Journal of Materials Science: Materials in Medicine (2019)30:24 https://doi.org/10.1007/s10856-019-6224-z TISSUE ENGINEERING CONSTRUCTS AND CELL SUBSTRATES Original Research Enhanced mesenchymal stem cell proliferation through complexation of selenium/titanium nanocomposites Hanaa H. Ahmed 1,2 ● Hadeer A. Aglan 1,2 ● Mostafa Mabrouk 3 ● Ahmed A. Abd-Rabou 1,2 ● Hanan H. Beherei 3 Received: 23 April 2018 / Accepted: 19 January 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract The main target of this work was to explore the proliferative impact of selenium dioxide nanoparticles (SeO 2 ) and selenium dioxide/titanium dioxide nanocomposites (Se/Ti (I), (II) and (III)) on mesenchymal stem cells (MSCs). For this purpose, SeO 2 and Se/Ti (I), (II) and (III) were prepared by facile one step method and characterized by transmission electron microscopy (TEM), Zetasizer, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) along with energy-dispersive X-ray spectrometry (EDX) with reference to SeO 2 nanoparticles. Also, MSCs were isolated from rat bone marrow (BM-MSCs) and adipose tissue (ADSCs), propagated and characterized by flow cytometry. Thereafter, the proliferative effect of the fabricated nanomaterials was investigated by MTT assay. The TEM and DLS results, revealed that the average particle size of the suggested nanomaterials was in nanoscale. XRD pattern showed well crystalline structure for SeO 2 nanoparticles and Se/Ti (I), (II) and (III) nanocomposites; the decreasing of the crystalline phase was observed by increasing the wt% of TiO 2 . The designed nanomaterials showed proliferative effects on MSCs with the most prominent effect exerted by 2 μg/ml of Se/Ti (III) and 5 μg/ml of Se/Ti (II) for ADSCs and 20 μg/ml of Se/Ti (II) and 10 μg/ml of Se/Ti (III) for BM-MSCs. Therefore, these newly designed nanomaterials have a promising influence on MSCs proliferation and they are recommended to be utilized in the filed of tissue engineering. 1 Introduction Nanoparticle is an expression used recently for those materials that are below 100 nm in size or at least one dimension is smaller than 100 nm [1]. Owing to their novel physical and chemical properties compared with the con- ventional particles, plenty of scientists are concerned with the fabrication and the development of nanoparticles. These nanoparticles have opened new opportunities for applica- tions in a variety of fields, such as chemical industry, agriculture, cosmetics, and medicine [2, 3]. Several studies have been reported on rare earths and cells interactions, such as gadolinium (Gd) effect on the mouse osteoblast cells [4], selenium nanoparticles (Se) influence on the cell permeabilization of human hepatocellular carcinoma (HepG2) [5], impact of lanthanum (La) ions on the osteo- blasts differentiation [6], ytterbium (Yb) insult on the apoptosis of bone marrow stromal cells [7] and burden of adding pearl powder (PP) to magnesium alloys on osteo- blasts cells [8]. However, up to our knowledge the effect of selenium dioxide on stem cells proliferation is not reported till now. Selenium belongs to the nonmetal rare earth elements with properties that are intermediate between tellurium and sulfur. Selenium is a unique nonmetal chemical element with five valence states (+ 6, + 4, + 2, 0, -1, -2) [9]. Moreover, Se nanoparticles exhibited a high biological activity and good absorptive ability due to the interaction between –NH 2 ,C = O, -COO, and –C–N– groups of proteins and the nanoparticles of Se [10]. In addition, selenium was proved to stimulate the cell cycle progression and to prevent cell death. Meanwhile, Se is very unstable and easily changes into the inactive form [11]. Till today, titanium (Ti) complexation with Se (metal metal * Hanaa H. Ahmed hanaaomr@yahoo.com 1 Hormones Department, National Research Centre, Giza, Egypt 2 Stem Cells Lab, Center of Excellence for Advanced Sciences, National Research Centre, Giza, Egypt 3 Refractories, Ceramics and Building Materials Department, National Research Centre, Giza, Egypt 1234567890();,: 1234567890();,: