Ying-Ying Jiang

Sonochemical synthesis of hydroxyapatite nanoflowers using creatine phosphate disodium salt as an organic phosphorus source and their application in protein adsorption

In this paper, the one-step rapid synthesis of hydroxyapatite nanoflowers (HAFs) using creatine phosphate disodium salt as an organic phosphorus source by the sonochemical method is reported. The HAFs with diameters of about 300 nm are formed by self-assembly of hydroxyapatite nanosheets with thicknesses of less than 10 nm. The as-prepared samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) nitrogen sorptometry, X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and inductively coupled plasma (ICP) optical emission spectroscopy. The MTT tests show that the as-prepared HAFs exhibit essentially inappreciable toxicity to MC-3T3 osteoblast cells, indicating that the HAFs have an excellent cytocompatibility. Moreover, the as-prepared HAFs show a relatively high protein adsorption ability when using hemoglobin (Hb) as a model protein. Thus, the as-prepared HAFs are promising for applications in various biomedical fields such as protein/drug delivery.

Templated solvothermal synthesis of magnesium silicate hollow nanospheres with ultrahigh specific surface area and their application in high-performance protein adsorption and drug delivery

Magnesium silicate nanostructured biomaterials with good biocompatibility and high adsorption capacity for drugs and proteins are promising for applications in various biomedical fields. However, the applications of magnesium silicate nanostructured biomaterials in anticancer drug delivery and protein adsorption have rarely been reported so far. Herein, we report a facile strategy for the synthesis of magnesium silicate hollow nanospheres (MSHNSs) by a classical Stöber method and a template based solvothermal process. The as-prepared MSHNSs have an ultrahigh specific surface area of 585.6 m2 g-1, ultrahigh hemoglobin (Hb) protein adsorption capacity (1262 mg g-1) and high doxorubicin (DOX) drug loading capacity (559 mg g-1). Moreover, the as-prepared MSHNS/DOX drug delivery system exhibits sustained and pH-responsive drug release performance. Compared with free DOX, the MSHNS/DOX drug delivery system exhibits higher anticancer activity in vitro, and thus it is promising for applications in anticancer treatment.

New strategy for the in situ synthesis of single-crystalline MnWO4/TiO2 photocatalysts for efficient and cyclic photodegradation of organic pollutants

MnWO4 nano photocatalysts with plate shapes and in high yields are in situ synthesized on the surface of a porous TiO2 film by the conventional plasma electrolytic oxidation (PEO) method combined with a subsequent ambient annealing process. Transmission electron microscopy (TEM) analysis shows that the MnWO4 nano photocatalysts are single crystals free of structural defects and scanning electron microscopy (SEM) observation on the cross-section reveals that these MnWO4 nano photocatalysts are in situ grown on the porous TiO2 film surface with strong adhesion. The morphology and dimension size can be selectively tailored through controlling the reaction time, showing the simplicity and versatility of the proposed method. In addition, the photodegradation of methylene blue (MB) solution using the MnWO4/TiO2 photocatalysts demonstrated the superior photocatalytic performance with high efficiency and excellent photostability. A high photodegradation rate of MB solution of over 90% in 60 min has been achieved and a superior cyclic capability is also obtained. The superior photocatalytic performance of MnWO4/TiO2 photocatalysts can be mainly attributed to the good crystallinity, all-surface covering and strong mechanical properties of the MnWO4 nanostructures with TiO2 film. The prevailing advantage of the PEO method in combination with the ambient annealing process will open up more opportunity for the rational synthesis of a wide range of oxide photocatalysts ranging from tungstate to titanate, molybdate and vanadate for promising catalytic applications in diverse fields.

