Hydroxyapatite Particle Size Research Articles

Influence of Hydroxyapatite Particle Size on the Flowability of PLA/HA Filament

Advanced bioactive ceramic materials, Hydroxyapatite (HA) and Polylactic Acid (PLA) are common in bone regeneration implants. As demand for customised implant products increases, research increasingly focuses on developing composite filament manufacturing technology. However, creating PLA/HA composite filament faces challenges, including clumping HA particles and uneven flowability. The brittleness of the filament properties makes it unsuitable for Fused Deposition Modelling (FDM) printing, causing inconsistent extrusion and reduced filament strength. The purpose of this study is to compare the effectiveness of microHAs (m-HAs) and nanoHAs (n-HAs) in the production of filament composite fibers, based on the flowability assessment. The particle size of the micro-HA was reduced to nano by a ball mill process using 4 mL ethanol and the ball-powder ratio of 5:1, which was verified by the particle size analyzer. The feedstock comprises 79.5 wt.% PLA, 19.5 wt.% HA and 1 wt.% impact modifier (IMK) was mixed and rheological tested (130 ℃ to 150 ℃, shear rate: 20-1000 s-1) to achieve pseudoplastic behaviour (n<1). The rheological tests showed that both feedstocks exhibited pseudoplastic behaviour (n<1) across all temperatures studied. The properties of the feedstock were observed by scanning electron microscopy (SEM), and tensile tests evaluated the filament strength. The investigation found that nano-sized HA filament has 24% higher strength than micro-sized PLA/HA filament.

Fabrication of biomimetic scaffold through hybrid forming technique

AbstractBone tissue engineering procedures require the use of a scaffold with a sufficiently porous structure, which serves as a three‐dimensional template for cell attachment, followed by tissue regeneration and vascularization both in vitro and in vivo. This study aimed to create scaffold material with a unique hybrid forming that met these parameters. Slip casting and freeze‐drying processes were used with a hybrid forming approach to create a bone scaffold based on hydroxyapatite (HA) mimicking the structure of cortical and cancellous bones, respectively. HA was synthesized by the wet chemical precipitation method. Fourier‐transform infrared spectroscopy, dynamic light scattering, X‐ray diffraction, thermogravimetric analysis‐differential thermal analysis, Brunauer‐Emmett‐Teller, He Pycnometer, and scanning electron microscope analyses were performed to characterize the scaffold. According to analysis results, HA particle size was found at 137.8 nm. The optimum sintering temperature was determined to be 1300°C. The specific surface area of the HA powder was measured as 55.11 m2/g. The total open porosity of the hybrid scaffold was calculated as 70%. Scaffold successfully substituted both cancellous and cortical layers of bone regarding structural characteristics, porosity, and mechanical strength. Considering morphological characteristics, a hybrid scaffold might facilitate vascularization, osteoinduction, and osteoconduction. Research findings suggest that the hybrid design strongly resembled natural bone and is suitable for both load‐bearing and non‐bearing bones.

Cheminformatics-Based Design and Synthesis of Hydroxyapatite/Collagen Nanocomposites for Biomedical Applications.

This paper presents a novel cheminformatics approach for the design and synthesis of hydroxyapatite/collagen nanocomposites, which have potential biomedical applications in tissue engineering, drug delivery, and orthopedic and dental implants. The nanocomposites are synthesized by the co-precipitation method with different ratios of hydroxyapatite and collagen. Their mechanical, biological, and degradation properties are analyzed using various experimental and computational techniques. Attenuated total reflection-Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction unveil the low crystallinity and nanoscale particle size of hydroxyapatite (22.62 nm) and hydroxyapatite/collagen composites (14.81 nm). These findings are substantiated by scanning electron microscopy with energy-dispersive X-ray spectroscopy, confirming the Ca/P ratio between 1.65 and 1.53 and attesting to the formation of non-stoichiometric apatites in all samples, further validated by molecular simulation. The antimicrobial activity of the nanocomposites is evaluated in vitro against several bacterial and fungal strains, demonstrating their medical potential. Additionally, in silico analyses are performed to predict the absorption, distribution, metabolism, and excretion properties and the bioavailability of the collagen samples. This study paves the way for the development of novel biomaterials using chemoinformatics tools and methods, facilitating the optimization of design and synthesis parameters, as well as the prediction of biological outcomes. Future research directions should encompass the investigation of in vivo biocompatibility and bioactivity of the nanocomposites, while exploring further applications and functionalities of these innovative materials.

Hydroxyapatite particle shape affects screw attachment in cancellous bone when augmented with hydroxyapatite-containing hydrogels

Screw-bone construct failures are a true challenge in orthopaedic implant fixation, particularly in poor quality bone. Whilst augmentation with bone cement can improve the primary stability of screws, there are cements, e.g. PMMA, that may impede blood flow and nutrients and hamper bone remodelling. In this study, soft, non-setting biomaterials based on Hyalectin gels and hydroxyapatite (HA) particles with different morphological parameters were evaluated as potential augmentation materials, using a lapine ex vivo bone model. The pull-out force, stiffness, and work to fracture were considered in evaluating screw attachment. The pull-out force of constructs reinforced with Hyalectin containing irregularly shaped nano-HA and spherically shaped micro-HA particles were found to be significantly higher than the control group (no augmentation material). The pull-out stiffness increased for the micro-HA particles and the work to fracture increased for the irregular nano-HA particles. However, there were no significant augmentation effect found for the spherical shaped nano-HA particles. In conclusion, injectable Hyalectin gel loaded with hydroxyapatite particles was found to have a potentially positive effect on the primary stability of screws in trabecular bone, depending on the HA particle shape and size.

Performance of electrochemically deposited hydroxyapatite on textured 316L SS for applications in biomedicine

ABSTRACT This study investigates the biocompatibility of laser-textured 316L stainless steel (SS) coated with hydroxyapatite (HA) for orthopaedic implants. Powdered HA was electrochemically deposited on the laser-textured surface of 316L SS, and various tests were conducted on its surface to assess its biocompatibility. A particle size analyser was used to determine the average HA particle size, and a 3D optical profilometer was employed to characterise the surface roughness of the laser-textured samples. Contact angle measurement results provide insights into the wettability of the substrate. Microscopy tests revealed that, compared to those without HA coating, HA coatings on spherical dimpled textures exhibited better cell adherence. Among the tested samples, a sample with 98% laser energy input, 40.45° contact angle, and 75.976 µm HA coating thickness was found to be the most suitable for bone implantation.

Effect of hydroxyapatite particle morphology on as-spun poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/hydroxyapatite composite fibers

Hydroxyapatite (HA) has shown very promising results in hard tissue engineering because of its similarity to bone and hence the capability to promote osteogenic differentiation. While the bioactivity of HA is uncontested, there are still uncertainties about the most suitable hydroxyapatite particle shapes and sizes for textile scaffolds. This study investigates the influence of the shape and size of HA particles on as spun fibers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and HA, their mechanical and thermal properties as well as their influence on the fiber degradation in simulated blood matrix and their capability to mineralize in simulated body fluid. The key findings were that the different HA particles’ size does not affect the melting temperature and still maintains a thermal stability suitable for fiber production. Tensile testing revealed decreased mechanical properties for PHBV/HA as spun fibers, independently of the particle morphology. However, HA particles with 30 nm in width and 100 nm in length at 1 wt% HA loading achieved the highest tenacity and elongation at break amongst all composite fibers with HA. Besides, the Ca/P ratio of their mineralization in simulated body fluid is the closest to the one of mineralized human bone, indicating the most promising bioactivity results of all HA particles studied.

Processing of hydroxyapatite (HA)–Ti–6Al–4V composite powders via laser powder bed fusion (LPBF): effect of HA particle size and content on the microstructure and mechanical properties

This research study examines the influence of hydroxyapatite (HA) powder particle size and content on the processability, microstructure, and mechanical properties of the laser powder bed fusion (LPBF) fabricated Ti–6Al–4V (Ti64)-HA composites. For this purpose, various Ti64-HA composite powders were produced, and the effects of the HA particle size and content on the optical reflectance were investigated. Composite powders and the monolithic Ti64 powder (as the reference) were subjected to the LPBF process within a wide range of volumetric energy densities by varying the LPBF process parameters. Parts with the highest relative density for each material were assessed by studying their microstructure, nanohardness, and nanoindentation-derived yield strength. Results revealed that the incorporation of the highly reflective HA powder into the Ti64 slightly enhanced the reflectance of Ti64-HA composite powders over that of the monolithic Ti64 powder. The LPBF processability of the composite powders was found to highly depend on the content of the HA constituent. For any given volumetric energy density employed in this study, composites containing 1 wt%HA were crack-free. However, composite systems containing higher HA content (2.5 wt%) featured randomly distributed transgranular cracks. Addition of 1 and 2.5 wt%HA to the Ti64 resulted in a significant improvement in the nanohardness (∼30 and 75%) and yield strength (∼20 and 37%). The dominant strengthening mechanisms in composite samples were the Hall-Petch and geometrically necessary dislocations strengthening, accounting for 57–66% and 13–20% of the total yield strength improvement.

Macrophage metabolic profile is altered by hydroxyapatite particle size.

Since the recent observation that immune cells undergo metabolic reprogramming upon activation, there has been immense research in this area to not only understand the basis of such changes, but also to exploit metabolic rewiring for therapeutic benefit. In a resting state, macrophages preferentially utilise oxidative phosphorylation to generate energy; however, in the presence of immune cell activators, glycolytic genes are upregulated, and energy is generated through glycolysis. This facilitates the rapid production of biosynthetic intermediates and a pro-inflammatory macrophage phenotype. While this is essential to mount responses to infectious agents, more evidence is accumulating linking dysregulated metabolism to inappropriate immune responses. Given that certain biomaterials are known to promote an inflammatory macrophage phenotype, this prompted us to investigate if biomaterial particulates can impact on macrophage metabolism. Using micron and nano sized hydroxyapatite (HA), we demonstrate for the first time that these biomaterials can indeed drive changes in metabolism, and that this occurs in a size-dependent manner. We show that micronHA, but not nanoHA, particles upregulate surrogate markets of glycolysis including the glucose transporter (GLUT1), hexokinase 2 (HK2), GAPDH, and PKM2. Furthermore, we demonstrate that micronHA alters mitochondrial morphology and promotes a bioenergetic shift to favour glycolysis. Finally, we demonstrate that glycolytic gene expression is dependent on particle uptake and that targeting glycolysis attenuates the pro-inflammatory profile of micronHA-treated macrophages. These results not only further our understanding of biomaterial-based macrophage activation, but also implicate immunometabolism as a new area for consideration in intelligent biomaterial design and therapeutic targeting. STATEMENT OF SIGNIFICANCE: Several recent studies have reported that immune cell activation occurs concurrently with metabolic reprogramming. Furthermore, metabolic reprogramming of innate immune cells plays a prominent role in determining cellular phenotype and function. In this study we demonstrate that hydroxyapatite particle size alters macrophage metabolism, in turn driving their functional phenotype. Specifically, the pro-inflammatory phenotype promoted by micron-sized HA-particles is accompanied by changes in mitochondrial dynamics and a bioenergetic shift favouring glycolysis. This effect is not seen with nano-HA particles and can be attenuated upon inhibition of glycolysis. This study therefore not only identifies immunometabolism as a useful tool for characterising the immune response to biomaterials, but also highlights immunometabolism as a targetable aspect of the host response for therapeutic benefit.

Preparation of Hydroxyapatite from Buffalo Bone and its Biodegradable Nanocomposite with Poly(Butylene Adipate‐co‐Terephthalate)

AbstractIs report, the extraction process for highly nanocrystalline hydroxyapatite (HAp) by thermal decomposition of the femur bone of buffalo and its utilization as filler to produce nanocomposite with poly(butylene adipate‐co‐terephthalate) (PBAT). Advanced analytical techniques (such as X‐ray diffraction [XRD], Fourier transform infrared [FTIR] spectroscopy, and scanning electron microscopy [SEM]) are employed to study the structural, chemical, and morphological properties of the HAp. The XRD analyses reveal that the crystallite size of HAp particles significantly increases from 10 (at 600 °C) to 40 nm (at 1100 °C) on increasing the calcination temperature. The formation of agglomerates (having diameters ranging from 1.75 to 2.72 µm) with thin flake‐like crystals of the HAp is revealed by the SEM analysis. The biodegradation properties of the 3D printed PBAT/HAp nanocomposites are investigated by water absorption and tris‐buffer tests. The extent of water absorption of the nanocomposites is found to increase with the amount of the nanofiller.

Periplasmic space is the key location for Pb(II) biomineralization by Burkholderia cepacia.

