Cellular Nanomedicine Biocompatible nanofiber scaffolds on metal for controlled release and cell colonization Wenjun Dong, PhD, a Tierui Zhang, PhD, a Michelle McDonald, BSc, a Carmen Padilla, BSc, b Joshua Epstein, DSc, c Z. Ryan Tian, PhD a,b,d, 4 a Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas, USA b Department of Cell and Molecular Biology, University of Arkansas, Fayetteville, Arkansas, USA c Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA d Department of Microelectronics and Photonics, University of Arkansas, Fayetteville, Arkansas, USA Received 29 August 2006; accepted 18 October 2006 Abstract This paper reports for the first time a preparation of biocompatible titanate nanofiber scaffolds on the surface of titanium foil/mesh via a one-step hydrothermal reaction. The length and diameter of the nanofibers can be controlled by varying the fabrication parameters, such as reaction temperature, precursor concentration, and reaction time. The nanofibers can self-organize into macroporous (mostly 0.5À10 lm in diameter) scaffolds potentially useful for developing new bioscaffolds, photocatalysts, sensors, and drug delivery vehicles. Published by Elsevier Inc. Key words: Biocompatible; Nanofiber scaffolds; Controlled release; Cell colonization Since the discovery of carbon nanotubes in 1991 [1] there has been an increasing demand for developing new one-dimensional (1D) nanomaterials because of the novel application potentials associated with the anisotropic 1D nanostructures. It is believed that these 1D nanomaterials, especially the nanowires (NWs) and/or nanotubes (NTs) [2-8] with controlled morphology and spatial organization, would interact with biological entities (e.g. DNA, protein, cell) specifically. The TiO 2 -based NWs/NTs, for instance, have been found to be of technological importance in numerous applications including photovoltaic cells, photo- assisted water splitting, high-temperature catalysis, sensing, and functional bionanomaterials [9-11]. Several groups have reported in the literature on optimizing and then using the novel chemical/physical properties of the TiO 2 NTs/NWs, and showed at the same time the controls of the nanofibers’ morphology and special organization during the syntheses. The first generation of titania nanotube arrays via anodization was initially reported by Gong and co-workers in 2001 [12]. Later on, Grime’s group created vertically oriented TiO 2 nanotubes of 134 lm in height [13]. Miao et al. [14] have prepared large arrays of single crystalline TiO 2 nanotubes through a templated electrochemical sol-gel deposition process. In that system, TiO 2+ ionic clusters diffusing to the cathode surface are believed to undergo hydrolysis and condensation reactions, resulting in the formation of amorphous TiO 2 gel nanorods [14]. After a heat treatment at 240 8C for 24 hours in air, nanowires of single- crystal anatase TiO 2 were formed to have their diameters between 10 nm and 40 nm, and lengths ranging from 2 to 10 lm. In 2004 Sander et al. developed a template-assisted method for fabricating dense, oriented arrays of titania nanotubes with well-controlled dimensions on substrates [15]. Template-free hydrothermal synthesis of oriented TiO 2 - based nanotubes was developed by Tian et al. [16]. The strategy of using TiO 2 nanoseeds has been adapted into the syntheses of large arrays of oriented 1D nanotubes. An aqueous suspension of TiO 2 nanoparticles (Degussa P-25) was prepared for dip-coating a thin layer of TiO 2 nanoseeds on a substrate. After a hydrothermal treatment, vertically 1549-9634/$ – see front matter. Published by Elsevier Inc. doi:10.1016/j.nano.2006.10.005 No financial conflict of interest was reported by the authors of this paper. 4 Corresponding author. Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA. E-mail address: rtian@uark.edu (Z.R. Tian). Nanomedicine: Nanotechnology, Biology, and Medicine 2 (2006) 248– 252 www.nanomedjournal.com