Materials Technology Advanced Performance Materials ISSN: 1066-7857 (Print) 1753-5557 (Online) Journal homepage: https://www.tandfonline.com/loi/ymte20 Advanced 3Y-TZP bioceramic doped with Al2O3 and CeO2 potentially for biomedical implant applications Mohsen Golieskardi, Meenaloshini Satgunam, Dinesh Ragurajan, Md Enamul Hoque, Angela Min Hwei Ng & Lohashenpahan Shanmuganantha To cite this article: Mohsen Golieskardi, Meenaloshini Satgunam, Dinesh Ragurajan, Md Enamul Hoque, Angela Min Hwei Ng & Lohashenpahan Shanmuganantha (2019): Advanced 3Y-TZP bioceramic doped with Al2O3 and CeO2 potentially for biomedical implant applications, Materials Technology To link to this article: https://doi.org/10.1080/10667857.2019.1578912 Published online: 20 Feb 2019. Submit your article to this journal View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ymte20 MATERIALS TECHNOLOGY https://doi.org/10.1080/10667857.2019.1578912 Advanced 3Y-TZP bioceramic doped with Al2O3 and CeO2 potentially for biomedical implant applications Mohsen Golieskardia, Meenaloshini Satgunama, Dinesh Ragurajan a, Md Enamul Hoqueb, Angela Min Hwei Ngc and Lohashenpahan Shanmugananthac aDepartment of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional, Kajang, Malaysia; bDepartment of Biomedical Engineering, Military Institute of Science and Technology (MIST), Dhaka, Bangladesh; cTissue Engineering Center, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia ABSTRACT ARTICLE HISTORY This research studies 3 mol% yttria-stabilized zirconia (3Y-TZP) investigating the effects of Al2O3 Received 3 October 2018 Accepted 21 January 2019 and CeO2 dopants on the stability of tetragonal phase and the microstructure of 3Y-TZP determined over the operating temperature ranging from 1250°C to 1550°C. It is found that KEYWORDS the mechanical properties of 3Y-TZP are dependent on the sintering temperature and the dopant Bioceramic; 3Y-TZP; cell amount. The current study reveals that the optimum sintering temperature is 1450°C for all 3Y- morphology; cell 3 TZP samples while attaining more than 98% of the theoretical density (6.1g/cm ). With optimum proliferation; cytotoxicity; dopants, the 3Y-TZP ceramic samples demonstrate the Vickers hardness of 10.9 GPa and fracture mechanical properties 1/2 toughness (KIC)of10MPa.m . Fracture toughness increases with the dopant content, indicating that the annihilation of oxygen vacancies in 3Y-TZP is responsible for the instability of the t-ZrO2 lattice. To investigate the biocompatibility of 3Y-TZP, cell culture study was performed using osteoblast cells. The results demonstrate a high percentage of cell attachment and proliferation that confirmed the biocompatibility of synthesized 3Y-TZP. Introduction size ~0.5 μm) from Y-TZP powders. The fracture toughness, hardness and fracture strength of 3Y-TZP Biomaterials are implanted in human bodies to replace are 4–8 MPa.m1/2,10–12 GPa and 900–1200 MPa, damaged/diseased tissues. As for the developments in respectively [9], which are relatively high as compared implantology field, many materials have been invented to those of other bioceramics [10]. The superior fracture to improve prostheses quality applied for either fixing toughness exhibited by Y-TZP ceramics are due to the or replacing the body tissues. Since most of the bioma- transformation toughening mechanism, which involves terials used for this purpose are ceramics, metals and spontaneous phase transformation from tetragonal (t) polymers, spectacular improvements have occurred in to monoclinic (m) zirconia occurring as a crack propa- many cases such as bone reconstruction, and replacing gates through the material, a mechanism known as joints or teeth. The overall innovations on both surface transformation toughening [11]. properties and bulk modifications in this regards are However, one of the major limitations of Y-TZP enormous. When prosthesis is placed within the body, ceramics as engineering materials is the undesirable it interacts with the living organs. Therefore, it is impor- surface-initiated phase transformation from the (t) to tant that the material should be biocompatible, e.g. (m) symmetry accompanied by property degradation a successful implant provides enough material tolerance during exposure in humid atmosphere (water and to support a higher biocompatibility grade. steam) at temperatures ranging from 20°C to 500°C. A biomaterial can be produced from various sources Besides, ceramic can undergo a slow, tetragonal to such as metal, polymer or ceramic, depending on its monoclinic phase transformation at the samples surface functionality [1–5]. There are advantages and limita- in a humid atmosphere followed by microcracking and tions associated with each material category. For exam- a serious loss in strength, a phenomenon subsequently ple, ceramic is well-known for its biocompatibility. known as ageing or low-temperature degradation However, it is frequently characterized by its high hard- (LTD) [12–14]. ness and low resistance to fracture. On the other hand, To overcome LTD in