Rapid Communication Electrosprayed titania nanocups for protein delivery A. Sandeep Kranthi Kiran, K. Madhumathi, T.S. Sampath Kumar ⁎ Medical Materials Laboratory, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036, India abstract article info Article history: Received 19 August 2015 Received in revised form 6 April 2016 Accepted 8 April 2016 Available online xxxx This communications paper presents an innovative, reproducible and scalable method of producing phase pure titania (TiO 2 ) nanocups by electrospraying using titania isopropoxide (TIP) as precursor with polyvinyl acetate (PVAc) as a polymer and also discusses about the protein delivery of synthesized TiO 2 nanocups. PVAc-TIP was electrosprayed to form particles with cup morphology at room temperature which was later converted into an- atase TiO 2 by controlled heating up to 550 °C while retaining the shape. The as-synthesized and calcined samples were characterized by SEM, TEM, DLS, XRD and FT-IR techniques. The loading and release profile of bovine serum albumin (BSA) by the nanocups showed a maximum loading and sustained release as compared to electrosprayed spherical TiO 2 nanoparticles using the same precursors and heating conditions. © 2016 Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Interest in titania (TiO 2 ) nanoparticles have grown exponentially in the fields of medicine (drug delivery, gene delivery, tissue engineering) [1–3], sensors (solar cells) [4] and as a coating material in environmental remediation due to its biocompatibility, high chemical stability, large sur- face area to volume ratio, distinctive surface characteristics, attractive physical, optical and photocatalytic properties. TiO 2 nanoparticles exhibit antibacterial activity and anti-cancer activity, which is ascribed to its pho- tocatalytic properties. Many methods like mechanochemical processing [5], micro-emulsion [6], sol–gel [7], and hydrothermal crystallization [8] have been used to produce TiO 2 of particulate morphology. Among the methods, electrospraying has evolved to be a very simple, versatile, and effective technique to fabricate nanostructures with sophis- ticated geometries like nanorods [9], nanofibers [10], nanobeads [11], and nanotubes of size ranging from few hundred micrometers to tens of nano- meters by varying the spinning/spraying parameters (process, solution and polymer). In short, electrospraying uses relatively low polymer con- centration of solution in comparison to electrospinning. The low viscous solution is held at the nozzle tip of the syringe due to surface tension. When the strength of electric field exceeds the critical voltage, the jet breaks down into fine droplets and results in spraying of particles than spinning of fibers. Recently, there is a great demand for hollow nanostructures owing to their unique properties such as extremely large surface area and easy transport channels compared to other nanostructures. Chang et al. were the first to demonstrate the feasibility of producing a hollow microsphere of polymethylsilsesquioxane with a single hole in its shell by coaxial electrohydrodynamic atomization [12].The nanocups are more preferred than the popular hollow nanospheres and hollow nanofibers for high performance drug delivery applications as they have higher loading ca- pacity due to their inner cavities [13]. Recently, a novel ultrasound- responsive polymeric nanocups capable of enhanced distribution of IgG mouse antibody in an in vivo tumor model has been developed [14]. Also, gold nanoparticle-containing microbubbles were produced by pres- surized gyration using a protein solutions (PVAlysozyme). The microbubbles were found to have increased antibacterial activity and bet- ter bio-sensing capabilities compared to that of the bare protein microbubbles [15,16]. Formation of porous titania nanocup-shaped nanoparticles by electrospraying has been reported using polymethylmethacrylate (PMMA) blending with titanium isopropoxide (Ti [OC 3 H 7 ] 4 ) in a solvent mixture of nitromethane and acetic acid followed by thermal treatment at 550 °C [17]. Recently, anatase phase TiO 2 nanocups were synthesized by coating TiO 2 on spherical SiO 2 template followed by annealing the SiO 2 /TiO 2 nanospheres at 500 °C [18]. However, these studies have been focused only on the formation of hollow particles and not evaluated the development of nanocups form nanoparticles. Also, to the best of avail- able literature, there were no studies on the application of TiO 2 nanocups for protein delivery. In this work, we report the effect of process parameters for the repro- ducible fabrication of TiO 2 nanocups by electrospraying and its protein delivery profile using bovine serum albumin (BSA), a model protein. BSA was chosen due to its medical importance and favorable ligand- binding properties. The effect of nanocup morphology on loading and re- lease of protein was evaluated by comparing the results with TiO 2 nano- particles formed by electrospraying prepared under similar synthesis conditions. The electrospraying solution was prepared by adding 3–4 wt.% re- quired amount of PVAc (Polyvinyl acetate, Mn-1,00,000, Sigma) to 4 ml toluene and was continuously stirred in a magnetic stirrer for 3 h to obtain Colloids and Interface Science Communications 12 (2016) 17–20 ⁎ Corresponding author. E-mail address: tssk@iitm.ac.in (T.S. Sampath Kumar). http://dx.doi.org/10.1016/j.colcom.2016.04.001 2215-0382/© 2016 Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Contents lists available at ScienceDirect Colloids and Interface Science Communications journal homepage: www.elsevier.com/locate/colcom