Phosphate solubilizing bacteria (PSB) induced phosphate precipitation is considered as an effective method for Pb(II) removal through the formation of stable Pb(II)-phosphate compound, but the location of end-products is still unclear. Herein, the PSB strain of Burkholderia cepacia (B. cepacia) coupled with the hydroxyapatite (HAP) was used in this study to investigate the Pb(II) removal mechanism and the biomineralization location. The dissolving phosphate of three particle sizes of HAP and Pb(II) resistant capabilities, and the effect factors such as HAP dosage, initial concentrations of Pb(II), pH, temperature, and different treatments were determined. The results indicated that the highest soluble phosphate could reach 224.85mg/L in a 200nm HAP medium and the highest removal efficiency of Pb(II) was about 96.32%. Additionally, it was interesting that Pb(II) was mainly located in the periplasmic space through the cellular distribution experiment, which was further demonstrated by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Besides, the characterization results showed that the functional groups such as amide, hydroxy, carboxy and phosphate played an important role in Pb(II) biomineralization, and the free Pb(II) in aqueous solution could be transformed into pyromorphite through phosphate dissolution, extracellular adsorption/complexation, and intracellular precipitation.

Mechanical processing of hydroxyapatite through sintering and multi-objective optimization technique for biomedical application

Hydroxyapatite (HAp) has been widely applied in the area of tissue engineering, however, its poor mechanical properties limit it in load bearing biomedical application. To improve the mechanical integrity of HAp, this study reports the synthesis, optimization and the significance of processing parameters on the physic-mechanical properties of HAp. The HAp was produced from biogenic source through at 900 °C. The L9 Taguchi orthogonal array was employed, considering two processing parameters namely, HAp particle size (100, 300, and 600 mathrm{mu m}) and compaction load (3, 6, and 9 KN). The raw bones (RB) and the synthesized HAp were characterized for phase structure and functional groups analysis. The analysis showed the characteristics of a typical calcium phosphate material. The multiple response optimization revealed that 600 mathrm{mu m} particle size 6 KN compaction load are the optimal processing parameters in the manufacturing of high biomedical performance HAp.Graphical

Effects of the doping concentration of boron on physicochemical, mechanical, and biological properties of hydroxyapatite

Ion doping is an approach to modify properties of materials, like hydroxyapatite (HA), that contributes to designing biomaterials with desired characteristics applicable in bone defect treatments. Recently, boron (B) has been noticed in biomaterial fields due to its beneficial effects on formation, growth, and quality of bone. In this study, B-doped HA nanoparticles with different molar concentrations of B (0.05, 0.1, 0.25, and 0.5) were synthesized through microwave-assisted wet precipitation. The effects of B content on various properties of HA were evaluated. The results demonstrated that the size of HA particles reduced from 106 nm to 89-85 nm in B doped materials. Meanwhile, the crystallinity degree of B doped HA (BHA) samples was between 89.90% and 93.77%, compared to 95.19% of HA. Diametral tensile strength of samples was measured in the ranges of 2.51 and 3.61 with no significant difference among groups. The micro-hardness of HA was 0.88 GPa, whilst doped ones had hardness values of 0.5 GPa–0.68 GPa. Biodegradability of samples increased from less than 1% to approximately 4% after 28 days, while B-doping did not make any change in the degradation rate. Doping dosages were appropriate in terms of bioactivity and cell viability, and B doping caused higher bioactivity and cell proliferation. All changed properties were dose-dependent and more effective in doped groups with a higher amount of B. Despite proliferative effect, 260 μg/l and 770 μg/l of B release in two groups with the highest dopant concentrations did not positively influence the osteogenic activity of cells. Our results demonstrated that doping concentrations that resulted in B release ≤260 μg/l seem more appropriate dosage, especially for bone tissue engineering and substitute applications due to promoted bioactivity and proliferation, as well as no obstructive effects on mechanical properties and osteogenic activities of HA.

Macrophage Metabolic Profile is Altered by Hydroxyapatite Particle Size

Macrophage Metabolic Profile is Altered by Hydroxyapatite Particle Size

Effects of particle size of hydroxyapatite on mechanical property and cytocompatibility of hydroxyapatite/poly(amino acid) composites

AbstractIn this work, three different particle sizes of hydroxyapatites (HA) were synthesized, and these three types of HA were combined with poly(amino acid) (PAA) to form composites (PAA/HA) by phase separation technique. XRD, FT‐IR, SEM, EDS, and XPS analyses were utilized to characterize the structure and morphology of the synthesized three HA particles and composites. Results revealed that HAs with three different particle sizes (short rod (HA1), long rod in nanoscale (HA2), and long rod in micron level (HA3)) were successfully prepared and there was an interface interaction between PAA and HA in composites. Mechanical tests showed that the difference of HA in size played an important role in mechanical performance of the composites. Furthermore, the long rod nano‐HA showed the highest enhancement in flexural yield strength at 81.3% for PAA/HA2 compared with pure PAA. After 28 days of immersion in PBS, PAA, and its composites showed good stability, and the mechanical performance of all composites were remained unchanged. The cell culture results showed all composites were cytocompatible, cells attached on the materials well with excellent morphology. Thus, it could be concluded that particle size influenced mechanical properties of PAA/HA composites, without impacting their cytocompatibility and degradation behavior.