Preparation and enhanced mechanical properties of hybrid hydrogels comprising ultralong hydroxyapatite nanowires and sodium alginate

Hydrogels with 3-dimentional cross-linked structures are widely used in various biomedical fields such as bone repair scaffolds, drug carriers and biosensors. However, the applications of hydrogels are usually restricted because of their poor mechanical properties. Currently, nanocomposites, double network systems, hydrophobic association, macromolecules, and nanoparticles are commonly adopted as cross-linking agents to enhance mechanical properties of hydrogels. In this work, ultralong hydroxyapatite nanowires (HANWs) with lengths of several hundred microns are prepared and used to enhance the mechanical properties of sodium alginate (SA)-based hydrogels. Using divalent calcium ions as the cross-linking agent, the hybrid HANWs/SA hydrogels containing various percentages of HANWs are obtained. The as-prepared HANWs/SA hybrid hydrogels have a porous structure with pore sizes ranging from about 200 to 500μm. The mechanical properties of SA hydrogels can be significantly improved by incorporating HANWs. The maximum compressive modulus (E50%) and tensile Youngs modulus of the hybrid hydrogel (HANWs/SA=2:1) are as high as 0.123MPa and 0.994MPa, which are about 162% and 614% those of the pure SA hydrogel, respectively. Due to the enhanced mechanical properties and high biocompatibility, the as-prepared HANWs/SA hybrid hydrogels have promising applications in various biomedical fields such as bone defect repair.

Binary Strengthening and Toughening of MXene/Cellulose Nanofiber Composite Paper with Nacre-Inspired Structure and Superior Electromagnetic Interference Shielding Properties

With the growing popularity of electrical communication equipment, high-performance electromagnetic interference (EMI) shielding materials are widely used to deal with radiation pollution. However, the large thickness and poor mechanical properties of many EMI shielding materials usually limit their applications. In this study, ultrathin and highly flexible Ti3C2T x (d-Ti3C2T x, MXene)/cellulose nanofiber (CNF) composite paper with a nacre-like lamellar structure is fabricated via a vacuum-filtration-induced self-assembly process. By the interaction between one-dimensional (1D) CNFs and two-dimensional (2D) d-Ti3C2T x MXene, the binary strengthening and toughening of the nacre-like d-Ti3C2T x/CNF composite paper has been successfully achieved, leading to high tensile strength (up to 135.4 MPa) and fracture strain (up to 16.7%), as well as excellent folding endurance (up to 14 260 times). Moreover, the d-Ti3C2T x/CNF composite paper exhibits high electrical conductivity (up to 739.4 S m-1) and excellent specific EMI shielding efficiency (up to 2647 dB cm2 g-1) at an ultrathin thickness (minimum thickness 47 μm). The nacre-inspired strategy in this study offers a promising approach for the design and preparation of the strong integrated and flexible MXene/CNF composite paper, which may be applied in various fields such as flexible wearable devices, weapon equipment, and robot joints.

Ultralong hydroxyapatite microtubes: solvothermal synthesis and application in drug loading and sustained drug release

In this work, monodisperse single-crystalline ultralong hydroxyapatite (HAP) microtubes have been successfully synthesized using a reaction system containing CaCl2, NaOH, (NaPO3)6, oleic acid, water and ethanol by a solvothermal method. The formation mechanism of HAP microtubes and the effects of solvothermal temperature, pH value, Ca/P molar ratio, and volume ratio of solvents on the product have been investigated. Due to the unique tubular structure, the as-prepared ultralong HAP microtubes exhibit high biocompatibility and superior properties in drug loading and sustained drug release. The as-prepared HAP microtubes are promising for applications in various biomedical fields such as drug/gene delivery and bone defect repair.

Design of a novel wound dressing consisting of alginate hydrogel and simvastatin-incorporated mesoporous hydroxyapatite microspheres for cutaneous wound healing

Wound dressings with pro-angiogenic activity are desirable for the rapid healing of full-thickness cutaneous wounds. It is well accepted that simvastatin can stimulate angiogenesis in addition to its lipid-lowering efficacy. However, the construction of a hydrogel-based wound dressing containing simvastatin remains a challenge due to its water-insolubility. In the present study, a novel wound dressing composed of alginate hydrogel (AH) and simvastatin-incorporated mesoporous hydroxyapatite microspheres (S-MHMs) was constructed for the sustained drug release of simvastatin. We first investigated the effect of simvastatin on the angiogenic differentiation of human umbilical vein endothelial cells (HUVECs). The in vitro results revealed that simvastatin significantly promoted the migration and tube formation of HUVECs. Furthermore, the activation of the Akt and Erk signaling pathways was detected in HUVECs upon treatment with simvastatin, and enhanced tube formation was reversed by LY294002 and PD98059, which indicated that both the Akt and Erk signaling pathways were involved in the process of angiogenesis induced by simvastatin. Moreover, simvastatin significantly up-regulated the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF), which play essential roles in angiogenesis. For the in vivo experiments, simvastatin was incorporated into mesoporous hydroxyapatite microspheres (MHMs) synthesized using fructose 1,6-bisphosphate trisodium salt (FBP) as the phosphorous source by the microwave-assisted hydrothermal method. An simvastatin-loaded MHMs (S-MHMs) incorporated alginate hydrogel (S-MHMs/AH) was prepared as a wound dressing to promote the full-thickness cutaneous wound healing. The results demonstrated that S-MHMs/AH significantly enhanced new blood vessel formation and accelerated the reepithelialization of the cutaneous wounds. The present study suggests the potential application of the S-MHMs/AH composite as a novel dressing for wound healing.

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

The synthesis of multifunctional biomaterials with antibacterial activity and remineralization effect on demineralized enamel remains a great challenge in the dental research field. Herein, we use chicken immunoglobulin Y (IgY) and amorphous calcium phosphate (ACP) nanospheres to prepare a nanocomposite with the multifunctional properties of antibacterial activity and remineralized effect. ACP nanospheres and La-ACP nanospheres with an amorphous structure are prepared by a simple coprecipitation method. Then, the as-prepared ACP nanospheres and La-ACP nanospheres which have high protein adsorption capacity are functionalized by adsorbing IgY molecules. After loading IgY, the ACP nanospheres and La-ACP nanospheres exhibit significant antibacterial activity against Sreptococcus mutans (S. mutans). Through the sustained release of IgY molecules and the mineralization of ACP nanospheres in simulated saliva fluid (SSF), the IgY-loaded ACP nanospheres have potential application in simultaneous inhibition of harmful oral bacteria and remineralization of demineralized tooth enamel. Due to the high biocompatibility, the as-prepared IgY-loaded ACP nanospheres and IgY-loaded La-ACP nanospheres are promising for prophylaxis and treatment of dental caries.

Hydroxyapatite nanorod-assembled porous hollow polyhedra as drug/protein carriers

Hydroxyapatite (HAP) with a porous hollow structure is an ideal biomaterial owing to its excellent biocompatibility and unique architecture. In this study, HAP nanorod-assembled porous hollow polyhedra, consisting of nanorod building blocks, have been successfully prepared at room temperature or under hydrothermal circumstances using a self-sacrificing Ca(OH)2 template strategy. The hydrothermal treatment (at 180°C for 1h) can promote the HAP nanorods to be arranged with their axial direction normal to the polyhedron surface. The HAP nanorod-assembled porous hollow polyhedra have been explored for the potential application in drug/protein delivery, using ibuprofen (IBU) as a model drug and hemoglobin (Hb) as a model protein. The experimental results indicate that the HAP nanorod-assembled porous hollow polyhedra have a relatively high drug loading capacity and protein adsorption ability, and sustained drug and protein release. The HAP nanorod-assembled porous hollow polyhedra have promising applications in various biomedical fields such as the drug and protein delivery.

Highly porous ceramics based on ultralong hydroxyapatite nanowires

For the first time, ultralong hydroxyapatite (HAP) nanowires with lengths longer than 200 μm are used to fabricate highly porous HAP ceramics using palmitic acid spheres as pore formers. The effects of the aspect ratio of HAP and the addition amount of palmitic acid spheres on the formation of HAP porous ceramics are investigated and compared with commercial HAP nanoparticles. The ultralong HAP nanowires can cross-link with each other, leading to much stronger interaction among HAP nanowires than HAP nanoparticles. During the sintering process, although palmitic acid spheres are decomposed at high temperatures, ultralong HAP nanowires can be well preserved and still support the whole porous structure stably, leading to the formation of highly porous HAP ceramics with high biocompatibility. The porosity of the HAP nanowire porous ceramics can be easily tuned. The as-prepared HAP nanowire porous ceramics exhibit good biocompatibility, good performance for cell adhesion and spreading, and cell proliferation. Thus, the as-prepared HAP nanowire porous ceramics are promising for applications in various biomedical fields.