Bing-Qiang Lu

Hydroxyapatite Hierarchically Nanostructured Porous Hollow Microspheres: Rapid, Sustainable Microwave-Hydrothermal Synthesis by Using Creatine Phosphate as an Organic Phosphorus Source and Application in Drug Delivery and Protein Adsorption.

Hierarchically nanostructured porous hollow microspheres of hydroxyapatite (HAP) are a promising biomaterial, owing to their excellent biocompatibility and porous hollow structure. Traditionally, synthetic hydroxyapatite is prepared by using an inorganic phosphorus source. Herein, we report a new strategy for the rapid, sustainable synthesis of HAP hierarchically nanostructured porous hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through a microwave-assisted hydrothermal method. The as-obtained products are characterized by powder X-ray diffraction (XRD), Fourier-transform IR (FTIR) spectroscopy, SEM, TEM, Brunauer-Emmett-Teller (BET) nitrogen sorptometry, dynamic light scattering (DLS), and thermogravimetric analysis (TGA). SEM and TEM micrographs show that HAP hierarchically nanostructured porous hollow microspheres consist of HAP nanosheets or nanorods as the building blocks and DLS measurements show that the diameters of HAP hollow microspheres are within the range 0.8-1.5 μm. The specific surface area and average pore size of the HAP porous hollow microspheres are 87.3 m(2) g(-1) and 20.6 nm, respectively. The important role of creatine phosphate disodium salt and the influence of the experimental conditions on the products were systematically investigated. This method is facile, rapid, surfactant-free and environmentally friendly. The as-prepared HAP porous hollow microspheres show a relatively high drug-loading capacity and protein-adsorption ability, as well as sustained drug and protein release, by using ibuprofen as a model drug and hemoglobin (Hb) as a model protein, respectively. These experiments indicate that the as-prepared HAP porous hollow microspheres are promising for applications in biomedical fields, such as drug delivery and protein adsorption.

Hydroxyapatite nanosheet-assembled porous hollow microspheres: DNA-templated hydrothermal synthesis, drug delivery and protein adsorption

Porous hollow microspheres of hydroxyapatite (HAP) are an ideal biomaterial due to their excellent biocompatibility and hollow structure. Herein, we report a novel DNA-templated hydrothermal strategy for the synthesis of HAP nanosheet-assembled hollow microspheres with a nanoporous structure. The as-prepared HAP porous hollow microspheres consist of HAP nanosheets as the building blocks with an average thickness of about 20 nm, and the diameters of the HAP porous hollow microspheres are in the range 2.5–4.5 μm, with an average pore size of about 21.8 nm. The as-prepared HAP porous hollow microspheres are explored for potential applications in drug delivery, and protein adsorption and release. The as-prepared HAP porous hollow microspheres show a relatively high drug loading capacity and protein adsorption ability, and sustained drug and protein release, using ibuprofen as a model drug and hemoglobin (Hb) as a model protein. The experiments indicate that the as-prepared HAP porous hollow microspheres are promising for applications in biomedical fields such as drug delivery and protein adsorption.

Highly Flexible and Nonflammable Inorganic Hydroxyapatite Paper

A highly flexible and nonflammable inorganic hydroxyapatite (HAP) paper made from HAP ultralong nanowires is reported. The paper can be used for printing and writing and is promising for the permanent and safe storage of information, such as archives and important documents. The HAP paper is also an excellent and recyclable adsorbent for organic pollutants.

Nanosheet-assembled hierarchical nanostructures of hydroxyapatite: surfactant-free microwave-hydrothermal rapid synthesis, protein/DNA adsorption and pH-controlled release

In this paper, a surfactant-free rapid microwave-assisted hydrothermal synthesis of hydroxyapatite nanosheet-assembled flower-like hierarchical nanostructures (NFHNs) is reported. The effects of the experimental conditions on the morphology and crystal phase of the product are investigated. A possible formation mechanism of hydroxyapatite NFHNs is proposed. The morphology of the product can vary from flower-like to polyhedra by adjusting the microwave heating temperature. The protein and DNA adsorption properties of the as-prepared hydroxyapatite NFHNs are studied. The loading capacities of the as-prepared hydroxyapatite NFHNs for bovine serum albumin (BSA), hemoglobin (Hb) and fish sperm DNA are determined to be 165, 164 and 112 mg g−1, respectively. The protein release process is conducted at different pH values (pH 7.2, 5.5 and 4.8) in phosphate buffer saline (PBS), and the pH-controlled protein release behavior has been found. Thus, the as-prepared hydroxyapatite NFHNs are promising for protein drug delivery applications.

Hydroxyapatite nanosheet-assembled microspheres: hemoglobin-templated synthesis and adsorption for heavy metal ions.

Hydroxyapatite (HAP) nanostructures have wide potential applications in many fields such as drug delivery, tissue engineering, bone repair, gas sensing, catalysis and water treatment. Inspired with the fact that HAP has a high affinity with proteins, we have designed and developed a new synthetic strategy for three-dimensional (3-D) HAP nanosheet-assembled microspheres (HAP-NMSs) by employing hemoglobin as a soft template. The as-prepared products are characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (SEM). The experimental results show that 3-D HAP microspheres are constructed by the self-assembly of HAP nanosheets as the building blocks. The influences of hemoglobin concentration, hydrothermal temperature and time on the morphology and crystal phase of the product are investigated. Based on the systematic investigation, a possible formation mechanism of HAP-NMSs is proposed. The as-prepared HAP-NMSs are explored for the potential application in water treatment. The experimental results indicate that the HAP-NMSs have a high adsorption capacity for heavy metal ions and selective adsorption activity for Pb(2+) ions in acidic solution, thus are promising for the application in wastewater treatment.

Chitosan-coated mesoporous microspheres of calcium silicate hydrate: Environmentally friendly synthesis and application as a highly efficient adsorbent for heavy metal ions

Chitosan-coated calcium silicate hydrate (CSH/chitosan) mesoporous microspheres formed by self-assembly of nanosheets have been synthesized in aqueous solution under ambient conditions without using any toxic surfactant or organic solvent. The method reported herein has advantages of simplicity, low cost and being environmentally friendly. The BET specific surface area of CSH/chitosan mesoporous microspheres is measured to be as high as ~356 m(2) g(-1), which is considerably high among calcium silicate materials. The as-prepared CSH/chitosan mesoporous microspheres are promising adsorbent and exhibit a quick and highly efficient adsorption behavior toward heavy metal ions of Ni(2+), Zn(2+), Cr(3+), Pb(2+) Cu(2+) and Cd(2+) in aqueous solution. The adsorption kinetics can be well fitted by the pseudo second-order model. The maximum adsorption amounts of Ni(2+), Zn(2+), Pb(2+), Cu(2+) and Cd(2+) on CSH/chitosan mesoporous microspheres are extremely high, which are 406.6, 400, 796, 425 and 578 mg/g, respectively. The CSH/chitosan adsorbent exhibits the highest affinity for Pb(2+) ions among five heavy metal ions. The adsorption capacities of the CSH/chitosan adsorbent toward heavy metal ions are relatively high compared with those reported in the literature.

Porous hollow microspheres of amorphous calcium phosphate: soybean lecithin templated microwave-assisted hydrothermal synthesis and application in drug delivery

Calcium phosphate biomaterials are very promising for various biomedical applications owing to their excellent biocompatibility and biodegradability. Calcium phosphate nanostructured materials with a porous and hollow structure are excellent drug carriers due to their advantages such as high biocompatibility, large specific surface area, nanosized channels for drug loading and release, high drug loading capacity and pH-responsive drug release behavior. In this work, porous hollow microspheres of amorphous calcium phosphate have been successfully prepared by the microwave-assisted hydrothermal method using adenosine triphosphate disodium salt, CaCl2 and soybean lecithin in aqueous solution. This preparation method is facile, rapid, energy-saving and environment friendly. The effects of microwave hydrothermal temperature and concentrations of the reactants on the morphology and structure of the product were investigated. The as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The as-prepared porous hollow microspheres of amorphous calcium phosphate are efficient for drug loading and release, and the drug delivery system shows a pH-responsive drug release behavior and high ability to damage tumor cells. Thus, the as-prepared porous hollow microspheres of amorphous calcium phosphate are promising for the applications in various biomedical fields.

Hydrothermal synthesis of hydroxyapatite nanorods and nanowires using riboflavin-5′-phosphate monosodium salt as a new phosphorus source and their application in protein adsorption

Hydroxyapatite (HA), as the main inorganic constituent in vertebrate hard tissues, is an important biomaterial for the application in drug delivery and protein adsorption. Herein, we report a simple and green hydrothermal synthesis of HA nanorods and nanowires by using the biocompatible biomolecule riboflavin-5′-phosphate monosodium salt (RP) as a new phosphorus source. In this method, the RP molecules hydrolyze to form inorganic phosphate ions under hydrothermal conditions, and these phosphate ions react with calcium ions to form HA nanorods or nanowires after nucleation and crystal growth. The effects of experimental conditions including hydrothermal temperature, heating time and pH value of the initial solution on the hydrolysis process of RP molecules are investigated. A possible formation mechanism of HA nanorods and nanowires is proposed. The as-prepared HA nanorods and nanowires are explored for the potential application in protein adsorption. The hemoglobin (Hb) loading capacities of HA nanowires and HA nanorods increase with increasing initial Hb concentration. The Hb loading capacities of HA nanowires and HA nanorods are determined to be as high as 289 mg g−1 and 298 mg g−1, respectively, at an initial Hb concentration of 2000 mg mL−1. The pH-dependent Hb release property of Hb-loaded HA nanowires and HA nanorods has been found. The experimental results indicate that the products are promising for applications in protein adsorption.

Solvothermal synthesis of oriented hydroxyapatite nanorod/nanosheet arrays using creatine phosphate as phosphorus source

Synthesis of hydroxyapatite (HAp) oriented arrays is difficult but significant in biomineralization research for biomaterials. Herein, a novel strategy for the synthesis of HAp nanorod/nanosheet oriented arrays has been developed in the presence of biomolecules of creatine phosphate (CP) using solvothermal treatment in mixed solvents of N,N-dimethylformamide (DMF) and water. In this reaction system, CP biomolecules act as an organic phosphorus source and a soft template for the formation of HAp oriented arrays. This method does not need any hard template or surfactant, avoiding the procedures and cost for their removal from the product. The products are characterized with X-ray powder diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The formation mechanism of HAp nanorod/nanosheet oriented arrays is discussed.

Magnetic nanocomposite of hydroxyapatite ultrathin nanosheets/Fe3O4 nanoparticles: microwave-assisted rapid synthesis and application in pH-responsive drug release

Synthetic hydroxyapatite (HAP) nanostructured materials have been considered as promising biomaterials due to their excellent biocompatibility. In this study, a magnetic nanocomposite consisting of HAP ultrathin nanosheets (UNs) and Fe3O4 magnetic nanoparticles (MNs) has been prepared using a rapid microwave-assisted route. The Fe3O4 magnetic nanoparticles are hybridized with HAP ultrathin nanosheets, which self-assemble to form a hierarchically nanostructured magnetic nanocomposite (HAPUN/MNs). The as-prepared HAPUN/MNs nanocomposite is characterized and investigated as a drug nanocarrier using hemoglobin (Hb) and docetaxel (Dtxl) as model drugs. The adsorption amount of Hb on the HAPUN/MNs nanocomposite increases with the increasing initial Hb concentration. The release of Hb from the HAPUN/MNs nanocomposite is essentially governed by a diffusion process. The HAPUN/MNs nanocomposite has a good sustained release profile for Dtxl, and shows good pH-responsive drug release properties, which can be explained by the gradual dissolution of HAP in a low pH value environment. The HAPUN/MNs nanocomposite has a high biocompatibility and also a high in vitro anticancer effect after loading Dtxl.