Effect of particle size, shape, and weight percentage of hydroxyapatite (HA) on rheological behaviour of polycaprolactone/hydroxyapatite (PCL/HA) composites

The aim of this study is to investigate the influence of hydroxyapatite’s (HA) particle size, shape, and variation of HA weight percentage on the rheological behaviour of polycaprolactone/hydroxyapatite (PCL/HA) composite. The composite was produced by melt blending process using a single screw extruder assisted with an ultrasonic wave with varied HA weight content (0 wt.%, 10 wt.%, 20 wt.%, 30 wt.% and 40 wt.%). Two types of HA were used, which are needle shape (HAN) and irregular shape (HAS). The rheological behaviour of the PCL/HA composite was investigated through the melt flow index (MFI) test at a varied temperature of 100, 110, and 120 °C. The result indicated that an increase of HA content decreases the MFI values of the PCL/HA composite. At similar content of HA, PCL/HAN composite has higher activation energy with lower MFI values compared to PCL/HAS composite. In conclusion, this study concluded that the particle size, shape, and weight percentage of HA significantly affect the rheological behaviour of PCL/HA composites.

Effects of Different Particle Sizes of Hydroxyapatite on the Distribution and Migration of Trace Elements (Copper and Cadmium) in a Smelter-Impacted Soil.

To study the remediation effect of hydroxyapatite with different particle sizes, a field in situ experiment was carried out by adding conventional hydroxyapatite (0.25 mm) and microhydroxyapatite (3 μm) and nanohydroxyapatite (40 nm) to the contaminated soil and planting Elsholtzia splendens. The distribution and migration of copper (Cu) and cadmium (Cd) in soil were investigated after 4 years. The results show that the application of three different particle sizes of hydroxyapatite significantly raise the soil pH, total phosphorus, and soil organic carbon. Moreover, the addition of hydroxyapatite can reduce the EXC fraction of Cu and Cd by 73.7%–80.1% and 20.8%–35.2%, respectively. In addition, the concentrations of Cu and Cd in >2 mm, 0.25–2 mm, 0.053–0.25 mm, and <0.053 mm aggregate are significantly increased. This improvement indicates that there are risks which may cause the increasing of total Cu and Cd in the soil where the pollution sources still exist. Furthermore, the content of soil colloid is significantly increased, and the colloidal Cu and Cd distribution percentage have been significantly increased by 49.9%–120% and 30.3%–181%. This result illustrates that the application of hydroxyapatite may greatly increase the possibility of colloid and dust migration of Cu and Cd.

Influence of calcination temperature in synthesizing eggshell-derived calcium phosphate

Hydroxyapatite (HA) has been used in the biomedical field not only due to its structural resemblance to the natural bone but also for its being bioactive and thermodynamically stable in the body fluid. Generally, the synthesis of HA particles through various available methods has been directed in controlling the growth of HA particles size as this characteristic has an implicit effect on the mechanical properties, biocompatibility and biological activity of HA in the application. Raw materials for the synthesis of HA can be obtained from commercial chemicals and natural sources. Natural source, particularly eggshell has been favoured due to the presence of other elements inherent in the eggshell that induced better cell response. In this study, a direct solid-state method was used to synthesize HA powder utilizing a Ca source in carbonated form from calcined discarded eggshells. The milled mixture of calcined eggshell powder and phosphorus precursor was subjected to heat treatment at various temperatures in studying the influence of different calcination temperatures on the HA phase stability, particle size and morphology through X-Ray Diffractometer and Scanning Electron Microscope analysis. Overall, HA powder consisted of flower-like particles was successfully obtained from eggshell through the combination of dry powder mixing and heat treatment at 800 °C.

