In recent years, zirconia ceramic, as a preferential choice for teeth restorations, is used as fixed partial dentures and implants due to its excellent mechanical properties, favorable biocompatibility and aesthetic properties, thus significantly shortening the performance life and seriously damaging the reliabilities. However, zirconia ceramic easily occurs low temperature degradation (LTD) of t-m transformation in humid environments. This paper illustrated the characteristics, mechanism and kinetics of LTD, as well as the conventional characterization methods of LTD phenomena and new methods such as optical coherence tomography and focused ion beam. It is also shown the main factors affecting the aging phenomenon, and emphasized the inhibition methods of LTD. By developing materials system and improving processing technology to enhance the strength, fracture toughness of zirconia and to solve the LTD of zirconia, and to meet the needs of people for their health functionalization, zirconia ceramic will be widely applied in the dental restoration field.

Porous bioceramic scaffolds, which possess attractive biocompatibility, ability to guide tissue regeneration and porous surface morphologies and channels beneficial to ingrowth of new born tissues, have seized increasing attentions and been widely applied in the field of hard tissue restoration. Whereas, the weak osteoinductive activity, monotonous biological function and poor mechanical property have restrained the therapeutic efficacy and wider application of bioceramic scaffolds. In view of this, we intended to introduce the existing modification methods of bioceramic scaffolds, including the surface modification with functional coating, construction of surface micro-/nano- structures, functional element doping and enhancement of mechanical property, along with the state of the research progresses in the improvement of biocompatibility, bone defect restoration, drug delivery, tumor therapy, and antibacterial capacity of multifunctional bioceramic scaffolds. In addition, potential research directions and applications of functionally modified bioceramic scaffolds are prospected to provide references for the related exploration afterwards.

An injectable composite bone cement was fabricated by employing Sol-Gel derived mesoporous borosilicate bioactive glass spheres (MBGS) as solid phase and sodium alginate (SA) solution as liquid phase. The effects of the B₂O₃/SiO₂ ratio in MBGS on its textural properties and workability, compressive strength and bioactivity of bone cement were characterized. It is found that with the increase of boron content, the specific surface area of MBGS increases from 161.71 m²/g to 214.28 m²/g, and the average pore size and total pore volume also increase, which accelerates the Ca²⁺ release and rapidly crosslinks MBGS and SA. Thus, the workability, mechanical property and in vitro mineralization of bone cement are significantly improved, as the setting time is shortened from 21 min to 9 min and the compressive strength is enhanced from 3.4 MPa to 4.1 MPa. Comprehensive performance of all aspects, BC-30 bone cement showing good workability, mechanical properties and in vitro mineralization ability, displays the optimal component. Therefore, improving the textural properties of MBGS is an effective method to enhance the workability, compressive strength and bioactivity of composite bone cement.

Porous microsphere cell microcarrier with macroporous structure can not only amplify cells in vitro, but also serve as cell delivery tools to deliver cells to damaged tissues by injection. Bioglass (BG) is an inorganic material with excellent biological activity, however, it is difficult to directly prepare microcarriers with macroporous structure. Therefore, in this study, a BG/poly-lactic acid (PLA) porous microspheres was prepared by double emulsion method. The morphology and structure of the microsphere were characterized by SEM, and the load of BG in the microsphere was characterized by thermo gravimetric analysis and its ion release was detected by ICP. Cell proliferation experiments showed that cells could adhere and grow on the surface and inside of the microspheres. The results show that the microsphere with interconnected open-pore microstructure is suit for cell adhesion and proliferation. Bioglass can promote cell proliferation in the microspheres and the obtained BG/PLA composite microsphere has great potential applications in tissue engineering.

The CaO-SiO₂-P₂O₅ bioglass (BG) microspheres with good bioactivity and osteoconductivity have been extensively studied for bone tissue engineering. Traditional melting method for preparing BG powders is high energy consumption, and difficult to control the morphology of BG. While Sol-Gel technique for BG preparation requires a large amount of organic solvent, long preparation period and low mass production. For the rapid and scalable preparation of BG microspheres with controllable morphology, particle size and chemical composition, an efficient strategy of spray drying of precursor solution was proposed in this study, and the effects of process parameters including inlet air volume, precursor solution concentration and feed rate on the particle size of BG microspheres, and the effect of chemical composition on the apatite formation ability of BG microspheres in vitro were investigated. The results showed that the particle sizes of BG microspheres via spray drying could be controlled below 40 μm, and the particle sizes of BG microspheres increased with the concentration of precursor solution, and decreased with the increase of inlet air volume, but the feed rate has a slight effect on the particle size of the microspheres. On the other hand, BG microspheres with different chemical compositions had good ability to induce apatite formation in vitro, and it increased with the increase of CaO content. Therefore, spray drying method would be promising for rapid and scalable preparation of BG microspheres.

