title: Polyvinylpyrrolidone molecular weight controls silica shell thickness on Au nanoparticles with diglycerylsilane as precursor.
abstract: Several strategies have been described for the preparation of silica-encapsulated gold nanoparticles (SiO(2)-AuNP), which typically suffer from an initial interface between gold and silica that is difficult to control, and layer thicknesses that are very sensitive to minor changes in silane concentration and incubation time. The silica shell thicknesses are normally equal to or larger than the gold particles themselves, which is disadvantageous when the particles are to be used for biodiagnostic applications. We present a facile and reproducible method to produce very thin silica shells (3-5 nm) on gold nanoparticles: the process is highly tolerant to changes in reaction conditions. The method utilized polyvinylpyrrolidone (PVP) of specific molecular weights to form the interface between gold and silica. The method further requires a nontraditional silica precursor, diglycerylsilane, which efficiently undergoes sol-gel processing at neutrality. Under these conditions, higher molecular weight PVP leads to thicker silica shells: PVP acts as the locus for silica growth into an interpenetrating organic-inorganic hybrid structure.
authors: Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1.
authors: Alan
authors: A
authors: Vanderkooy
authors: Michael A
authors: MA
authors: Brook
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D002951:Citrates / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008956:Models, Chemical; D008970:Molecular Weight; D036103:Nanotechnology / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry; D044367:Phase Transition; D011108:Polymers / Q000737:chemistry; D011205:Povidone / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D002951:Citrates; D009930:Organic Chemicals; D011108:Polymers; D012821:Silanes; D006046:Gold; D012822:Silicon Dioxide; D011205:Povidone