title: Hollow spherical nanoparticulate aggregates as potential ultrasound contrast agent: shell thickness characterization.
abstract: OBJECTIVE
  The objective of this work is to manufacture hollow spherical nanoparticulate aggregates for use as an ultrasound contrast agent by means of spray drying of nanoparticulate suspension at a fast drying rate.
  
  
  METHODS
  Biocompatible PMMA-MeOPEGMA and silica nanoparticles are used as the model nanoparticles. The impacts of changing the nanoparticle concentration, pH, and spray drying operating condition on the size and shell thickness-to-particle radius (S/R) ratio, which governs the shell mechanical stability, are investigated.
  
  
  CONCLUSIONS
  The results indicate that the hollow microspheres size varies between 2 and 10 mum having S/R ratio between 2% and 4%, where the smaller size particles exhibit a higher S/R ratio. The resultant S/R ratio is found to be more influenced by process parameters acting at the nanoparticle scale (e.g., suspension pH) than by the spray drying operating condition.
authors: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore. kunnong@ntu.edu.sg
authors: Kunn
authors: K
authors: Hadinoto
authors: Wean Sin
authors: WS
authors: Cheow
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D003287:Contrast Media / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry; D053758:Nanoparticles; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D008689:Methacrylates; C456562:methoxy polyethylene glycol methacrylate; D011092:Polyethylene Glycols; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate