Fabrication of DNA–magnetite hybrid nanofibers for water detoxification Daminda Navarathne a , Yogesh Ner a,1 , Menka Jain b , James G. Grote c , Gregory A. Sotzing a, ⁎ a Department of Chemistry and the Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136, USA b Department of Physics, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136, USA c US Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXPS, Wright-Patterson Air Force Base, OH 45433-7707, USA abstract article info Article history: Received 27 July 2010 Accepted 9 September 2010 Available online 17 September 2010 Keywords: Nanofibers Magnetic materials Nanomaterials Hybrid materials Water detoxification DNA–magnetite hybrid nanofibers were fabricated by electrospinning a spin dope consisting of oleic acid coated magnetite nanoparticles and DNA–CTMA in ethanol/chloroform mixed solvent. The fabricated nanofibers exhibit superparamagnetic behaviour owing to embedded magnetite nanoparticles. It is demonstrated that these nanofibers can be used as effective detoxification materials in aqueous media as a combined result of DNA's affinity to both organic and inorganic toxicants, high surface area of the nanofibers and the fast and easy separation due to magnetite nanoparticles under external magnetic field. In addition to detoxification, these novel hybrid nanofibers have potential applications in many technological areas such as catalysis and drug delivery. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The integration of biomaterials with inorganic materials repre- sents a new class of hybrid composites wherein functionalities of both components can be used synergistically to achieve unique physical and chemical properties [1–3]. Furthermore, nanofibers made from these materials would accelerate their use in many applications where high surface area and high aspect ratio are of key importance. Nanofibers made with bio-functional materials have demonstrated their unique role in many technological applications [4–6]. The next advance in the field would be the fabrication of high surface area composite materials with multiple functionalities. Recently, we have shown that electrospinning, a simple, scalable and versatile tech- nique, can be used to fabricate high surface area nanofibers from surface modified DNA [7,8]. It is hypothesized that DNA–magnetite hybrid (M–DNA) nanofibers can be constructed by incorporating magnetite nanoparticles (MNPs), with utility in many applications such as drug delivery, catalysis and environmental cleanup. Herein, we report the fabrication of M–DNA nanofibers and demonstrate their applicability for water detoxification. In addition to water pollutants from conventional sources, traces of pharmaceuticals and personal care products have been found in the water supply [9]. These mainly drug-based contaminants have gained tremendous attention as potential pollutants. Thus, materials with an affinity for both organic and inorganic toxicants have a unique role in waste treatment. In this sense, DNA represents an efficient decon- tamination material due to its higher affinity for organic and inorganic toxicants [10–13]. However, the water solubility of DNA remains a major concern for its use as a decontaminant in aqueous media. Various approaches have been developed to construct water insoluble decontamination materials from DNA, including use of DNA com- plexes [11], silane coupling agents [12], and UV crosslinking [13]. In order to utilize DNA in this manner, high surface area would be beneficial. High surface area nanofibers have already been commer- cially adopted by the filtration industry [14]. Incorporating magnetic nanoparticles into nanofibers renders easy, fast and efficient separa- tion under an external magnetic field as compared to filtration or centrifugation. Combining DNA's binding ability to both organic and inorganic toxicants with high surface area nanofibers and the use of magnetic nanoparticles for separation results in an efficient detoxi- fication material. 2. Materials and methods 2.1. Preparation of DNA–CTMA complex The DNA–CTMA complex was prepared using 1% (w/w) aqueous solutions of 500 kDa salmon DNA (a kind donation from CIST-Japan) and cetyltrimethylammonium (CTMA) bromide (Sigma, 99%) accord- ing to a reported procedure [7]. A solution of Na DNA was added to a CTMA bromide solution to form a 1:1 stoichiometric mixture which led to the formation of the precipitate of the DNA–CTMA complex. This was filtered and washed with water and dried overnight in a vacuum oven at 40 °C. Materials Letters 65 (2011) 219–221 ⁎ Corresponding author. Tel.: + 1 860 486 4619; fax: + 1 860 486 4745. E-mail address: sotzing@mail.ims.uconn.edu (G.A. Sotzing). 1 Present address: Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA. 0167-577X/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2010.09.033 Contents lists available at ScienceDirect Materials Letters journal homepage: www.elsevier.com/locate/matlet