their DNA counterparts contribute to the distinct binding characteristics.
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602. xd-su@imre.a-star.edu.sg
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Su
authors.forename: Roejarek
authors.initials: R
authors.lastname: Kanjanawarut
mesh_terms: D020137:Base Pair Mismatch; D003124:Colorimetry; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D020135:Peptide Nucleic Acids / Q000378:metabolism*
chemical_list: D004277:DNA, Single-Stranded; D020135:Peptide Nucleic Acids; D004247:DNA