Colloids and Surfaces B: Biointerfaces 136 (2015) 1089–1097 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces journal homepage: www.elsevier.com/locate/colsurfb Multifunctional nano manganese ferrite ferrofluid for efficient theranostic application Ansar Ereath Beeran a , Francis Boniface Fernandez b , Shaiju S. Nazeer c , Ramapurath S. Jayasree c , Annie John b , Sukumaran Anil d , Sajith Vellappally d , Abdul Aziz A. Al Kheraif d , P.R. Harikrishna Varma a,∗ a Bioceramics Laboratory, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, India b Transmission Electron Microscopy Laboratory, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, India c Biophotonics and Imaging Lab, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, India d Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia a r t i c l e i n f o Article history: Received 28 July 2015 Received in revised form 2 November 2015 Accepted 5 November 2015 Available online 10 November 2015 Keywords: Superparamagnetic nanoparticle Manganese ion Magnetic resonance imaging Hyperthermia Theranostic a b s t r a c t Ferrofluid-based manganese (Mn 2+ ) substituted superparamagnetic iron oxide nanoparticles stabilized by surface coating with trisodium citrate (MnIOTCs) were synthesized for enhanced hyperthermic activ- ity and use as negative magnetic resonance imaging (MRI) contrast media intended for applications in theranostics. The synthesized MnIOTC materials were characterized based on their physicochemical and biological features. The crystal size and the particle size at the nano level were studied using XRD and TEM. The presence of citrate molecules on the crystal surface of the iron oxide was established by FTIR, TGA, DLS and zeta potential measurements. The superparamagnetic property of MnIOTCs was measured using a vibrating sample magnetometer. Superparamagnetic iron oxide substituted with Mn 2+ with a 3:1 molar concentration of Mn 2+ to Fe 2+ and surface modified with trisodium citrate (MnIO75TC) that exhibited a high T 2 relaxivity of 184.6 mM −1 s −1 and showed excellent signal intensity variation in vitro. Hyperthermia via application of an alternating magnetic field to MnIO75TC in a HeLa cell population induced apoptosis, which was further confirmed by FACS and cLSM observations. The morphological features of the cells were highly disrupted after the hyperthermia experiment, as evidenced from E-SEM images. Biocompatibility evaluation was performed using an alamar blue assay and hemolysis studies, and the results indicated good cytocompatibility and hemocompatibility for the synthesized particles. In the current study, the potential of MnIO75TC as a negative MRI contrast agent and a hyperthermia agent was demonstrated to confirm its utility in the burgeoning field of theranostics. © 2015 Published by Elsevier B.V. 1. Introduction Over the last decade, several attempts have been made to syn- thesize iron oxide nanoparticles suitable for various biomedical applications due to their magnetic, hyperthermic and MRI contrast properties. Delivery of the dual properties of diagnosis and ther- apy in a single unit is ideal for optimum use of these particles for individualized treatment, and this mode of treatment, known as theranostics, has aimed to revolutionize interventional medical care in this decade [1–3]. Over the last few years, sufficient efforts have been reported for synthesis of stable, biocompatible and highly dis- ∗ Corresponding author. Fax: +91 471 2341814. E-mail address: varma@sctimst.ac.in (P.R.H. Varma). persed colloidal nanoparticles, and a number of interesting findings of their unique applications in vivo have been reported. [4–6]. Numerous non-invasive techniques [7], such as near infrared (NIR optical or fluorescence) imaging, a combination of therapeu- tic pulsed laser light with plasmonic particles (gold nanocrystals [8] or carbon nanotubes [9]), computed tomography (CT) via an X- ray source, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) [10], are currently used in the clinical field for bioimaging applications. The main limitations of these techniques include poor penetration depth [11] and dam- age to live tissues due to the high-energy sources involved [12]. To overcome these limitations, magnetic nanoparticle-mediated magnetic resonance imaging and hyperthermia interventions have been proposed for theranostic applications [13,14]. Magnetic nanoparticles, especially spinel nanoferrites, have been reported for proton spin–spin relaxation [T 2 ] contrast http://dx.doi.org/10.1016/j.colsurfb.2015.11.010 0927-7765/© 2015 Published by Elsevier B.V.