Taking a Hard Line with Biotemplating: Cobalt-Doped Magnetite Magnetic Nanoparticle Arrays

Scott M. Bird, Johanna Galloway, andrea rawlings, jonathan bramble, sarah staniland

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Rapid advancements made in technology, and the drive towards miniaturisation, means that we require reliable, sustainable and cost effective methods of manufacturing a wide range of nanomaterials. In this bioinspired study, we take advantage of millions of years of evolution, and adapt a biomineralisation protein for surface patterning of biotemplated magnetic nanoparticles (MNPs). We employ soft-lithographic micro-contact printing to pattern a recombinant version of the biomineralisation protein Mms6 (derived from the magnetotactic bacterium Magnetospirillum magneticum AMB-1). The Mms6 attaches to gold surfaces via a cysteine residue introduced into the N-terminal region. The surface bound protein biotemplates highly uniform MNPs of magnetite onto patterned surfaces during an aqueous mineralisation reaction (with a mean diameter of 90+/-15 nm). The simple addition of 6% cobalt to the mineralisation reaction maintains the uniformity in grain size (with a mean diameter of 84+/-14 nm), and results in the production of MNPs with a much higher coercivity (increased from [approximate]156 Oe to [approximate]377 Oe). Biotemplating magnetic nanoparticles on patterned surfaces could form a novel, environmentally friendly route for the production of bit-patterned media, potentially the next generation of ultra-high density magnetic data storage devices. This is a simple method to fine-tune the magnetic hardness of the surface biotemplated MNPs, and could easily be adapted to biotemplate a wide range of different nanomaterials on surfaces to create a range of biologically templated devices.
Original languageEnglish
Pages (from-to)7340-7351
Number of pages12
JournalNanoscale
Volume7
Issue number16
Early online date23 Mar 2015
DOIs
Publication statusPublished - 28 Apr 2015

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