In this work, carbonated hydroxyapatite (CHA) based on abalone mussel shells (Haliotis asinina) is synthesized using the co-precipitation method. The synthesized CHA was mixed with honeycomb (HCB) 40 wt.% for the scaffold fabrication process. CHA and scaffold CHA/HCB 40 wt.% were used for coating a Titanium (Ti) alloy using the electrophoretic deposition dip coating (EP2D) method with immersion times of 10, 20, and 30 min. The synthesized B-type CHA with a stirring time of 45 min could have lower transmittance values and smaller crystallite size. Energy dispersive X-ray spectroscopy (EDS) showed that the Ca/P molar ratio was 1.79. The scaffold CHA/HCB 40 wt.% had macropore size, micropore size, and porosity of 102.02 ± 9.88 μm, 1.08 ± 0.086 μm, and 66.36%, respectively, and therefore it can also be applied in the coating process for bone implant applications due to the potential scaffold for bone growth. Thus, it has the potential for coating on Ti alloy applications. In this study, the compressive strength for all immersion time variations was about 54–83 MPa. The average compression strengths of human cancellous bone were about 0.2–80 MPa. The thickness obtained was in accordance with the thickness parameters required for a coating of 50–200 μm.

In this study, nano-carbonated hydroxyapatite (n-CHAp) was successfully synthesized with abalone shells (Halioitis asinina) as the calcium source using precipitation methods with aging time variations, namely, 0 (without the aging process), 24, and 48 h. Based on an analysis of X-ray diffraction characterization, the spectrum of the n-CHAp is shown for all sample variations in aging time. The results of the calculation of lattice parameter values confirm that the phase formed is the B-type CHAp phase with the increasing crystallinity degree, crystallite size, particle size, and polydispersity which is confirmed by the presence of the CO₃^2- functional group at 1438 cm⁻¹ and 878 cm⁻¹, that is, the B-type carbonate substitution characteristic. The presence of the carbonate ions identified as smaller during the extension of aging time causes the decreasing value of the Ca/P mole ratio but still has a value greater than the HAp Ca/P value (1.67), which is 1.80–1.72. Based on the transmission electron microscopy analysis, the nanometer-size of B-type CHAp particles was successfully obtained. According to the criteria for nanostructures, crystallographic properties, carbonate content, and chemical processes, B-type CHAp samples based on abalone shells (Halioitis asinina) are one of the candidates in bioceramics for bone tissue engineering applications.

In this work, carbonated hydroxyapatite/titanium alloy (CHA/Ti) and carbonated hydroxyapatite/honeycomb/titanium alloy (CHA/HCB/Ti) plates were coated using the electrophoretic deposition dip coating (EP2D) method. Analysis of cell viability and surface morphology of CHA/Ti and CHA/HCB/Ti coatings were carried out using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and scanning electron microscopy (SEM), respectively. In a previous study, the thickness and average compressive strength values for the CHA/Ti and CHA/HCB/Ti plates were about 63–89 μm and 54–75 MPa, respectively. The result for thickness and compressive strength in this research followed the thickness and compressive strength parameters for coating in bone implants. In this work, the cell viability for incubation times during 24 h and 48 h of CHA/Ti plates is demonstrably superior to that of CHA/HCB/Ti plates, respectively, where the cell viability for CHA/Ti plates increased to ((67 ± 2)%) after incubation for 48 h. According to the one-way analysis of variance (ANOVA), the p-value was <0.05, indicating a significant difference in the average cell viability value across the three groups. Furthermore, the surface of CHA/Ti is not changed after the coating process. These results will yield many positive biomedical applications, especially in bone implants. Overall, CHA/Ti and CHA/HCB/Ti plates can be considered candidates for biomedical applications based on an analysis of surface morphology and cell viability.

According to the Indonesian Ministry of Health Research and Development Agency's 2018 Basic Health Research (Riskesdas), bone defects, because of fracture cases in Indonesia, reached a prevalence of 5.5%. Bone tissue engineering is one of the most promising new approaches for accelerating the growth and healing of bone defects in patients. In this study, a bone scaffold electrospun nanofiber composed of hydroxyapatite (HA)-polycaprolactone (PCL)-collagen was fabricated to mimic the extracellular matrix (ECM) found in native bone tissue and to promote bone remodeling and healing. Through characterization of functional groups with Fourier transform infrared (FTIR), morphology scanning electron microscopy (SEM), tensile strength test, degradation test, and cytotoxicity MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, this study determines the optimal composition of electrospun nanofiber HA/PCL/collagen to obtain the best candidate of a bone scaffold with excellent characteristics. Electrospinning was used to fabricate bone scaffolds. The samples used in this study consisted of control samples, namely PCL-HA and PCL-Collagen, and three samples with a mass ratio composition of HA-PCL-collagen 50:40:10, 50:30:20, and 50:25:25 (w/v%). The FTIR analysis of the sample revealed that no chemical bond existed between the materials. The HA/PCL/collagen 50:25:25 (F3) sample exhibited the best characteristics as a bone scaffold candidate, with a fiber diameter of 365 ± 202 nm; a porous fraction area of 58.98%; an ultimate tensile strength, and an elasticity modulus of 0.60 ± 0.185 and 5.98 ± 0.82 MPa, respectively; a degradation rate of 1.93 × 10⁻⁶ g/h; and cell viability of 81.03%. Graphical Abstract

Porosity is one of the parameters of scaffold pore structure that must be developed using paraffin wax as a synthetic polymer for making porous bioceramics carbonated hydroxyapatite (CHA). This study fabricated CHA based on abalone mussel shells (Halioitis asinina); CHA/paraffin wax nanocomposite scaffolds were synthesized using paraffin wax with concentration variations of 10, 20, and 30 $\mathrm{wt}.\%$. The energy-dispersive X-ray spectroscopy (EDS) results showed that the Ca/P molar ratio of CHA was 1.72, which approaches the natural bone. The addition of paraffin wax in all concentration variation treatments caused the crystallographic properties of the CHA/paraffin wax nanocomposite scaffolds to decrease. The results of pore analysis suggest that the high concentration of paraffin wax in the CHA suspension is involved in the formation of more pores on the surface of the scaffold, but only CHA/paraffin wax 30 $\mathrm{wt}$.% had a scaffold with potential to be used in media with a cellular growth orientation. The micropore analysis was also supported by the cell viability assay results for CHA/paraffin wax 30 $\mathrm{wt}$.% nanocomposite scaffold, where serial doses of scaffold concentrations to mouse osteoblast cells were secure. Overall, based on this analysis, the CHA/paraffin wax scaffold can be a candidate for bone tissue engineering.