Hydroxyapatite Nanocomposites Research Articles

Poly(styrene-co-methyl methacrylate)-silver/reduced graphene oxide-nano hydroxyapatite nanocomposites for bone cement applications

Herein, we report (polystyrene-co-polymethylmethacrylate/silver/reduced graphene oxide)-(nano-hydroxyapatite) ((PS-PMMA/Ag/RGO)-(nHA)) nanocomposites as potential bone cement. The polymer nanocomposites were characterized using Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nano-indentation, thermal, and electron microscopic methods. The FT-IR and XRD results confirmed the successful formation of the nanocomposites. The elastic modulus (E) was found to be 6.85 GPa, and hardness (H) was 0.181 GPa for the nanocomposite bone cement samples, while the E and H values of commercial counterparts are 7.22 and 0.218 GPa, respectively. The thermogravimetric analysis (TGA) has revealed that the nanocomposite bone cement are stable up to 371 °C. The addition of nHA enhances the biocompatibility of bone cement. Cytotoxicity studies were conducted using human osteosarcoma MG63 cell lines. In-vitro studies showed that the material does not display any toxicity on the MG63 cell line, and increased concentration of nHA did not significantly impact the material’s toxicity, only impacting the curing kinetics of the cement.

Biogenic magnetic nanocomposite of hydroxyapatite and dextran: synthesis, characterization, and enhanced removal of 2,4-D from aqueous environment.

In this study, a biogenic magnetic nanocomposite, HAP@DEX@MNP, using hydroxyapatite from eggshell waste and dextran was developed to efficiently remove 2,4-D from aqueous solutions. The magnetic nano biocomposite underwent rigorous characterization using a comprehensive suite of analytical techniques, including FTIR, XRD, FESEM, EDX, TEM, and VSM. FTIR analysis was used to validate the existence of pivotal functional groups, such as phosphate, carbonyl, hydroxyl, and iron oxide. XRD analysis verified both the crystalline nature of hydroxyapatite and the successful integration of dextran and hematite within the composite structure. FESEM and EDX examinations provided valuable insights into the surface morphology and elemental composition. TEM observations elucidated the existence of nano-sized particles underscoring the unique structural characteristics of the nanocomposite. Batch adsorption experiments were conducted under optimized conditions, highlighting the critical role of pH 2 for efficient 2,4-D removal. The mechanisms driving the binding of 2,4-D to HAP@DEX@MNP were found to encompass diverse interactions, encompassing electrostatic forces, hydrogen bonding, π-π interactions, and van der Waals forces. Adsorption isotherm studies revealed both monolayer and multilayer adsorption, with the Langmuir and Freundlich models fitting well, indicating a maximal adsorption capacity of 217.39µg/g at 25°C. Kinetic investigations supported the pseudo-second-order model for efficient adsorption dynamics, and thermodynamic analysis emphasized the versatility of HAP@DEX@MNP across different temperatures. Importantly, the study highlighted the remarkable regenerative capacity of the nanocomposite using a 0.1M NaOH solution, positioning it as an environmentally friendly option for water treatment. In conclusion, HAP@DEX@MNP holds significant potential for diverse applications in addressing global water treatment and environmental challenges.

Exploring the physicochemical traits, antifungal capabilities, and 3D spatial complexity of hydroxyapatite with Ag+[sbnd]Mg2+ substitution in the biocomposite thin films

The silver/magnesium doped hydroxyapatite (AgMgHAp, Ca10−x-yAgxMgy(PO4)6(OH)2, xAg=0.05 and yMg=0.02) nanocomposites coatings were deposited on Si substrate using the dip coating technique. The resulting coatings were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR-ATR) spectroscopy, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The EDS analysis highlighted the presence of the constitutive elements of the silver/magnesium doped hydroxyapatite (AgMgHAp) nanocomposites coatings. The surface microtexture of the AgMgHAp was assessed by atomic force microscopy (AFM) technique. The AFM data suggested the obtaining of a uniform deposited layer comprised of equally distributed nanoconglomerates. FT-IR studies highlighted the presence of vibrational modes associated with the phosphate and hydroxyl groups. No bands associated with silver or magnesium were observed. The XPS analysis highlighted the presence of the constituent elements of hydroxyapatite (Ca 2p, P 2 s, O 1 s), as well as dopants (Ag 3d, Mg 1 s and Mg 2p). The antifungal evaluation of AgMgHAp coatings was carried out using the Candida albicans ATCC 10231 fungal strain. The results of the antifungal assay revealed that the AgMgHAp coatings exhibited a strong inhibitory antifungal activity. Furthermore, the data highlighted that the AgMgHAp inhibited the development of biofilm on their surface. The results revealed that the antifungal activity of the coating varied based on the duration of incubation. On the other hand, the data also showed that AgMgHAp nanocomposites coatings inhibited the fungal cell adhesion and development from the early stages of the incubation. In addition to morphological analysis, we additionally take advantage of AFM images to investigate and explore the domain of fractal and multifractal analysis applied to the films under evaluation. Our studies indicates that nanocomposite coatings made from AgMgHAp demonstrate strong antifungal properties. Our studies indicates that nanocomposite coatings made from AgMgHAp demonstrate strong antifungal properties. These results suggest the potential of AgMgHAp nanocomposite coatings as a promising solution for developing innovative antifungal devices in biomedical applications.

Morphology and biological responses of nanocomposites of hydroxyapatite, graphene oxide, and dysprosium oxide (Dy2O3) for biomedical applications

In this research study, various nanocomposites, namely Dy2O3, Sm2O3, HAP/Dy2O3, HAP/Dy2O3/GO, and HAP/Sm2O3/GO, were extensively examined and analyzed. The primary focus was on the development of advanced biomaterials with improved mechanical properties, biocompatibility, and antimicrobial activity. The investigation involved the use of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques to observe the distinctive nanorods of hydroxyapatite (HAP) within the ternary nanocomposite. The SEM micrographs yielded an average size of 69 ± 22 * 19 ± 4 nm for the HAP nanorods, accompanied by an average roughness measurement of 10.5 nm. The TEM analysis provided further insights into the distribution of HAP and Sm2O3 within graphene oxide (GO) nanosheets, revealing HAP particles measuring 20 nm in size and 65 nm in length, and Sm2O3 particles measuring 6 nm in size. To evaluate the biocompatibility of the newly developed ternary nanocomposite, HAP/Dy2O3/GO, osteoblast cells were employed. The results showed a minor decrease in cell viability, with a measured percentage of cell viability at 97.5 ± 2.1 %. Furthermore, the HAP/Dy2O3/GO nanocomposite exhibited notable antibacterial properties against E. coli and S. aureus bacteria, as indicated by inhibition zones measuring 15.3 ± 0.8 mm and 15.9 ± 1.1 mm, respectively. The unique composition of HAP/Dy2O3/GO demonstrated enhanced roughness parameters and improved biocompatibility due to its altered topological features. Additionally, its remarkable antibacterial activity and robust mechanical strength establish HAP/Dy2O3/GO as a promising candidate for further investigation as a biomaterial for bone implants.

Synthesis of novel magnetic hydroxyapatite-biomass nanocomposite for arsenic and fluoride adsorption.

A magnetic nanocomposite of hydroxyapatite and biomass (HAp-CM) was synthesized through a combined ultrasonic and hydrothermal method, aiming for efficient adsorption of arsenic (As) and fluoride (F-) from drinking water in natural environments. The characterization of HAp-CM was carried out using TG, FTIR, XRD, SEM, SEM-EDS, and TEM techniques, along with the determination of pHpzc charge. FTIR analysis suggested that coordinating links are the main interactions that allow the formation of the nanocomposite. XRD data indicated that the crystalline structure of the constituent materials remained unaffected during the formation of HAp-CM. SEM-EDS analysis revelated a Ca/P molar ratio of 1.78. Adsorption assays conducted in batches demonstrated that As and F- followed a PSO kinetic model. Furthermore, As adsorption fitting well to the Langmuir model, while F- adsorption could be explained by both Langmuir and Freundlich models. The maximum adsorption capacity of HAp-CM was found to be 5.0mgg-1 for As and 10.2mgg-1 for F-. The influence of sorbent dosage, pH, and the presence of coexisting species on adsorption capacity was explored. The pH significantly affected the nanocomposite's efficiency in removing both pollutants. The presence of various coexisting species had different effects on F- removal efficiency, while As adsorption efficiency was generally enhanced, except in the case of PO43-. The competitive adsorption between F- and As on HAp-CM was also examined. The achieved results demonstrate that HAp-CM has great potential for use in a natural environment, particularly in groundwater remediation as a preliminary treatment for water consumption.

Investigations on Microstructure and Mechanical Properties of HAp Nanocomposites reinforced with ZrO2 and TiO2

In the contemporary context, approximately 15 million individuals in India grapple with bone-related issues stemming from accidents, fractures, bone mass depletion, and the natural aging process. To address this challenge, a diverse array of biomaterials has been innovated to rectify or enhance bone deficiencies within the human body. Nevertheless, over the past decade, calcium phosphate-based bioceramic materials have gained significant prominence as synthetic alternatives for bone and dental applications in the fields of orthopaedics and dentistry. One such bioactive ceramic, Hydroxyapatite (HAp), boasts exceptional versatility and can find utility in both dental and orthopaedic contexts. In the current research, exhaustive research was conducted to explore the impact of HAp/(ZrO2+TiO2) hybrid nano-composites synthesized through a mechanical synthesis process employing high-energy ball milling (HEBM), incorporating varying weight proportions. The resulting “HAp/(ZrO2+TiO2) nano-composites” were subjected to characterization through scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD). Furthermore, the study assessed the influence of these nano-composites regarding the HAp nano-composites’ mechanical characteristics.

Simulation of tensile strength for polymer hydroxyapatite nanocomposites by interphase and nanofiller dimensions

AbstractSeveral models have been used in literature studies to describe the mechanical behavior of hydroxyapatite (HA) polymer nanocomposites. However, previous models have often overlooked the size of HA and the properties of the interphase. In this study, we further develop an equation originally proposed by Kolarik. This advanced equation predicts the tensile strength of polymer/HA nanocomposites by considering the interphase parameter (A), rod‐like HA size, HA concentration, and interphase properties, including depth and strength. We validate our method using experimental data from various examples and through parametric inspections. Both the strength and the depth of the interphase directly affect the ‘A’ value and, consequently, the strength of the nanocomposites. For instance, an HA radius (R) of 6 nm yields the highest ‘A’ value of 4.97, enhancing the nanocomposite strength by up to 250%. In contrast, ‘R’ value of 20 nm fails to reinforce the samples effectively. Additionally, the thickness of the interphase (t) and the concentration of HA directly handle the nanocomposite strength. The strength of the samples significantly improves by 137% and 160% with an interphase thickness of 50 nm and an HA volume fraction of 0.2, respectively. Generally, the length of HA and interphase characteristics (thickness and strength) directly control the strength of samples, but the HA radius has an inverse relationship with nanocomposite strength.Highlights Kolarik equation is developed to predict the tensile strength of polymer HA nanocomposites. Interphase parameter, HA size, HA concentration and interphase properties are considered. HA radius of 6 nm produces the maximum enhancement of nanocomposite strength by 250%. Interphase properties and concentration of HA directly control the nanocomposite strength. All parameters reasonably influence the strength of samples confirming the developed model.

Polycaprolactone Microsphere‐Encapsulated Fluconazole‐Loaded Zinc Oxide and Hydroxyapatite Nanocomposites for Enhanced Biological Performance

AbstractOsteomyelitis (OM), a debilitating disease caused by a microbial infection of the bones, continues to pose a formidable obstacle for orthopedic surgeons. The conventional methods for the prevention and treatment of OM are insufficient. In this research work, we developed a strategic green nanostructure using the antifungal drug Fluconazole (FCZ)‐assimilated zinc oxide nanoparticles (ZnO‐NPs) and hydroxyapatite (HAp) nanostructures as filler and hydrophobic polycaprolactone (PCL) as matrix by a solution‐based chemical method. The ceramic carrier‐like nanostructures ZnO and HAp were synthesized by the in situ precipitation method. The physicochemical characterization of the prepared polymer‐coated drug ceramic nanocomposite (FCZ‐ZnO‐HAp‐PCL) was achieved using Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), particle size distribution (PSD), X‐ray diffraction (XRD), and Energy‐dispersive X‐ray (EDX) analysis. Furthermore, the biocompatibility and anticancer activity of the nanocomposite were explored by an MTT assay study. Successfully synthesized FCZ‐ZnO‐HAp‐PCL nanocomposite exhibited profound antimicrobial activity against targeted microbe species and potential cytotoxicity towards MCF‐7 human breast adenocarcinoma cell lines, which may be potentially used for the treatment of OM and prospective infections.

The effect of triglycerol diacrylate on the printability and properties of UV curable, bio-based nanohydroxyapatite composites

3D printable biopolymer nanocomposites composed of hydroxyapatite nanoparticles and functionalized plant-based monomers demonstrate potential as sustainable and structural biomaterials. To increase this potential, their printability and performance must be improved. For extrusion-based 3D printing, such as Direct Ink Writing (DIW), printability is important for print fidelity. In this work, triglycerol diacrylate (TGDA) was added to an acrylated epoxidized soybean oil:polyethylene glycol diacrylate resin to increase hydrogen bonding. Greater hydrogen bonding was hypothesized to improve printability by increasing the ink's shear yield strength, and therefore shape holding after deposition. The effects of this additive on material and mechanical properties were quantified. Increased hydrogen bonding due to TGDA content increased the ink's shear yield stress and viscosity by 916% and 27.6%, respectively. This resulted in improved printability, with best performance at 3 vol% TGDA. This composition achieved an ultimate tensile strength (UTS) of 32.4 ± 2.1 MPa and elastic modulus of 1.15 ± 0.21 GPa. These were increased from the 0 vol% TGDA composite, which had an UTS of 24.8 ± 1.8 MPa and a modulus of 0.88 ± 0.06 GPa. This study demonstrates the development of bio-based additive manufacturing feedstocks for potential uses in sustainable manufacturing, rapid prototyping, and biomaterial applications.

Scrutinizing the effect of rGO-cuttlefish bone hydroxyapatite composite infused carrageenan membrane towards wound reconstruction

Carrageenan is an emerging biopolymer for wound healing and regenerative applications. In this study, reduced graphene oxide (rGO) and hydroxyapatite (HAp) nano-composites infused carrageenan bioactive membrane was fabricated. Here, hydroxyapatite was synthesized from cuttlefish bone (CF-HAp) and its properties were compared with that of chemically synthesized HAp. Crystalline Ca5(PO4)3(OH) and Ca3(PO4)2) phases were obtained in cuttlefish bone derived HAp. Reduced graphene oxide was synthesized and composites were prepared with chemical HAp and CF-HAp. FT-IR spectral analysis showed the imprints of hydroxyapatite on the membrane and also nano-structured particles were evident through morphological estimations that confirm the distribution of nano-particles on the carrageenan membrane. Nano-particulates infused carrageenan membrane showed the maximum tensile strength, in which graphene incorporated carrageenan bioactive membrane showed highest stability of 15.26 MPa. The contact angle of chemical HAp infused carrageenan membrane (CAR-HAp) showed more hydrophilic in nature (48.63° ± 7.47°) compared to control (61.77° ± 1.28°). Bio-compatibility features enunciate the optimal compatibility of fabricated bioactive membrane with fibroblast cell line; simultaneously, CAR-rGO-CF-HAp showed tremendous wound healing behavior with zebrafish model. Hence, fabricated bioactive membrane with the infusion of rGO- hydroxyapatite derived from cuttlefish bone was found to be a versatile biopolymer membrane for wound healing application.

Investigations on anticancer activity of Eu3+ doped hydroxyapatite nanocomposites against MCF7 and 4T1 breast cancer cell lines: A structural and luminescence Perspective

Breast cancer remains a significant global health concern, necessitating the development of novel therapeutic approaches. In this study, we investigate the role of Eu3+ doped hydroxyapatite nanocomposites (Han: Eu3+) in the treatment of MCF7 and 4T1 breast cancer cell lines. Furthermore, we explored the structural and luminescent properties of these nanocomposites. Han: Eu3+ were synthesized using a modified co-precipitation method, and their morphology and crystal structure were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) in which the average crystalline size of Han: Eu3+ was found to be 25 nm, rendering them suitable for cellular uptake and targeted therapy. To gain insights into the luminescent properties of Han: Eu3+, their excitation and emission spectra were recorded using photoluminescence spectrometer. The characteristic red emission of Eu3+ ions was observed upon excitation, validating the successful doping of Eu3+ into the Han lattice, which was confirmed by the CIE chromaticity coordinate study. These luminescent properties of Han: Eu3+ hold promise for potential applications in bioimaging. To evaluate the efficacy of Han: Eu3+ in breast cancer treatment, MCF7 and 4T1 cell lines were exposed to varying concentrations of the nanocomposites. Cell viability assays revealed a concentration-dependent reduction in cell viability, indicating the potential anticancer activity of Han: Eu3+. The findings of this study contribute to the expanding field of nanomedicine, bringing targeted breast cancer treatments and us closer to more effective.

Fabrication of the polyetherketoneketone-reinforced nano-hydroxyapatite composites as inspired by the cortical bone

Cortical bone has superior mechanical performance. Hydroxyapatite (HA) as its main component are attractive bioactive materials, but possess weak strength. The critical factor is the difference in the structure. Inspired by the hierarchical and delicate architecture of the cortical bone, we used a slurry with 2 wt% polyvinyl alcohol (PVA) and 20 vol% polydopamine-modified nano HA (nHA, pDA-nHA) to fabricate stronger scaffolds characterized by a lamellar structure. Additionally, we immersed the pDA-nHA scaffolds into the polyetherketoneketone (PEKK) synthesis system to reinforce the scaffolds. The cortical bone-inspired composites were produced successfully, and the 20 vol% pDA-nHA+2 wt% PVA/PEKK composites had the highest strength and modulus. It provides a new solution for enhancing the mechanical strength of the single component, as well as improving the bioactivity of PEKK.

Hydroxyapatite nanoparticles reinforced polyvinyl alcohol/chitosan blend for optical and energy storage applications

AbstractBiopolymer blend nanocomposite films composed of polyvinyl alcohol (PVA) and chitosan (CS) with varying quantities of hydroxyapatite (HA) nanoparticles were developed using a green solution casting method. The formation of blend nanocomposite was confirmed by Fourier‐transform infrared spectroscopy (FTIR), ultraviolet–visible (UV) spectrometer, field‐emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Mechanical parameters such as tensile strength, percentage elongation at break, hardness, dielectric constant, and temperature‐dependent alternating current (AC) conductivity were analyzed. The bonding between the nanoparticles and PVA/CS blend was verified by the shift in distinctive peaks of blend in the nanocomposites to a higher wavenumber in the FTIR spectra. The UV spectra demonstrated the difference in absorbance and transmittance of the PVA/CS blend with the reinforcement of HA nanofillers. The bandgaps of the nanocomposites marginally decreased with an increase in nanoparticle loading. The SEM and XRD patterns revealed the ordered arrangement of the blend matrix due to the presence of nanoparticles. The assessment of thermal characteristics obtained from DSC and TGA demonstrated a clear increase in phase transition temperature and thermal stability of nanocomposites. The electrical conductivity measurement indicated a rise in dielectric constant and AC conductivity of blend nanocomposites with the addition of nanoparticles. The temperature‐dependent AC conductivity showed a reduction in activation energy as temperature and nanoparticle loading increased. The tensile strength and surface hardness of the PVA/CS blend nanocomposite increased with the dosage of HA content in the blend matrix.Highlights A series of polyvinyl alcohol (PVA)/chitosan (CS)/hydroxyapatite (HA) nanocomposites were prepared by the green method Enhanced optical property, thermal stability, and glass transition temperature Possess excellent dielectric constant and alternating current conductivity The inclusion of HA increased the mechanical strength of the PVA/CS blend A potential blend nanocomposite for flexible optoelectronic and charge storage devices.

Interface engineering of Zn3V2O8 decorated hydroxyapatite nanocomposite for photocatalytic degradation of Congo red dye and anti-microbial applications

Schematic representation of the synthesis of ZnV/HAP composite for the degradation of CR dye and anti-microbial applications.

Nanozyme-based sensing of dopamine using cobalt-doped hydroxyapatite nanocomposite from waste bones.

Dopamine is one of the most important neurotransmitters and plays a crucial role in various neurological, renal, and cardiovascular systems. However, the abnormal levels of dopamine mainly point to Parkinson's, Alzheimer's, cardiovascular diseases, etc. Hydroxyapatite (HAp), owing to its catalytic nature, nanoporous structure, easy synthesis, and biocompatibility, is a promising matrix material. These characteristics make HAp a material of choice for doping metals such as cobalt. The synthesized cobalt-doped hydroxyapatite (Co-HAp) was used as a colorimetric sensing platform for dopamine. The successful synthesis of the platform was confirmed by characterization with FTIR, SEM, EDX, XRD, TGA, etc. The platform demonstrated intrinsic peroxidase-like activity in the presence of H2O2, resulting in the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The proposed sensor detected dopamine in a linear range of 0.9-35μM, a limit of detection of 0.51 µM, limit of quantification of 1.7 µM, and an R2 of 0.993. The optimization of the proposed sensor was done with different parameters, such as the amount of mimic enzyme, H2O2, pH, TMB concentration, and time. The proposed sensor showed the best response at 5mg of the mimic enzyme, pH 5, 12mM TMB, and 8mM H2O2, with a short response time of only 2min. The fabricated platform was successfully applied to detect dopamine in physiological solutions.

Electrospun gelatin-polyvinyl alcohol-silk fibre/hydroxyapatite scaffolds and their physicochemical and biological studies

The present study is focused on the preparation of a gelatin-polyvinyl alcohol (PVA)-silk fibre (SF)/hydroxyapatite (HAP) composite. Here, HAP acted as a reinforcement in the Gelatin-PVA-SF matrix to enhance the mechanical and biological properties. The gelatin-PVA-SF/HAP (10–70 wt% of HAP was added to 10:70:20 of gelatin-PVA-SF) nanocomposite was prepared via the electrospinning method and characterised by XRD, FTIR, and SEM-EDAX techniques. The highest tensile strength (93.81 MPa) was observed for 60 wt% of HAP-added composite. To evaluate the scaffold's suitability for bone tissue engineering applications, antimicrobial activity, hemocompatibility with human blood and bioactivity studies were carried out. The zone of inhibition against the microbes is as follows: E. coli - 52 mm, S. aureus - 48 mm, C. albicans - 42 mm and hemocompatibility assay showed less hemolytic (%) 1.24% for gelatin/PVA/SF with 60 wt% of HAP composite. The results suggest that gelatin/PVA/silk fibre with 60 wt% of HAP nanocomposite could be an effective and potential candidate for bone tissue engineering applications based on the mechanical, antimicrobial activity and apatite formation ability. Cytotoxicity evaluation was carried out using L929 cells (mouse fibroblast cells) for the gelatin/PVA/silk fibre with 60 wt% of HAP nanocomposite.

Optimized synthesis of cysteine-functionalized nanocrystalline hydroxyapatite for synchronous decontamination of Cd(II) and Pb(II)

The synchronous removal of toxic heavy metals (e.g., cadmium (Cd), lead (Pb), and etc.) from the contaminated water environment is an urgent demand in the pollution control field. Herein, an innovative adsorbent synthesis idea was proposed and a series of cysteine-functionalized nanohydroxyapatite (CysHAP) composites were prepared by adopting different reaction temperatures, cysteine/HAP ratios, and synthesis methods. According to the single factor tests, a co-precipitation temperature of 25 °C with a molar cysteine/HAP ratio of 2.0 was selected to synthesize the optimum CysHAP2.0–25 composite. Multiple characterization results showed that cysteine markedly altered the morphology, crystallinity, and crystal structure of HAP, leading to the formation of CysHAP2.0–25 composite with a superior dispersity, a smaller crystal size, a higher specific surface area, and a greater number of binding sites. Compared with HAP-25, the CysHAP2.0–25 composite exhibited a better Cd(II) sorption performance and a 100% Pb(II) removal in a wide range of solution pH and background electrolyte concentration. The removal performance of CysHAP2.0–25 composite towards Cd(II) was suppressed by the coexisting aqueous components with an obviously stronger inhibiting action of humic acid (HA) than low molecular weight organic acids (LMWOAs) and mixed inorganic components (IC). Pb(II) slightly reduced the sorption ratio of Cd(II) and forced Cd(II) to bind on the -SOx sites derived from sulfhydryl oxidation. In contrast, Cd(II) had no impact on the sorption behaviors of Pb(II). Overall, the synthesized CysHAP2.0–25 composite could be potential applied for the purification of Cd- and Pb-bearing water systems.

