“…In this work, the growth of grains occurs in the c-axis in the samples treated at temperatures higher than 1000 °C, which agrees with previous reports for the growth of HAp crystals 56 , 57 . This growth generates intergranular voids of greater size than those observed in the samples’ images obtained with lower temperatures.…”
Biogenic hydroxyapatite (BHAp) is a widely used material in the biomedical area due to its similarities with the bone tissue mineral phase. Several works have been spotlighted on the thermal behavior of bone. However, little research has focused on determining the influence of calcination temperature in the physicochemical and bioactive properties of BHAp. In this work, a study of the physicochemical properties’ changes and bioactive response of BHAp produced from porcine femur bones using calcination temperatures between 900 to 1200 °C was conducted. The samples’ structural, morphological, and compositional changes were determined using XRD, SEM, and FTIR techniques. XRD results identified three temperature ranges, in which there are structural changes in BHAp samples and the presence of additional phases. Moreover, FTIR results corroborated that B-type substitution is promoted by increasing the heat treatment temperature. Likewise, samples were immersed in a simulated biological fluid (SBF), following the methodology described by Kokubo and using ISO 23317:2014 standard, for 3 and 7 days. FTIR and SEM results determined that the highest reaction velocity was reached for samples above 1000 °C, due to intensity increasing of phosphate and carbonate bands and bone-like apatite morphologies, compared to other temperatures evaluated.
“…In this work, the growth of grains occurs in the c-axis in the samples treated at temperatures higher than 1000 °C, which agrees with previous reports for the growth of HAp crystals 56 , 57 . This growth generates intergranular voids of greater size than those observed in the samples’ images obtained with lower temperatures.…”
Biogenic hydroxyapatite (BHAp) is a widely used material in the biomedical area due to its similarities with the bone tissue mineral phase. Several works have been spotlighted on the thermal behavior of bone. However, little research has focused on determining the influence of calcination temperature in the physicochemical and bioactive properties of BHAp. In this work, a study of the physicochemical properties’ changes and bioactive response of BHAp produced from porcine femur bones using calcination temperatures between 900 to 1200 °C was conducted. The samples’ structural, morphological, and compositional changes were determined using XRD, SEM, and FTIR techniques. XRD results identified three temperature ranges, in which there are structural changes in BHAp samples and the presence of additional phases. Moreover, FTIR results corroborated that B-type substitution is promoted by increasing the heat treatment temperature. Likewise, samples were immersed in a simulated biological fluid (SBF), following the methodology described by Kokubo and using ISO 23317:2014 standard, for 3 and 7 days. FTIR and SEM results determined that the highest reaction velocity was reached for samples above 1000 °C, due to intensity increasing of phosphate and carbonate bands and bone-like apatite morphologies, compared to other temperatures evaluated.
“…In Figure 5a, the images reveal aggregate mineral crystals with varying sizes. The histogram, Figure 5b, relates to frequency and particle size, with a central peak of 643.50 nm representing the most common value, this is in agreement with the result of the Tyndall effect since the red laser has a wavelength around 660 nm, presenting a prismatic structure [27] and showing that the growth of HA/β-TCP crystals successfully occurred on the surface of the cellulosic material. It is observed that there is a relation between the hydrolyzing time and growth of the crystals, with a greater amount of time resulting in a greater quantity of crystals.…”
The use of lignocellulosic remnants of the açaí agro-business will benefit the environment with a precursor material for biomedical applications. Nanocellulose (NC) allows the biomimetic growth of biphasic ceramics on its surface, with characteristics compatible with bone tissue, including bioactive properties and biocompatibility. In this study, the composites were obtained from açaí tegument (Euterpe Oleracea Mart.) NC using acid hydrolysis. The characterization performed by scanning electron microscopy showed the characteristic crystals of hydroxyapatite (HA) and calcium triphosphate (β-TCP) based on the results of X-ray diffraction, with the peak at 22°, showing the NC nucleation of HA and peak at 17° showing tricalcium phosphate (β-TCP). Fourier transform infrared spectroscopy confirmed the presence of O-H at 3400 cm−1 and C-H at 2900 cm−1, which is characteristic of cellulose; peaks were also observed at 1609 cm−1, verifying the reduction in lignin content. Groups PO4−3 at approximately 1070 cm−1, P-OH at 910–1040 cm−1, and HCO3− at 2450 cm−1 confirmed the formation of HA and β-TCP. The zeta potential had a range of −11 ± 23.8 mV related to particle size, which had a range of 164.2 × 10−9–4748 × 10−9 m.
“…2 . Anisotropy in hydroxyapatite crystal growth was observed by others and may results from hydrothermal process condition 30 , 31 . Figure 4 XRD patterns of precipitates obtained from calcium phosphate solutions with ( a ) pH = 4.0 and ( b ) pH ranging from pH = 6.0 to pH = 11.0.…”
Calcium phosphates offer outstanding biological adaptability. Thanks to their specific physico-chemical properties they are one of the most widely used materials in bone tissue engineering applications. The search for an innovative and economic strategy of synthesizing their different forms has been drawing considerable attention in the field. Herein, we report on a facile hydrothermal process in the presence of ethylenediamine tetraacetic acid and monoethanolamine to obtain various forms of calcium phosphates. The monoethanolamine served as an alkaline source and crystal growth modifier, while ethylenediamine tetraacetic acid was used to control the Ca2+ supersaturation level under high temperature and high pressure conditions. The obtained inorganic compounds were examined for their elemental composition, morphology, and structure using scanning electron microscopy, Raman spectroscopy, and powder x-ray diffraction. We were able to selectively synthesize monetite plate-like microcrystals as well as hydroxyapatite plates and nanofibers by simply varying the concentration of monoethanolamine.
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