An Experimental Study of Porous Hydroxyapatite Scaffold Bioactivity in Biomedical Applications

Abstract

Hydroxyapatite, Scaffold, Bone Regeneration, Bioactivity. Hydroxyapatite is one of the most bioactive materials used in tissue engineering due to its excellent biocompatibility and chemical composition which is equivalent to the mineral element of bone. In this study, polymer sponge replication method was used to fabricate porous hydroxyapatite scaffolds. Pure phase of hydroxyapatite scaffolds and the chemical bonding were verified via Fourier Transform Infrared and X-ray diffraction. Emission scanning electron microscopy (F E S E M) examination showed that the proposed scaffold has high interconnected pores that were achieved just after sintering at temperatures 1350 oC for 2 hours. The percentage porosity values were estimated to be between 75–78 percent. The bioactivity of porous scaffolds was also investigated. They were submerged in a slurry of simulated body fluid (S B F) for seven, fourteen, and twenty-one days, respectively. Both FESEM and XRD analysis have confirmed the bioactivity of the prepared porous hydroxyapatite scaffold through the formation of a dense layer of apatite on its surface. Based on the results, the porous hydroxyapatite scaffolds could be recommended as a critical option for bone defects as well as replacement applications. How to cite this article: A. A. Mehatlaf, A. A. Atiyah, and S. B. H. Farid “An Experimental Study of Porous Hydroxyapatite Scaffold Bioactivity in Biomedical Applications,” Engineering and Technology Journal, Vol. 39, No. 06, pp. 977-985, 2021. DOI: https://doi.org/10.30684/etj.v39i6.2059 Engineering and Technology Journal Vol. 39, (2021), No. 06, Pages 977-985 978 By medical evolution, bone regeneration is recently recognized as a new medical technique for tissue engineering scaffolds including bioavailability, sufficient mechanical strength, strong interconnection, and biodegradability. Macro/ nanoporous connected morphology and Composition are thought to be important in affecting cellular responses to tissue engineering scaffolds [1]. Biomaterials are useful in making equipment to substitute apart or function of the body when needed, economically physiologically and reasonable, adequate. Diverse equipment and materials are being used in the treatment of diseases and injuries [2]. Bone grafting has become a surgical technique that replaces damaged bone either with patientderived material or, synthetic, an artificial, or natural replacement. Bone is a metabolism tissue that can adapt its structure to mechanical stimulation and repair structural damage via the healing process [3]. A number of bone grafting scaffolds now accessible have developed the utilization of bone graft for treatment, repair, either strengthen skeletal fractures and broken bones. Even so, biologically active, the precise mixture of sufficient mechanical, Low-cost scaffolding materials is constantly being studied for such purposes [4]. In the manufacturing of scaffolds, both natural and synthetic biomaterials are used. Systems for bone tissue engineering include bone regeneration following tissue loss owing to degenerative surgical procedures [5]. The scaffolds act mainly for osteoconductive moieties, allowing new bone to be deposited via creeping replacement with neighboring living bone, and secondarily as a promoter for the creation of new centers with bone regeneration by osteogenesis, which happens before implantation via cell seeding [6]. A scaffold for bone tissue regeneration must meet the following requirements to conduct such a role, include biocompatibility, biodegradability, and porosity, as well as comparable mechanical properties to that of the tissue regeneration site substituted hydroxyapatite and Collagen, which are the most common components of the human bone (a type of natural bioceramics that can be contained in the tooth)[7]. Hydroxyapatite (HA) was perhaps the majority of essential thermodynamic stability calcium phosphate inorganic constitute under the human skeletal structure in the pathological environment. Synthesized HA has many main advantages, including deliberate biodegradability in physiological conditions, biocompatibility, osteoconductive and osteoinductive abilities [8]. The interconnected pore could provide good conditions for bone regeneration and osseointegration, porous scaffolds have received a lot of attention to the application of tissue engineering applications. Porous hydroxyapatite would be a more easily bioabsorbable and osteoconductive component than bulk HA, and it was utilized as a material for artificial bone grafts in many research and field testing [9–11]. To satisfy the requirements, to attempt to develop porous scaffolding, many processing techniques have been used. Sponge replication method [12], Slip casting [13, 14], solvent casting [15], gas foaming [16] and freeze casting [17] are among the most common techniques of all. Bioactive ceramics may produce an alike bone similar to the apatite layer if they are, then they will be soaked in simulated body fluid (S B F). SBF is nearly a media with the same components as human extracellular fluid concerning inorganic elements. There are no cells and proteins in SBF, This means that the biomaterials chemical reactions with the fluid surrounding create the layer of the apatite. Therefore, it is predicted that new biomaterials will be produced by controlling the chemical properties of body fluid materials [18]. The purpose of this research was to fabricate porous scaffolds of the HA that have connected pores via utilizing the methods of foam replication, based on the restrictions related to many other techniques. To investigate bone regeneration support from this form of HA, these scaffolds, which were constructed similar to that of human trabecular bone with the micro-structure, then were used. 2. EXPERIMENTAL WORK I. Hydroxyapatite Scaffolds Synthesized The polymer replication process was used to produce a hydroxyapatite scaffold utilizing a polyurethane (PU) foam as an organic template. Parts of commercial PU sponge with cube farm form (1x1x1 cm 3 ) are utilized in the preparation. A weight percentage for HA slurry was prepared via stirring for one hour to obtain the homogeneous slurry including 60 wt. % HA powder and 3 wt. % polyethyleneglycol as just a binder. The PU sponges also were immersed throughout the slurry until all the void spaces had been removed. A body specimen was dried for 10 hours in an oven of about Engineering and Technology Journal Vol. 39, (2021), No. 06, Pages 977-985 979 80 ° C. Finally, the dried cubic samples were treated via the sintering in the furnace for 2 hours at 1350 ° C to achieve the HA scaffolds with the required properties for biodegradable implant material as shown in Figure 1. Figure 1: Heating cycle of the sintering process at 1350°C (a), HA scaffold before sintering (b), after sintering (c). 3. CHARACTERIZATIONS I. Spectroscopy Analysis The scaffolds Fourier Transform Infra-Red (FTIR) spectra were discovered to use a BRUKER, Germany, scanner with such a scanning range from 450-4000 cm -1 to acquire crucial information’s about so many different chemical bonds. II. X-ray diffraction Analysis Utilized the XRD diffractometer, a designed HAP scaffold was characterized via x-ray diffraction (XRD-6000, NF type). Cu-K radiation has been utilized with an X-ray over even a twodegree range of 10° to 90° at a rate of five degrees per minute. The phase identification was done by matching a database of diffraction to JCPDS standards. III. Measurement of Porosity Equations (1) & (2) were used to calculate the scaffold porosity form of the density retained [19].