Fabrication of novel printable artificial bone composites used as cartilage scaffolds by an additive manufacturing process

AbstractPolylactic acid (PLA), a biodegradable polymer, has become a major raw material in the field of 3D printing. However, some defects such as high brittleness and average bioactivity limit its application. In this study, a novel 3D printing composite of animal bone powder/polyethylene glycol/polylactic acid was prepared and investigated. The structures and properties of bHA/PEG/PLA composites were compared with commercial micron‐sized hydroxyapatite (mHA) and nano hydroxyapatite (nHA) composites. The study results show that the bHA has the same chemical structure as mHA and nHA, but its average particle size is 390 nm, which is quite different from mHA and nHA. When the PEG content is 14%, the toughness of the PEG/PLA blends is good, and its elongation at break reaches 96.23%. The bending strength, tensile strength, and elongation at break of bHA/PEG/PLA composites reach 25.1 MPa, 16.3 MPa, and 11.32%, respectively, which are all higher than those of mHA/PEG/PLA and similar to those of nHA/PEG/PLA. The bHA/PEG/PLA biological scaffolds prepared by 3D printing show good biocompatibility in cytotoxicity experiments and have good application prospects in bone tissue engineering.

Development of P(3HB-co-3HHx) nanohydroxyapatite (nHA) composites for scaffolds manufacturing by means of fused deposition modeling

This work reports on the development of nanocomposites based on poly(3- hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] and nanohydroxyapatite (nHA) for the development of scaffolds by means of a two-stage extrusion process followed by a 3D printing process. Tensile test samples were produced for the characterization of the materials. Each processing thermal cycle promoted a slight thermal degradation, identified by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Also, a viscosity reduction was observed in the rheological measurements. The 3D-printed tensile test samples exhibited increasing stiffness at increasing nHA content (with elastic modulus values close to 1000 MPa), while tensile strength and strain at break were reduced. Nonetheless, the deposition direction oriented with the tensile direction (raster angle of 0°C) exhibited the highest tensile strength (18 MPa) but lower elongation at break than the 45°/−45°C deposition, which resulted in the highest strain (up to 17%). Regarding the scaffolds, they were degraded in phosphate-buffered saline at 37°C for 8 weeks. This degradation was identified by a reduction of their weight (between 1.5% and 3.0%) and reduced mechanical behavior measured by means of a compression test. Scaffolds showed a decrease of the compression strength (from values close to 13 MPa to 9 MPa). 

Enhancement of physicochemical characterization of nanocomposites on Ag+/Fe2+ codoped hydroxyapatite for antibacterial and anticancer properties

The synthesis of nanosized Ag+/Fe2+ codoped hydroxyapatite (HAp) nanocomposite materials with antibacterial and anticancer characteristics is highly attractive for advancing the development of biological applications. The objective of this study was to evaluate the antibacterial and anticancer characteristics of Ag+/Fe2+ codoped hydroxyapatite materials. We developed a facile chemical precipitation method for the fabrication of Ag+/Fe2+:HAp nanocomposites. The developed Ag+/Fe2+:HAp nanocomposite materials were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). For measuring the size of Ag+/Fe2+:HAp nanocomposites, dynamic light scattering (DLS) is an advantageous method. The chemical states and chemical composition of Ag+/Fe2+:HAp were observed by X-ray photoelectron spectroscopy (XPS) analysis. In addition, the antibacterial efficacy of Ag+/Fe2+:HAps against Gram-positive (S.aureus), and Gram-negative (S.typhi, and E.Coli) microorganisms is examined in this current study. Ag+/Fe2+:HAp nanocomposite materials have been evaluated for biological toxicity in vitro, and the results showed that the particles were excellent at identifying and killing cancer cells. In this respect, Ag+/Fe2+:HAp nanocomposites significantly impact human colon cancer cells (HT29) while have no effect on normal fibroblast cells (L929).