Calcium Phosphate Nanospheres Research Articles

3D-Printed Scaffolds of Porous Amorphous Calcium Phosphate Nanospheres Loaded with Quercetin for Promoting Bone Repair via Synergistic Osteogenesis and Immunoregulation

3D-Printed Scaffolds of Porous Amorphous Calcium Phosphate Nanospheres Loaded with Quercetin for Promoting Bone Repair via Synergistic Osteogenesis and Immunoregulation

Hybrid functional membranes through layer-by-layer assembly of Ti3C2Tx MXene and gelatin-stabilized calcium phosphate nanospheres

MXene-based membranes exhibit promising properties for various applications; however, pure MXene membranes lack sufficient environmental stability and mechanical strength. This work demonstrates that incorporating gelatin-stabilized amorphous calcium phosphate (Gel-ACP) nanospheres into MXene membranes via layer-by-layer assembly significantly enhances flexibility and mechanical strength while retaining electrical conductivity. A pressure-assisted stacking technique was introduced to efficiently fabricate membranes with tunable thickness not achievable through single filtration steps. The Gel-ACP nanospheres, synthesized by co-precipitation of calcium phosphate within gelatin solution, provided a ductile and cytocompatible reinforcement that augmented the properties of the MXene matrix. Direct mixing of the components led to particle aggregation and non-uniform dispersion. In contrast, controlled layer-by-layer nanostructuring maintained membrane conductivity around 102 Scm−1 while dramatically improving mechanical integrity. The optimized hybrid membranes exhibited specific electromagnetic shielding effectiveness of ∼21,000 dBcm2g−1 and withstood over 90 kPa vacuum pressure without rupture, six times higher than pure MXene membranes. Cytocompatibility was confirmed by the proliferation of human mesenchymal stem cells on the membranes. Moreover, the layered membrane exhibited excellent adhesion to bone-mimicking structures, indicating potential utility for bone tissue engineering. Overall, this work provides new design principles for engineering hybrid membranes through controlled multicomponent assembly to overcome intrinsic limitations and impart multifunctionality.

Precise morphology control of phosphate-based nanospheres via magnesium and application in drug delivery

The present work investigates a template-free and rapid synthesis of phosphate-based porous nanospheres via magnesium. The study reveals the magnesium plays a guide role in the formation of amorphous porous magnesium substituted nanospheres, including calcium phosphate (CaP), strontium phosphate (SrP) and barium phosphate (BaP). Cell viabilities of three kinds of particles were evaluated and CaP nanospheres indicated best biocompatibility. Thus, amorphous magnesium substituted CaP nanospheres were chosen as doxorubicin (DOX) carrier for drug delivery in cancer treatment and pH-responsive magnesium substitution can switch on under tumour acidic microenvironment and facilitate controlled sustained DOX release. The CaP nanospheres gave a sustainable release within 150 minutes. The results showed free DOX has better efficiency at killing cancer cells than CaP/DOX at 4 h. However, CaP/DOX systems effectively suppressed the cell proliferation comparing with free DOX at 36 h. Collectively, this simple and templet-free method for synthesis of amorphous porous nanospheres could serve as a promising chemo-therapeutics delivery system and effectively inhibition of cancer cell growth.

Dialysis Preparation of Smart Redox and Acidity Dual Responsive Tea Polyphenol Functionalized Calcium Phosphate Nanospheres as Anticancer Drug Carriers.

Large-scale preparation of biocompatible drug delivery systems with targeted recognition and controlled release properties has always been attractive. However, this strategy has been constrained by a lot of design challenges, such as complicated steps and premature drug release. Herein, in this paper, we address these problems by a facile in situ mineralization method, which synthesizes biodegradable tea polyphenol coated monodisperse calcium phosphate nanospheres using for targeted and controlled delivery of doxorubicin. Dialysis diffusion method was used to control ion release to form mineralized nanospheres. The polyphenol coatings and calcium phosphate used in this work could be biodegraded by intracellular glutathione and acidic microenvironment, respectively, resulting the release of encapsulated drug. According to confocal fluorescence microscopy, and cytotoxicity experiments, the prepared tea polyphenol functionalized, doxorubicin loaded calcium phosphate nanospheres were confirmed to have highly efficient internalization and obvious cell killing effect on target tumor cells, but not normal cells. Our results suggest that these tea polyphenols functionalized calcium phosphate nanospheres are promising vehicles for controlled release of an anticancer drug in cancer therapy.

A novel rapid synthesis, characterization and applications of calcium phosphate nanospheres from Baltic seawater

Due to the considerable high bio-compatibility, calcium phosphate nanoparticles are widely used in biomedical applications. This study proposes a novel strategy for low-cost manufacturing calcium phosphate nanoporous spheres. The controlled reaction only took less than five minutes, when using Baltic seawater with the dissolved calcium concentration of 2.2 mM as the calcium resources. Porous nanospheres were obtained, with spheres ranging from 50 to 130 nm. The obtained nanospheres possess high drug-loading capacity and exhibit sustained release and pH-dependent properties. In addition, this method provides a general efficient strategy to synthesize other low-cost inorganic nanospheres from seawater.

Biologically inspired, catechol-coordinated, hierarchical organization of raspberry-like calcium phosphate nanospheres with high specific surface area.

The elaborate design of calcium phosphates (CaP) with a hierarchical structure for biomedical applications is severely restricted due to their instinctive pertinacious irregular agglomeration. Thus, the development of mesoporous CaP with large internal pores is far from satisfactory. In this study, catechol is selected as a modifier to intervene in the precipitation of CaP. Compared to pure CaP with smooth irregular aggregates with an average size of 110 nm, the catechol-intervened CaP (CaP/Cat) samples are raspberry-like nano-spherical assemblies of ca. 25 nm nanoparticles. The obtained spheres possess a mesoporous structure, large interior pores and high specific surface area, which endow them with a high protein adsorption capacity and high DNA delivery efficacy. Catechol is subjected to oxidative polymerization while CaP precipitation occurs. This simultaneous reaction is supposed to play a crucial role in directing the assembling of the CaP/Cat nanospheres. The flexible catechol moiety is shown to be a novel and promising modifier for manufacturing CaP with tunable structures and properties for various applications.

IgY-loaded calcium phosphate nanospheres: Preparation, sustained release and antibacterial activity

IgY-loaded calcium phosphate nanospheres: Preparation, sustained release and antibacterial activity

Nanoscale analysis of calcium phosphate films obtained by RF magnetron sputtering during the initial stages of deposition

In the present work, we investigated the nanostructure of calcium phosphate films formed during the initial stages of deposition (between 30 and 240s; deposition rate of 3.7nm/min) by radio-frequency magnetron sputtering. The sputtering deposition parameters and the plasma energy were previously adjusted to produce nearly stoichiometric nanocrystalline hydroxyapatite films after 180min. Grazing-incidence X-ray diffraction and X-ray photoelectron spectroscopy analyses revealed that the films formed in the initial stages were composed of an amorphous calcium phosphate phase with a Ca/P ratio Ca/P=1.60±0.12, which is close to that of hydroxyapatite. Using high-resolution transmission electron microscopy, we demonstrated that the films were not a unique amorphous phase. An additional phase composed of dense calcium phosphate nanospheres was found in all periods and investigated. The nanospheres grew in size as the deposition time increased, and small nanospheres were always observed. This observation suggests the continuous formation of nanospheres at the surface of the film. Nanocrystalline regions were revealed by electron diffraction and high-resolution electron microscopy after a deposition of 60s with a corresponding film thickness of 3.7nm. Electron energy-loss spectroscopy analysis comparing individual nanospheres to the amorphous calcium phosphate layer showed differences in the oxygen K edge, suggesting a difference in the chemical bonding of the oxygen species. Nanospheres were observed in association with isolated crystals, suggesting that the nanospheres may participate in the crystallization of hydroxyapatite according to a heterogeneous nucleation process.

An amorphous calcium phosphate nanocomposite for storing and sustained release of IgY protein with antibacterial activity

Amorphous calcium phosphate nanospheres with/without La doping are prepared and used for IgY storing, sustained release and antibacterial study.

Biomimetic synthesis of hollow calcium phosphate nanospheres on core–shell structured electrospun calcium lactate/nylon-6 nanofibers

The aim of this study was to investigate into calcium phosphate (CaP) nucleation and growth on the electrospun nylon-6 nanofibers having its own and added functionalities of lactic acid (LA) and calcium lactate (CL) obtained by novel coating technique. LA was simply incorporated into the nylon-6 fibers by means of simple blending prior to electrospinning where as CL was deposited on the surface of as-formed core–shell structured fibers via simple acid–base neutralization. The bone formation ability of different functional groups on the fiber was evaluated by incubating in simulated body fluid. This study demonstrated a functionalities depended nucleation and growth mechanism of hollow CaP nanosphere on the surface of polymeric nanofibers.

Novel microwave synthesis of amorphous calcium phosphate nanospheres

Amorphous calcium phosphate (ACP) is an important precursor phase in tissue mineralization. It shows high solubility and excellent remineralization ability. Commercially viable techniques for producing ACP are high-cost/low-efficiency process. This article describes a novel microwave (MW)-assisted ACP synthesis route as an alternative to current ACP synthesis methods. An important feature of the process is the use of supersaturated biomimetic fluids (SBFs), which are based on Kokubo-like simulated body fluids. However, our present compositions are substantially different in that they no longer simulate the body fluid compositions. The effects of solution composition and processing parameters were studied. The mechanism of ACP synthesis under MW irradiation process is also discussed. The as-synthesized ACP nanospheres were characterized and showed good reactivity and biocompatibility. These as-synthesized nanoparticles can be potential candidates for biomedical applications and remineralization mechanism study.

A block copolymer micelle template for synthesis of hollow calcium phosphate nanospheres with excellent biocompatibility

We report synthesis of hollow calcium phosphate (CaP) nanospheres with high surface area by using block copolymer micelles as templates. The obtained CaP nanospheres exhibit very high biocompatibility, showing great promise for intracellular bio-applications in future.

Ibuprofen loaded porous calcium phosphate nanospheres for skeletal drug delivery system

Porous calcium phosphate nanospheres were successfully fabricated by a simple sonochemical method, and used as a drug carrier of ibuprofen. Morphology, structure, ibuprofen storage capacity, and release rate of the calcium phosphate nanospheres were characterized using FE-SEM, TEM, Nitrogen adsorption, XRD, FTIR, and UV–vis adsorption spectroscopies. Results showed the obtained calcium phosphate nanospheres held a porous structure with an average diameter of 48.9 ± 17.42 nm. Moreover, the porous nanospheres possessed an adjustable load amount and release rate for ibuprofen by changing drug concentrations during the drug loading process. In addition, the effects of size and dispersancy of porous spheres on drug release rate were discussed, which was found that larger or agglomerate porous spheres could delay drug release process. This study indicated that porous calcium phosphate nanospheres were a perfect drug carrier for ibuprofen, which has potential application for the therapy of skeletal disease.

Mapping amorphous calcium phosphate transformation into crystalline mineral from the cell to the bone in zebrafish fin rays

The continuously forming fin bony rays of zebrafish represent a simple bone model system in which mineralization is temporally and spatially resolved. The mineralized collagen fibrils of the fin bones are identical in structure to those found in all known bone materials. We study the continuous mineralization process within the tissue by using synchrotron microbeam x-ray diffraction and small-angle scattering, combined with cryo-scanning electron microscopy. The former provides information on the mineral phase and the mineral particles size and shape, whereas the latter allows high-resolution imaging of native hydrated tissues. The integration of the two techniques demonstrates that new mineral is delivered and deposited as packages of amorphous calcium phosphate nanospheres, which transform into platelets of crystalline apatite within the collagen matrix.

Controlled mineralization by extracellular matrix: monodisperse, colloidally stable calcium phosphate-hyaluronan hybrid nanospheres

Uniform, monodisperse calcium phosphate nanospheres (40 nm) were prepared using a simple co-precipitation method via the segregation crystallization imposed by hyaluronan molecules. The nanospheres exhibit excellent colloidal/storage stability in water due to the incorporated extracellular substance.

Ultrasonic Controlled Morphology Transformation of Hollow Calcium Phosphate Nanospheres: A Smart and Biocompatible Drug Release System

Hollow-structured calcium phosphate nanospheres can be transferred into pin-shaped crystallites under the ultrasonic treatments, the release of encapsulated compounds can be on/off triggered, and its kinetics is precisely regulated by the power density, duty cycle, and application time of ultrasound.