Y-TZP, inclusion of sintering bioceramics such as 3 mol% yttria-stabilized zirconia additivessuchasTiO,SiO,AlO ,MgO,CeO, etc. (3Y-TZP), porcelain are often used in dental applica- 2 2 2 3 2 have been investigated by many researchers since this is tions due to their biocompatibility and promising the most effective and simplest way to achieve a dense mechanical properties [6–8]. More importantly, very body at low-temperature sintering, thus helps to fine grain microstructures may be obtained (particle CONTACT Mohsen Golieskardi [email protected] Department of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional, 43000 Kajang, Malaysia © 2019 Informa UK Limited, trading as Taylor & Francis Group 2 M. GOLIESKARDI ET AL. improve the mechanical properties of the sintered (20 mm diameter) and bars (4mmx material [15–20]. Samodurova [21] reported that com- 13mmx32mm) and underwent cold-isostatic press- bined effect of alumina and silica (up to 0.25 wt%) co- ing at 200 MPa before being sintered at various doping to 3Y-TZP results in improved resistance to temperatures (1250°C −1550°C), with a ramp rate ageing without affecting the mechanical properties. of 10°C/min and holding time of 2 h. Small addition of Al2O3 (<5%) is able to promote den- sification of Y-TZP ceramic. It is observed that small addition of Al2O3 could enhance sintering at low tem- Physical and mechanical characterizations peratures and cause impressive grain growth at higher The bulk densities of samples were determined using sintering temperatures. the Archimedes method (Mettler-Toledo AG204). Microstructure of the ceramics can be altered, Firstly, the samples were polished before their leading to dispersion strengthening through various Vickers hardness (Hv) values were measured using mechanisms [22–24] that eventually enhances the micro-indentation. During the test, a load of 1 kg was mechanical property of the material. The effects of exerted using a pyramidal jewel indenter for 10 s. Ten Al O and 3Y-TZP ceramic composites in vivo envir- 2 3 measurements were performed on each sample. On onment have been studied by Santos et al. [25]. This the other hand, the K values of all samples were analysis showed promising results, because the viabi- IC determined by measuring the cracks created upon lity of 90% of the composite material was clearly exerting a load of 2 kg for 10 s. The crack was above the 80% viability limit, which indicates an analyzed by using an image analysis program. Here, excellent biocompatibility of the material. Therefore, the equation proposed by Niihara et al. was employed it can be affirmed that the 3Y-TZP–Al O composite 2 3 [27]. The measurement was repeated 10 times for material can be classified as non-cytotoxic and there- each sample. fore having great potential for possible applications as implants. Another attractive dopant for the stabiliza- tion of 3Y-TZP is cerium oxide. It has been reported Cell culture study that the minor addition of cerium oxide (up to 0.5 wt %) to 3Y-TZP results in improved resistance to age- 2x105 cultured human osteoblasts (Passage 3 or 4) ing without affecting the mechanical properties. Rejab were seeded onto each Al2O3/CeO2 (either with the et al. [26] indicated that through increasing CeO2 ratio of 0.3/0.3 or 0.3/0.5) disc placed in a 24 well content the bulk density was increased and the per- plate. After 24 h, seeded discs were shifted to a new centage of porosity was decreased. This can improve 24-well plate. At day 1, day 4 and day 7, the seeded the toughness of the materials. discs were transferred to a new plate. At the respec- The aim of this work is to study the influence of tive time points, 40ul of PrestoBlue™ Reagent the combined effects of aluminium oxide and cerium (Invitrogen, USA) was added directly into the well oxide co-doping on the densification, Vickers hard- with 360ul of culture medium containing the ness, fracture toughness and cytotoxicity of 3 mol% seeded discs. The seeded disc samples placed into yttria-stabilized zirconia materials commonly utilized thewell-platewereincubatedfor2hat37ºC.After in the implants. incubation, the well-plate was shaken mildly for more uniform distribution of seeded cells into the disc samples, and transferred 100ul of the reaction Experimental procedures mix (in triplicates) into a 96-well plate. Absorbance was read at 570nm with a reference wavelength of Synthesis of 3Y-TZP ceramic and preparation of 600nm using a microplate reader (BioTek, USA). test samples Living cells that are metabolically active will reduce The starting materials used were as-received com- the non-fluorescent dye resazurin to a strongly mercial 3 mol% Y-TZP (Kyoritsu, Japan) cerium fluorescent dye resorufin. Absorbance is propor- oxide and aluminium oxide powders of 99.9% tional to the number of viable cells. Seeded discs purity (Sigma Aldrich). The 3 mol% Y-TZP pow- after the Presto Blue assay at Day 7, were subse- der was combined with various percentages of quently incubated in culture media twice for 24 aluminium oxide and cerium oxide powders; i.e.