title: Multivalent linkers for improved covalent binding of oligonucleotides to dye-doped silica nanoparticles.
abstract: This paper describes the fabrication of oligonucleotide-coated Cy5-doped silica nanoparticles using a combination of multivalent linkers and their use in surface-based DNA sandwich hybridization assays. Dipodal silane is introduced as a means to fabricate amine-coated silica nanoparticles and its advantages compared to monopodal silanes are discussed. The use of dipodal silane in conjunction with three different polymer linkers (oxidized dextran, linear and 8-arm polyethylene glycol (PEG)) to immobilize single-stranded DNA to Cy5-doped nanoparticles is investigated and dynamic light scattering measurements and Fourier transform infrared spectroscopy are used to follow the progression of the functionalization of the nanoparticles. We observe a significant improvement in the binding stability of the single-stranded DNA when the dipodal silane and 8-arm PEG are used in combination, when compared to alternative conjugation strategies. Both 8mer and 22mer oligonucleotides are securely conjugated to the high-brightness nanoparticles and their availability to hybridize with a complementary strand is confirmed using solution-based DNA hybridization experiments. In addition, a full surface-based sandwich assay demonstrates the potential these nanoparticles have in the detection of less than 500 femtomolar of a DNA analogue of micro RNA, miR-451.
authors: Biomedical Diagnostics Institute, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors: S M
authors: SM
authors: Kelleher
authors: R I
authors: RI
authors: Nooney
authors: S P
authors: SP
authors: Flynn
authors: E
authors: E
authors: Clancy
authors: M
authors: M
authors: Burke
authors: S
authors: S
authors: Daly
authors: T J
authors: TJ
authors: Smith
authors: S
authors: S
authors: Daniels
authors: C
authors: C
authors: McDonagh
mesh_terms: D000588:Amines / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D000067493:Dynamic Light Scattering; D053758:Nanoparticles / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry* / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000588:Amines; D004277:DNA, Single-Stranded; D009841:Oligonucleotides; D012821:Silanes; D011092:Polyethylene Glycols; D012822:Silicon Dioxide