Flame-sprayed superparamagnetic bare and silica-coated maghemite nanoparticles: Synthesis, characterization, and protein adsorption-desorption

Dan Li, Wey Yang Teoh, Cordelia Selomulya, Robert C Woodward, Rose Amal, Bettina Rosche

Research output: Contribution to journalArticleResearchpeer-review

117 Citations (Scopus)


Superparamagnetic maghemite (gamma-Fe2O3) nanoparticles of tunable diameters and silica-coated maghemite (SiO2/gamma-Fe2O3) nanoparticles of controllable morphology were successfully synthesized using a one-step flame spray pyrolysis (FSP) technique. The physical, chemical, and magnetic properties of gamma-Fe2O3 and SiO2/gamma-Fe2O3 nanostructures were characterized and compared with those of silica-coated FSP gamma-Fe2O3 produced by a conventional sol-gel method. Bovine serum albumin (BSA) adsorption-desorption was investigated as a model to demonstrate the feasibility of synthesized superparamagnetic nanoparticles for bioadsorption and bioseparation. Protein adsorption was observed to follow the Langmuir isotherm, with the highest binding capacity of 348 mg of BSA/g of particle and a dissociation constant of 0.0159 g/L attainable for FSP gamma-Fe2O3 (d(XRD) = 14 nm) in 10 mM formate buffer. Electrostatically governed BSA orientations were proposed for different particle-buffer systems. Shifting the pH of suspension with K2HPO4 enabled effective recovery of adsorbed BSA.
Original languageEnglish
Pages (from-to)6403 - 6413
Number of pages11
JournalChemistry of Materials
Issue number26
Publication statusPublished - 2006

Cite this