Large-scale production and characterisation of biocompatible colloidal nano-alumina
Wan Aizuddin bin W Razali , Varun K. A. Sreenivasan , Ewa M. Goldys , and Andrei V Zvyagin
Abstract: Rapid uptake of nanomaterials in Life Sciences calls for the development of universal, high-yield techniques for their production and interfacing with biomolecules. Top-down methods take advantage of the existing variety of bulk and thin film solid-state materials for improved prediction and control of the resultant nanomaterial properties. We demonstrate the power of this approach using high-energy ball milling (HEBM) of alumina (Al2O3). Nano-alumina particles of the mean size 25 nm in its most stable α-crystallographic phase were produced in gram quantities, suitable for biological and biomedical applications. Nanomaterial contamination from zirconia balls used in HEBM was reduced from 19% to 2% using a selective acid etching procedure. The biocompatibility of the milled nanomaterial was demonstrated by forming stable colloids in water and physiological buffers, corroborated by zeta potentials of +40 mV and -40 mV, and characterized by in vitro cytotoxicity assays. Finally, the feasibility of milled nano-alumina surface to anchor a host of functional groups and biomolecules was demonstrated by functionalisation of their surface using a facile silane chemistry, resulting in decoration of the nanoparticle surface with amino groups suitable for further conjugation of biomolecules.
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