Nanostructured Hydroxyapatite Research Articles

Preparation of gold/hydroxyapatite hybrids using natural fish scale template and their effective albumin interactions

The gold (Au) nanoparticles (NPs) with the diameter of 15–40 nm were successfully synthesized in the hierarchical hydroxyapatite (HAp) nanostructures of natural fish scale templates, which were carried out by the Au3+ ion chemisorption, reduction and calcination processes to form the AuNPs/HAp hybrids. The AuNPs size as well as the surface plasmon resonance (SPR) absorption maximum was preserved with the hybridization process. Moreover, the AuNPs/HAp hybrid nanostructures exhibited preferential protein adsorption behavior at the biological bovine serum albumin (Ab) concentration regions that correspond to be 1.5 μM in the cell culture medium and 15.1 μM in human blood, and the Ab adsorption equilibrium constant of AuNPs/HAp hybrid was higher than that of the HAp alone. The SPR absorption maxima of the Ab-adsorbed AuNPs/HAp fish scales were red-shifted as compared with those of the AuNPs/HAp fish scales. Therefore, we synthesized the AuNPs using the fish scale template to exhibit the preferential protein adsorption, which will be a great significance to research the AuNPs/HAp hybrid functions.

RNA-Seq investigation and in vivo study the effect of strontium ranelate on ovariectomized rat via the involvement of ROCK1

Strontium ranelate (SrR) is an anti-osteoporosis drug with excellent osteogenic and angiogenic capacity. In this study, we aimed to investigate the osteogenesis and angiogenesis effects of SrR and the underlying mechanism involved. RNA-Seq was conducted to examine the effects of SrR on gene expression in ovariectomy rat bone marrow mesenchymal stem cells (OVX-rBMSCs). To validate the different expressed gene in vitro, the effects of gene interference and overexpression in osteogenic induction environment of OVX-rBMSCs and in primary osteoblasts were studied. RNA-Seq showed that ROCK1 significantly increased after SrR treatment in OVX-rBMSCs, and further validated by real-time PCR and western blotting. Overexpression of ROCK1 promoted osteogenic differentiation of OVX-rBMSCs and induced cell viability and inhibited apoptosis of primary osteoblasts, which was reversed by inhibition of ROCK1 by RNA interference or ROCK1 inhibitor (Y-27632) after SrR treatment. Furthermore, the SrR was loaded on nano-structured hydroxyapatite (nano-HAp) particulates to promote osteogenesis and angiogenesis in repairing of the femoral condyle bone defect using ovariectomy rat model. Taken together, ROCK1 is one of the targets that SrR promotes the osteogenic differentiation of OVX-rBMSCs and cell viability of primary osteoblasts, the nano-HAp particles could act as carriers for SrR to repair bone defects.

Fabrication and characterization of strontium-doped borate-based bioactive glass scaffolds for bone tissue engineering

Boron is an essential element for bone health, but its cytotoxicity depends on its concentration. In the present study, borate-based 13-93B2 glass scaffolds doped with varying amounts of strontium (0-9 mol.% Sr) with a porosity of 80% and pore size of 200–500 μm were prepared by a polymer foam replication technique. The effect of strontium content on the structure and bioactive properties of scaffolds were investigated by FTIR, XRD, ICP and MTT test. The results showed that the appearance of strontium in the glass has no obvious effect on the structure. The as-made scaffolds were amorphous and had a compressive strength of 11 MPa. The scaffolds in vitro bioactivity was observed by the conversion of the glass surface to a nanostructured hydroxyapatite layer in SBF. The increase of strontium concentration in borate-based glass accelerated the release of Si4+, Ca2+ ions, and significantly reduced the release of B3+ ions in some extent. The results indicated that borate-based bioactive glass doped with particular proportion of Sr suppressed the rapid release of boron and the cytotoxicity of glass scaffolds was minimized at least. This strontium-doped borate-based bioactive glass could be a potential scaffold material for bone tissue engineering.

Recent Trends in Hydroxyapatite (HA) Synthesis and the Synthesis Report of Nanostructure HA by Hydrothermal Reaction.

This research summary the trend in synthesis of Hydroxyapatite (HA) using different route such as dry method and wet method (co-precipitation method; emulsion method, hydrolysis method, sol-gel method, hydrothermal method). In addition, the research group also report the technique to synthesis nano-structure HA by hydrothermal reaction using Ca(OH)2 and H3PO4 with the Ca/P molar ratio of 1.67. The mixture after homogenized for 2 h, follow by hydrothermal reaction at different hydrothermal temperature time (100 °C, 150 °C, and 180 °C) and different hydrothermal reaction time (0 h, 12 h and 24 h). The 180 °C-hydrothermal treated-HA has needle-like shape with the diameter of 10 ~ 20 nm and length of below 100 nm, which is similar with human bone. For the hydrothermal reaction, temperature is the key to form nanostructure HA.

Does cationic incorporation into carbonated hydroxyapatite improve bone repair?

Background: Calcium phosphate ceramics are a group of materials that have been widely used in bone regeneration, especially hydroxyapatite (HA), because of its biocompatibility and similarity to the main mineral phase component of bone tissue. However, the biological apatite has nanometric dimensions and cationic and anionic substitutions and presents low crystallinity, which differs from stoichiometric HA. Aims: The ionic substitutions in the composition of HA have been done to mimic biological apatite and improve its physicochemical characteristics. Previous studies have demonstrated that strontium-, magnesium-, zinc-, and iron-isolated substitution stimulate osteoblastic activity, as well as reduce osteoclastic activity. Materials and Methods: This study evaluated the osteogenic potential of nanostructured carbonated hydroxyapatite microspheres (cHAMs) containing 5% strontium, 5% zinc, 5% magnesium, 1% iron, and 5% manganese, after implantation in a critical size defect in the rat's calvaria. Two experimental groups were studied: cHA 37°C (nanostructured cHA, control) and cHAM 37°C (metals doped nanostructured cHA). The animals were euthanized after 1, 3, and 6 months, and the samples were histologically processed for histomorphometric analysis regarding the presence of residual biomaterial, neoformed bone, and connective tissue. Statistical Analysis: The averages found were analyzed statistically by the D'Agostino and Pearson analysis and by Kruskal–Wallis test; significant differences were observed for P

Facile hydrothermal synthesis of antibacterial multi-layered hydroxyapatite nanostructures with superior flexibility

The synthesis of silver-doped multi-layered hydroxyapatite nanobelts is of great importance due to their being a potential candidate to curb the infections associated with HA implants along with their advantage as a reinforcement in biomaterials.

Sol Gel Assisted Microwave Synthesised Hydroxyapatite Nanostructure using Biowaste Musselshell as A Calcium Source

Sol Gel Assisted Microwave Synthesised Hydroxyapatite Nanostructure using Biowaste Musselshell as A Calcium Source

ОПЫТ ПРИМЕНЕНИЯ НОВОЙ ФАРМАКОЛОГИЧЕСКИ АКТИВНОЙ КОМПОЗИЦИИ НАНОСТРУКТУРИРОВАННОГО ФТОРАПАТИТА ПРИ ЛЕЧЕНИИ РАННИХ ПРОЯВЛЕНИЙ ПОВЫШЕННОЙ СТИРАЕМОСТИ ЗУБОВ

Subject. The article presents an investigation of the dental status of patients with early manifestations of tooth wear. The effectiveness of applying a new pharmacologically active composition of nanostructured fluorine hydroxyapatite as a remineralizing agent in the form of a gel in comparison with traditional methods was evaluated. Objectives. To study the effectiveness of a new pharmacologically active composition of nanostructured fluorhydroxyapatite application in the treatment of early manifestations of tooth wear. Methods. 153 patients were examined at the stages of remineralizing therapy with using a new pharmacologically active composition and traditional methods, indexed OHI-S, PMA, KPU, periodontal index, indicators of electrometry, test of enamel resistance, quality of life. Results. Within 1 year of observations in the study groups, in 91.2% cases, a persistent remission of the disease without progression of the loss of hard dental tissues was observed against the background of a decrease in the electrometry and test of enamel resistance test. 56.4% of patients throughout the year noted the absence of a symptom of hyperesthesia. The recurrence of the symptom of hyperesthesia against a background of fixed indices of resistance and electrical conductivity of enamel was noted by 34.8% of patients. In 8,8% of cases there was a lack of dynamics of indices and reduction of hyperesthesia. Conclusions. The level of caries-resistance and electrical conductivity of enamel of the teeth of patients of two groups was studied: with facets of erasability within the enamel and with dotted dentin damage against the background of the course of remineralizing therapy with using pharmacologically active composition of nanostructured fluorine hydroxyapatite. The relationship between the reduction of the symptom of hyperesthesia and the increase in the level of dental health of patients after the end of treatment was revealed.

Recent progress on fabrication and drug delivery applications of nanostructured hydroxyapatite.

Through this brief review, we provide a comprehensive historical background of the development of nanostructured hydroxyapatite (nHAp), and its application potentials for controlled drug delivery, drug conjugation, and other biomedical treatments. Aspects associated with efficient utilization of hydroxyapatite (HAp) nanostructures such as their synthesis, interaction with drug molecules, and other concerns, which need to be resolved before they could be used as a potential drug carrier in body system, are discussed. This review focuses on the evolution of perceptions, practices, and accomplishments in providing improved delivery systems for drugs until date. The pioneering developments that have presaged today's fascinating state of the art drug delivery systems based on HAp and HAp-based composite nanostructures are also discussed. Special emphasis has been given to describe the application and effectiveness of modified HAp as drug carrier agent for different diseases such as bone-related disorders, carriers for antibiotics, anti-inflammatory, carcinogenic drugs, medical imaging, and protein delivery agents. As only a very few published works made comprehensive evaluation of HAp nanostructures for drug delivery applications, we try to cover the three major areas: concepts, practices and achievements, and applications, which have been consolidated and patented for their practical usage. The review covers a broad spectrum of nHAp and HAp modified inorganic drug carriers, emphasizing some of their specific aspects those needed to be considered for future drug delivery applications. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease Nanotechnology Approaches to Biology > Cells at the Nanoscale.

Effects of atomic-level nano-structured hydroxyapatite on adsorption of bone morphogenetic protein-7 and its derived peptide by computer simulation

Hydroxyapatite (HA) is the principal inorganic component of bones and teeth and has been widely used as a bone repair material because of its good biocompatibility and bioactivity. Understanding the interactions between proteins and HA is crucial for designing biomaterials for bone regeneration. In this study, we evaluated the effects of atomic-level nano-structured HA (110) surfaces on the adsorption of bone morphogenetic protein-7 (BMP-7) and its derived peptide (KQLNALSVLYFDD) using molecular dynamics and density functional theory methods. The results indicated that the atomic-level morphology of HA significantly affected the interaction strength between proteins and HA substrates. The interactions of BMP-7 and its derived peptide with nano-concave and nano-pillar HA surfaces were stronger than those with flat or nano-groove HA surfaces. The results also revealed that if the groove size of nano-structured HA surfaces matched that of residues in the protein or peptide, these residues were likely to spread into the grooves of the nano-groove, nano-concave, and nano-pillar HA, further strengthening the interactions. These results are helpful in better understanding the adsorption behaviors of proteins onto nano-structured HA surfaces, and provide theoretical guidance for designing novel bioceramic materials for bone regeneration and tissue engineering.

Magnetic hydroxyapatite: a promising multifunctional platform for nanomedicine application.

In this review, specific attention is paid to the development of nanostructured magnetic hydroxyapatite (MHAp) and its potential application in controlled drug/gene delivery, tissue engineering, magnetic hyperthermia treatment, and the development of contrast agents for magnetic resonance imaging. Both magnetite and hydroxyapatite materials have excellent prospects in nanomedicine with multifunctional therapeutic approaches. To date, many research articles have focused on biomedical applications of nanomaterials because of which it is very difficult to focus on any particular type of nanomaterial. This study is possibly the first effort to emphasize on the comprehensive assessment of MHAp nanostructures for biomedical applications supported with very recent experimental studies. From basic concepts to the real-life applications, the relevant characteristics of magnetic biomaterials are patented which are briefly discussed. The potential therapeutic and diagnostic ability of MHAp-nanostructured materials make them an ideal platform for future nanomedicine. We hope that this advanced review will provide a better understanding of MHAp and its important features to utilize it as a promising material for multifunctional biomedical applications.

One-dimensional hydroxyapatite materials: preparation and applications

As one of the biominerals, hydroxyapatite (HAP) plays important roles in biology, and inspires researchers to investigate HAP-based materials for the applications in various biomedical fields. Among them, one-dimensional (1-D) micro-/nanostructured HAP materials have attracted great interest in the last decades. This review summarizes the preparation and applications of 1-D HAP materials, and discusses different aspects of 1-D HAP materials. Various synthetic methods have been developed to prepare 1-D HAP materials with different morphologies, sizes, surface properties and crystallinities. In addition, elements-substituted 1-D HAP materials and composites have also been prepared. Surfactants and additives are usually adopted to control the nucleation and growth of 1-D HAP materials, but the related mechanisms are not very clear yet. The applications of 1-D HAP materials have been widely investigated, and the biomedical applications show great prospect but still need further improvements. A new kind of highly flexible fire-resistant inorganic paper made of ultralong HAP nanowires has been developed and is a promising alternative of the traditional cellulose paper for valuable archives and important documents. Regardless of the advances, further studies should be made for preparing 1-D HAP materials with controlled structures, sizes and morphologies and for boosting their various applications.

Enhanced biological properties of biomimetic apatite fabricated polycaprolactone/chitosan nanofibrous bio-composite for tendon and ligament regeneration

The development of tailored nanofibrous scaffolds for tendon and ligament tissue engineering has been a goal of clinical research for current researchers. Here, we establish a formation of novel nanofibrous matrix with significant mechanical and biological properties by electro-spinning process. The fine fibrous morphology of the nanostructured hydroxyapatite (HAp) dispersed in the polycaprolactone/chitosan (HAp-PCL/CS) nanofibrous matrix was exhibited by microscopic (SEM and TEM) techniques. The favorable mechanical properties (load and modulus) were achieved. The load and modulus of the HAp-PCL/CS composite fibers was 250.1N and 215.5MPa, which is very similar to that of standard value of the human tendon and ligament tissues. The cellular responses and biocompatibility of HAp-PCL/CS nanofibrous scaffolds were investigated with human osteoblast (HOS) cells for tendon regeneration and examined the primary osteoblast mechanism by in vitro method. The morphological (FE-SEM and fluorescence) microscopic images clearly exhibited that HOS cells are well attached and flatted on the nanofibrous composites. The HAp dispersed PCL/CS nanofibrous scaffolds promoted higher adhesion and proliferation of HOS cells comparable to the nanofibrous scaffolds without HAp nanoparticles. The physic-chemical and biological properties of the synthesized nanofibrous scaffold were very close to that of normal ligament and tendon in human body. Over all, these studied results confirmed that the prepared nanofibrous scaffolds will be effective biomaterial of tendon ligament regeneration applications.

One-Dimensional Hydroxyapatite Nanostructures with Tunable Length for Efficient Stem Cell Differentiation Regulation.

It is well-accepted that most osteogenic differentiation processes do need growth factors assistance to improve efficiency. As a material cue, hydroxyapatite (HAp) can promote osteogenic differentiation of stem cells only in a way. Up to now, rare work related to the relationship between HAp nanostructures and stem cells in osteogenic differentiation process without the assistance of growth factors has been reported. In this study, one-dimensional (1D) HAp nanostructures with tunable length were synthesized by an oleic acid assisted solvothermal method by adjusting the alcohol/water ratio (η). The morphology of 1D HAp nanostructures can be changed from long nanowires into nanorods with the η value change. Different substrates constructed by 1D HAp nanostructures were prepared to investigate the effect of morphology of nanostructured HAp on stem cell fate without any growth factors or differentiation induce media. Human adipose-derived stem cells (hADSCs), a kind of promising stem cell for autologous stem cell tissue engineering, were used as the stem cell model. The experiments prove that HAp morphology can determine the performance of hADSCs cultured on different substrates. Substrate constructed by HAp nanorods (100 nm) is of little benefit to osteogenic differentiations. Substrate constructed on HAp long nanowires (50 μm) causes growth and spread inhibition of hADSCs, which even causes most cells death after 7 days of culture. However, substrate constructed by HAp short nanowires (5 μm) can destine the hADSCs differentiation to osteoblasts efficiently in normal medium (after 3 weeks) without any growth factors. It is surprise that hADSCs have changed to polyhedral morphology and exhibited the tendency to osteogenic differentiation after only 24 h culture. Hydroxyapatite nanostructures mediated stem cell osteogenic differentiation excluding growth factors provides a powerful cue to design biomaterials with special nanostructures, and helps to elucidate the interaction of stem cell and biomaterials nanostructures. The results from this study are promising for application in bone tissue engineering.

In Vitro and in Vivo Study of Poly(Lactic⁻co⁻Glycolic) (PLGA) Membranes Treated with Oxygen Plasma and Coated with Nanostructured Hydroxyapatite Ultrathin Films for Guided Bone Regeneration Processes.

The novelty of this study is the addition of an ultrathin layer of nanostructured hydroxyapatite (HA) on oxygen plasma modified poly(lactic–co–glycolic) (PLGA) membranes (PO2) in order to evaluate the efficiency of this novel material in bone regeneration. Methods: Two groups of regenerative membranes were prepared: PLGA (control) and PLGA/PO2/HA (experimental). These membranes were subjected to cell cultures and then used to cover bone defects prepared on the skulls of eight experimental rabbits. Results: Cell morphology and adhesion of the osteoblasts to the membranes showed that the osteoblasts bound to PLGA were smaller and with a lower number of adhered cells than the osteoblasts bound to the PLGA/PO2/HA membrane (p < 0.05). The PLGA/PO2/HA membrane had a higher percentage of viable cells bound than the control membrane (p < 0.05). Both micro-CT and histological evaluation confirmed that PLGA/PO2/HA membranes enhance bone regeneration. A statistically significant difference in the percentage of osteoid area in relation to the total area between both groups was found. Conclusions: The incorporation of nanometric layers of nanostructured HA into PLGA membranes modified with PO2 might be considered for the regeneration of bone defects. PLGA/PO2/HA membranes promote higher osteosynthetic activity, new bone formation, and mineralisation than the PLGA control group.

Nanostructured hydroxyapatite used as an augmenting material to expand the orbit

PurposeTo test the nanostructured hydroxyapatite as an augmenting material to expand the orbit after initial placement of a porous implant.MethodsNanostructured hydroxyapatite powder mixed with blood was surgically introduced in the scleral sac of 6 eviscated rabbits (Oryctolagus cuniculus europaeus) after previous placing of a porous hydroxyapatite integrated implant (proved by CT scan). CT scans were done at 1, 2 and 3 months postsurgical to demonstrate the integration of the injected material in the porous implant. The scleral sac wes removed after 3 months and histopathologic examination plus CD31 + (as a marker of neovascularization and osteosinthesis) were performed.ResultsCTscans performed at 1, 2 and 3 months postoperatively and the rapid development of CD31 + osteoclasts and vascular tissue pleade for a good integration of the new material in the previous porous hydroxyapatite implant.ConclusionsThis method can be used for enhancing the volume of a small scleral sac with a previous hidroxyapatite implant. Further studies should be performed.

Adhesion of bone marrow mesenchymal stem cells on porous titanium surfaces with strontium-doped hydroxyapatite coating

ObjectiveTo determine the adhesion behavior of bone marrow mesenchymal stem cells (MSCs) on a titanium surface with a nanostructured strontium-doped hydroxyapatite (Sr-HA) coating.MethodsSr-HA coatings were applied on roughened titanium surfaces using an electrochemical deposition method. Primary cultured rat MSCs were seeded onto Sr-HA-, HA-coated titanium, and roughened titanium surfaces, and they were then cultured for 1, 6, and 24 h. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the metabolic condition of the cells. Scanning electron microscopy (SEM) was used to observe the cell morphology. The cytoskeletal structure was analyzed using fluorescence actin staining to characterize cell adherence. Quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) was used to analyze the gene expression levels of FAK (focal adhesion kinase), vinculin, integrin β1, and integrin β3 after culturing for 24, 48, and 72 h.ResultsMSCs cultured on the Sr-HA surface showed better cell proliferation and viability. Improvement of cell adhesion and structural rearrangement of the cytoskeleton were observed on the Sr-HA surface. The gene expression of FAK, vinculin, integrin β1, and integrin β3 was also elevated on the Sr-HA surface.ConclusionsCell viability, adhesion, cell morphology, and the cytoskeletal structure were all upregulated considerably by the titanium surface modified with a Sr-HA coating.

Biostability Assessment of Silver Containing Hydroxyapatite Nanostructures

Biostability Assessment of Silver Containing Hydroxyapatite Nanostructures

A bioprintable form of chitosan hydrogel for bone tissue engineering

Bioprinting can be defined as 3D patterning of living cells and other biologics by filling and assembling them using a computer-aided layer-by-layer deposition approach to fabricate living tissue and organ analogs for tissue engineering. The presence of cells within the ink to use a ‘bio-ink’ presents the potential to print 3D structures that can be implanted or printed into damaged/diseased bone tissue to promote highly controlled cell-based regeneration and remineralization of bone. In this study, it was shown for the first time that chitosan solution and its composite with nanostructured bone-like hydroxyapatite (HA) can be mixed with cells and printed successfully. MC3T3-E1 pre-osteoblast cell laden chitosan and chitosan-HA hydrogels, which were printed with the use of an extruder-based bioprinter, were characterized by comparing these hydrogels to alginate and alginate-HA hydrogels. Rheological analysis showed that all groups had viscoelastic properties. It was also shown that under simulated physiological conditions, chitosan and chitosan-HA hydrogels were stable. Also, the viscosity values of the bio-solutions were in an applicable range to be used in 3D bio-printers. Cell viability and proliferation analyses documented that after printing with bio-solutions, cells continued to be viable in all groups. It was observed that cells printed within chitosan-HA composite hydrogel had peak expression levels for early and late stages osteogenic markers. It was concluded that cells within chitosan and chitosan-HA hydrogels had mineralized and differentiated osteogenically after 21 days of culture. It was also discovered that chitosan is superior to alginate, which is the most widely used solution preferred in bioprinting systems, in terms of cell proliferation and differentiation. Thus, applicability and printability of chitosan as a bio-printing solution were clearly demonstrated. Furthermore, it was proven that the presence of bone-like nanostructured HA in alginate and chitosan hydrogels improved cell viability, proliferation and osteogenic differentiation.

Investigation on biophysical properties of Hydroxyapatite/Graphene oxide (HAp/GO) based binary nanocomposite for biomedical applications

A simple hydrothermal procedure was implemented to prepare hydroxyapatite (HAp) nanorods grown on graphene oxides (GO) sheet. The crystalline structure, chemical composition and morphology of the as-prepared nanocomposites were characterized by using X-ray diffraction, Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Nanorods like HAp nanostructure with the diameter and length in the range of ∼32 and 60–85 nm were uniformly grown on GO sheets. A possible formation mechanism of HAp nanorods grown on GO is proposed. Further, the bio-physical properties of HAp/GO nanocomposites were studied by using Bovine Serum Albumin (BSA) as a model protein. The particle surface effects on the BSA structure, the HAp/GO -protein composites were studied by circular dichroism (CD) between 200 and 260 nm. Result conforms, the primary structure of the 10 μM BSA exhibits a characteristic alpha-helix spectrum between wavelength 200–240, after 12 h incubation of the BSA with HAp/GO, no significant change in the alpha helix pattern of the BSA. Moreover, human skin cancer cells (A431) was used to determine the cytotoxicity of HAp/GO nanocomposites at various concentrations of 50–500 μg/mL for 24 h and the cytotoxicity was observed using MTT assays. The as-prepared HAp/GO nanocomposites showed no cytotoxicity effects on A431 cancer cell lines. Significance of this study shows that the as-prepared HAp/GO nanocomposites provide excellent biocompatibility which was used orthopedic, drug delivery and dentistry applications.