Open Access. © 2020 Z. Tabia et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 License Biomed. Glasses 2020; 6:10ś22 Research Article Zakaria Tabia, Sihame Akhtach, Khalil El Mabrouk*, Meriame Bricha, Khalid Nouneh, and Anbalagan Ballamurugan Tantalum doped SiO 2 -CaO-P 2 O 5 based bioactive glasses: Investigation of in vitro bioactivity and antibacterial activities https://doi.org/10.1515/bglass-2020-0002 Received Jan 27, 2020; revised Apr 13, 2020; accepted Apr 25, 2020 Abstract: Multifunctionality can be achieved for bioactive glasses by endowing them with multiple other properties along with bioactivity. One way to address this topic is by doping these glasses with therapeutic metallic ions. In this work, we put under investigation a series of bioac- tive glasses doped with tantalum. We aim to study the ef- fect of tantalum, on the structure, bioactivity and antibac- terial property of a ternary bioactive glass composition based on SiO 2 -CaO-P 2 O 5 . Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Difraction (XRD) and Electron Scanning Microscopy (SEM) were used to assess the struc- tural and morphological properties of these glasses and monitor their changes after in vitro acellular bioactivity test. Antibacterial activity was tested against gram positive and negative bacteria. Characterization results confrmed the presence of calcium carbonate crystallites along with the amorphous silica matrix. The assessment of bioactiv- ity in SBF indicated that all compositions showed a fast bioactive response after only six hours of immersion pe- riod. However, analytical characterization revealed that tantalum introduced a slight latency in hydroxyapatite de- position at higher concentrations (0.8-1 %mol). Antibacte- rial test showed that tantalum ions had an inhibition efect on the growth of E. coli and S. aureus. This efect was more pronounced in compositions where mol% of tantalum is superior to 0.4%. These results proved that tantalum could be used, in intermediate proportions, as a promising mul- tifunctional dopant element in bioactive glasses for bone regeneration applications. Keywords: tantalum; bioactive glass; bioactivity; antibac- terial property, bone regeneration *Corresponding Author: Khalil El Mabrouk: Euromed Re- search Center, Euromed Engineering Faculty, Euromed Univer- sity of Fes, Eco-Campus, Meknes Road, 30 030, Fes, Morocco; Email: k.elmabrouk@ueuromed.org; Tel: + 212 662 054 920; Fax: +212 537 716 040 1 Introduction Biomaterials for bone regeneration are one of the most active research felds nowadays. The aim is to conceptu- alize and study new materials that can elicit promising biological and mechanical responses for stimulating and withstanding bone regeneration [1]. In the way of the en- deavor to search the ideal biomaterial for bone healing, several breakthroughs have been made, among which the discovery of bioactive glasses by Professor L. Hench in 1969 [2, 3]. Since then, these inorganic materials have had, themselves, major advancements. Beginning with the in- troduction of sol-gel as a synthesis method [4] and its combination with supra-molecular chemistry to produce mesoporous materials through evaporation induced self- assembly (EISA) [5, 6], bioactive glasses have become a re- search feld of its particular interest. Two characteristics considered of utmost importance for biomaterials in general, and bioactive glasses in partic- ular, are bioactivity and antibacterial property [7, 8]. Bioac- tive glasses make excellent candidates to be used as multi- functional materials that can stimulate new bone forma- tion along with being anti-infective [9]. From a clinical point of view, experts have always seen bacterial infec- tions as a major challenge for tissue regeneration and re- pair as they can lead to implant failure and prolonged heal- ing of the bone defect [10, 11]. These infections which arise mainly from nosocomial contamination during surgery Zakaria Tabia: Euromed Research Center, Euromed Engineering Faculty, Euromed University of Fes, Eco-Campus, Meknes Road, 30 030, Fes, Morocco; Laboratory of Physics and Condensed Matter, Department of Physics, Ibn Tofail University, Kenitra, Morocco Sihame Akhtach, Meriame Bricha: Euromed Research Center, Euromed Engineering Faculty, Euromed University of Fes, Eco- Campus, Meknes Road, 30 030, Fes, Morocco Khalid Nouneh: Laboratory of Physics and Condensed Matter, Department of Physics, Ibn Tofail University, Kenitra, Morocco Anbalagan Ballamurugan: Department of Nanoscience and Tech- nology, Bharathiar Coimbatore, Tamil Nadu, India