ORIGINAL ARTICLE Evaluation of Bioactivity and Biocompatibility of Silk Fibroin/ TiO 2 Nanocomposite Narges Johari 1 • Hamid Reza Madaah Hosseini 1 • Nafise Taromi 2,3,4 • Shaghayegh Arasteh 5 • Somaieh Kazemnejad 5 • Ali Samadikuchaksaraei 2,3,4 Received: 13 August 2016 / Accepted: 15 May 2017 Ó Taiwanese Society of Biomedical Engineering 2017 Abstract Biodegradable polymer/bioceramic nanocom- posites are osteoconductive and can accelerate healing of bone tissue. In this research, silk fibroin (SF)/titanium dioxide (TiO 2 ) nanocomposites were synthesized using different concentrations of TiO 2 nanoparticles (0, 5, 10, 15 and 20 wt%). The SF/TiO 2 nanocomposites were studied in terms of bioactivity and biocompatibility. The in vitro assessment of osteoblasts compatibility indicated that SF inclusion rendered nanocomposite biocompatible whereas presence of TiO 2 nanoparticles allowed the cells to adhere and grow on nanocomposite surface and enhanced the bioactivity of the composite. Keywords Bioceramic Á Nanocomposite Á Apatite Á Titanium dioxide 1 Introduction Bone is mainly composed of inorganic Hydroxyapatite (HA) nanocrystals and the collagen fibers. The combina- tion of HA and collagen determines the mechanical properties and biological functions of bone [1]. Repli- cating such structural and compositional arrangement in synthetic biodegradable polymer/bioceramic nanocom- posites can provide a biomimetic condition for cell attachment, proliferation and differentiation [2]. To mimic the structural and compositional condition of nat- ural bone, biodegradable polymer/nano bioceramic has been widely utilized to fabricate nanocomposites with adequate osteoconductivity and osteoinductivity [3]. Silk fibroin (SF), is a biodegradable and biocompatible natural polymer, with greater potential than collagen for appli- cation in clinical repair, tissue engineering and modified materials production. SF has several hydrophilic polar groups, facilitating cell affinity [4], and can manage the mineralization of HA nanocrystals [5]. Interfacial bonding is a key factor in providing organic/inorganic composites with desirable properties [3]. Titanium dioxide (TiO 2 ) nanoparticles are a bioce- ramic which can enter the human body via different routes, like inhalation, ingestion, dermal penetration and injection [6, 7]. Titanium dioxide (TiO 2 ) is an apropos candidate for bone implant fabrication given that it has outstanding properties, such as lightness and corrosion resistance [8, 9]. Nano-TiO 2 affects adhesion, prolifera- tion and differentiation of osteoblast cells [10]. The morphology of nano-TiO 2 surface dictates the interaction with surrounding bone. The bioactive surface of TiO 2 allows for the formation of strong chemical bond with natural bone during the initial implantation stage [11]. Nevertheless, since the function of TiO 2 nanoparticles is & Hamid Reza Madaah Hosseini madaah@sharif.edu 1 Department of Materials Science and Engineering, Sharif University of Technology, Tehran 1458889694, Iran 2 Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran 1449614535, Iran 3 Department of Tissue Engineering & Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran 4 Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran 5 Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran 19615, Iran 123 J. Med. Biol. Eng. DOI 10.1007/s40846-017-0295-4