Fabrication of mechanically enhanced hydroxyapatite scaffold with the assistance of numerical analysis

Hydroxyapatite (HAp) has been found to be incompetent as it relates to its mechanical integrity, which somewhat restricts its use for load-bearing clinical applications. Several studies have been conducted doping HAp with foreign elements in order to enhance its mechanical integrity. However, it has been established that foreign elements usually trade off the phase structure and biological integrity of HAp. To avoid this challenge, this study presents a numerical analysis with the aim to fabricate a pure HAp scaffold with high mechanical strength, considering compaction and sintering protocols. The X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy of raw bovine bones (RB) and HAp sintered at 900, 1000, and 1100 °C showed calcium phosphate contents of the bulk materials. It was also observed that increase in sintering temperature made prominent characteristic peaks of HAp phase to become narrower on the XRD patterns. The scanning electron microscope (SEM) analysis on the powdery samples showed that sintering temperature reduced HAp particle size, which resulted to the enhancement noticed in the mechanical properties of the fabricated HAp. Taguchi design analysis on the individual hardness and compressive strength revealed 1100 °C as the optimal sintering temperature, but a disparity in compaction load displaying 5 KN for high hardness and 15 KN for high compressive strength. Conversely, Taguchi grey relational analysis gave common optimal settings for high hardness and compressive strength to fabricate mechanically enhanced HAp scaffold, and are 1100 °C sintering temperature and 5 KN compaction load. Significantly, this study revealed that compaction load has a very high percentage of contribution of 90.15% compared to sintering temperature having a contribution of 7.79%. Confirmation analysis also proved that the experimental grey relational grade of 0.7824 is within 95% confidence interval.

Effect of hydroxyapatite content and particle size on the mechanical behaviors and osteogenesis in vitro of polyetheretherketone–hydroxyapatite composite

AbstractPoly‐ether‐ether‐ketone (PEEK) possesses excellent biocompatibility and similar elastic modulus as bones but suffers from poor osseointegration; usually, the addition of hydroxyapatite (HA) is considered as an effective way to improve the osseointegration of PEEK implant interface. To investigate the effect of HA content and particle size on the mechanical behaviors and osteogenesis in vitro of PEEK‐HA composites, the PEEK‐HA specimens with variable HA content and particle size have been fabricated by powder mixing‐heat press method and characterized by mechanical and biological tests. The results showed that the tensile/bending strength and elongation at break of PEEK‐HA are significantly impaired as the increasing HA amount, but the modulus improves. The compressive strength and modulus are improved as the increasing amount of HA. The PEEK‐HA with smaller HA particle size possesses higher‐performance tensile/bending and lower‐performance compressive properties. In osteogenesis tests in vitro, the results reveal that the cells amount attached on the substrate rises and the cells flatten more evenly with numerous cytoplasmic processes on greater area with the increasing HA content and decreasing particle size. The PEEK‐HA group that HA content is 20 wt% and particle size is 20 nm exhibits optimal‐performance osteogenesis in vitro, while maintaining sufficient mechanical properties.

Phosphorus Bioavailability and Migration of Hydroxyapatite in Different Sizes as Phosphorus Fertilizer in Camellia Oleifera Seedlings

Low mobility and solubility reduce the availability of traditional phosphorus (P) fertilizer in red acidic soil. Hydroxyapatite (HAP), especially nano-hydroxyapatite (n-HAP), may be more efficient than P fertilizer because of its nanoparticle characteristics. Camellia oleifera (C. oleifera) is an edible oil tree whose productivity is greatly affected by P fertilizer. During this study, we investigated the migration of different particle sizes of HAP (20 nm, 200 nm, and 80 μm) and their effects on the seedling growth of C. oleifera cultivar Huashuo (HS) cuttings. A column experiment showed that the efflux ratio was negatively correlated with particle size in red acidic soil. The leaching results revealed that the contents of total P and available P in the 20-nm treatment were significantly higher than those in the 200-nm and 80-μm treatments in the deep soil (10–15 cm or 15–20 cm), whereas the application of 20-nm n-HAP caused 13.43% wastage of available P. During the container experiments, 200-nm and 20-nm HAP significantly promoted the growth of the seedlings in terms of seedling height, stem diameter, and biomass. The available P contents in the rhizosphere and nonrhizosphere soils were negatively correlated with the HAP particle sizes. In conclusion, the migration of HAP is inversely correlated with particle size, and HAP improves the P bioavailability in red acidic soil. In summary, 200-nm HAP was the best P fertilizer for the seedlings of HS among the three particle sizes. This study offers preliminary results indicating that 200-nm HAP might be a better P fertilizer compared with other two HAP particle sizes for use in future C. oleifera orchards.