title: Surface passivation improves the synthesis of highly stable and specific DNA-functionalized gold nanoparticles with variable DNA density.
abstract: We report a novel and multifaceted approach for the quick synthesis of highly stable single-stranded DNA (ssDNA) functionalized gold nanoparticles (AuNPs). The method is based on the combined effect of surface passivation by (1-mercaptoundec-11-yl)hexa(ethylene glycol) and low pH conditions, does not require any salt pretreatment or high excess of ssDNA, and can be generalized for oligonucleotides of any length or base sequence. The synthesized ssDNA-coated AuNPs conjugates are stable at salt concentrations as high as 3.0 M, and also functional and specific toward DNA-DNA hybridization, as shown from UV-vis spectrophotometry, scanning electron microscopy, gel electrophoresis, fluorescence, and small angle X-ray scattering based analyses. The method is highly flexible and shows an additional advantage of creating ssDNA-AuNP conjugates with a predefined number of ssDNA strands per particle. Its simplicity and tenability make it widely applicable to diverse biosensing applications involving ssDNA functionalized AuNPs.
authors.affiliation: †Elettra-Sincrotrone Trieste, s.s. 14 km 163.5 in Area Science Park, 34149 Basovizza, Trieste Italy.
authors.forename: Jashmini
authors.initials: J
authors.lastname: Deka
authors.affiliation: ‡Institute of Physical Engineering, Brno University of Technology, Technická 2, 61669 Brno, Czech Republic.
authors.forename: Rostislav
authors.initials: R
authors.lastname: Měch
authors.affiliation: †Elettra-Sincrotrone Trieste, s.s. 14 km 163.5 in Area Science Park, 34149 Basovizza, Trieste Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Ianeselli
authors.affiliation: §Institute for Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9/V, A-8010 Graz, Austria.
authors.forename: Heinz
authors.initials: H
authors.lastname: Amenitsch
authors.affiliation: §Institute for Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9/V, A-8010 Graz, Austria.|∥Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, OX11 0DE Didcot, United Kingdom.
authors.forename: Fernando
authors.initials: F
authors.lastname: Cacho-Nerin
authors.affiliation: ⊥INSTM - ST Unit, s.s. 14 km 163.5 in Area Science Park, 34149 Basovizza, Trieste Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Parisse
authors.affiliation: †Elettra-Sincrotrone Trieste, s.s. 14 km 163.5 in Area Science Park, 34149 Basovizza, Trieste Italy.|⊥INSTM - ST Unit, s.s. 14 km 163.5 in Area Science Park, 34149 Basovizza, Trieste Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Casalis
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics; D019855:Ethylene Glycol / Q000737:chemistry; D005453:Fluorescence; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics
chemical_list: D004277:DNA, Single-Stranded; D009841:Oligonucleotides; D006046:Gold; D019855:Ethylene Glycol
keywords: DNA functionalization; gold nanoparticles; oligo ethylene glycol; salt-stability; specificity; surface passivation; variable DNA density