Due to high stability and sensitivity, inorganic nanomaterials with enzyme-like activity have brilliant application prospects. Tuning the enzyme-like activity plays great significance for promoting the development of nanozymes. In this work, Pt-Au dendritic nanoparticles (Pt-Au DNPs) with good uniformity and stability were synthesized by a simple liquid phase reduction method, and used to colorimetrically detect ascorbic acid (AA) by using their oxidase-like activity to catalyze the oxidation of TMB (3,3′,5,5′-tetramethylbenzidine). The oxidase-like activity was found to be highly influenced by the composition and structure of Pt-Au dendritic nanoparticles, and the relationship between kinetic parameters and nanoparticle structure was investigated. Quantitative analysis of ascorbic acid in the 1-15 μmol/L range was performed with good linear relationship, and the detection limit was 78 nmol/L. At the same time, it’s found that continuous reaction would reduce the catalytic performance of Pt-Au DNPs, but still has the potential to be reused, which is not common. Data from this research not only suggests a method for synthesizing Pt-Au DNPs, but also shows its potential for AA analysis in biological samples.

Overhigh temperature can induce inflammation and heat radiation damage to normal tissues around the tumor. Therefore, the development of a magnetic material that can achieve high mortality of tumor cells at relatively low temperatures (e.g. 43 ℃) is critical for the clinical application of magnetocaloric therapy. This study focuses on the goal of low-temperature, safe, and effective magnetic thermotherapy. The liquid-solid phase transition material polylactic acid-glycolic acid (PLGA) approved by the FDA, is selected as raw material and superparamagnetic iron oxide nanoparticles prepared by a one-step mild reduction method are loaded to achieve magnetic resonance imaging and magnetic heating. Meanwhile, a small molecule inhibitor of heat shock protein HSP90, i.e, epigallocatechin gallate (EGCG), encapsulated in PLGA, could inhibit the body’s thermal protection function and achieve the purpose of killing tumor cells at lower temperatures. In vitro results indicated that the prepared superparamagnetic iron oxide nanoparticles not only have good T₂-weighted imaging performance, but also show excellent magnetothermal transformation performance. More details, when the obtained PLGA/Fe₃O₄/EGCG biocomposite was controlled to heated up to 43 ℃ for 40 min under an alternating magnetic field, around 70% of tumor cell could be killed, exhibiting promising potential for low-temperature magnetothermal treatment of tumor. Such novel injectable magnetic thermal phase transition material may provide new idea and material support for the treatment of osteosarcoma.

Ultralong hydroxyapatite nanowires (UHANWs) exhibit great potential in constructing different kinds of biomaterials such as the highly flexible biomedical paper and elastic porous scaffolds for various biomedical applications. Moreover, strontium (Sr), a trace element in human body, plays an important role in bone metabolism. In this study, Sr-doped UHANWs (Sr-UHANWs) with various Sr/(Sr+Ca) molar ratios have been successfully prepared by the one-step oleate precursor solvothermal method. The effects of the Sr/(Sr+Ca) molar ratio on the morphology and crystal phase of the Sr-UHANWs were investigated. The as-prepared Sr-UHANWs exhibit high flexibility and ultralong 1D nanostructure. Moreover, the energy dispersive spectroscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy of the as-prepared samples reveal that Sr element has been successfully incorporated in UHANWs. The preparation method developed in this work may be suitable for the synthesis of Sr-UHANWs with Sr/(Sr+Ca) molar ratios ranging from 0 to 100 %, which may enlarge the biomedical applications of UHANWs such as bone and teeth defect repair.

Organic-inorganic hybrid mesoporous organosilica has gained more attention in biomedicine due to its high surface area, mesoporous channels, functional framework, and high drug loading capacity. In this study, disulfide- bridged hybrid mesoporous organosilica nanoparticles (MONs) as nanocarriers were employed to construct a nanosystem (ICG/DOX-MONs@DNA₂₀) for delivering drugs and photothermal agents, in which DNA molecules as “switches” were modified on the surface of MONs to control drug release. The results showed that the ICG/DOX-MONs@DNA₂₀ nanosystem could increase the temperature to above 43 ℃ for photothermal therapy with near-infrared (NIR) laser irradiation. On the other hand, the ICG/DOX-MONs@DNA₂₀ nanosystem exhibited a very slow release of DOX (12.3% in 6 h) at 37 ℃, but a rapid release of DOX (52.4% in 6 h) occurred at 43 ℃. Cell culture experiments indicated that the nanosystem can be internalized by HeLa cells, and exhibited an enhanced therapeutic efficacy of synergistic chemo- and photothermal therapy. Hence, the ICG/DOX-MONs@DNA₂₀ nanosystem might be promising for synergistic chemo- and photo-thermal tumor therapy.

To reduce the cost of HA and improve degradation performance of HA, oyster shells were used as raw materials to prepare CaCO₃/ hydroxyapatite (HA) composite materials by a hydrothermal method. Phase analysis and SEM/TEM observation revealed that as-prepared CaCO₃/HA composites had a morphology of HA nanoparticles growing on the lamellar CaCO₃. Three kinds of CaCO₃/HA composites (20%HA、40%HA、60%HA) with HA content of 20%, 40% and 60% were prepared by controlling the proportion of calcium and phosphorus. The actual content of HA in three obtained different composites, determined by ICP, were 17.52%, 34.30% and 43.24%, respectively. With the increase of HA content, the specific surface area and thermal stability of CaCO₃/HA composite are improved. Samples were immersed in PBS simulated body fluid for 14 d to evaluate their in vitro degradation ability. The results showed that degradation rates of three kinds of composites with different HA contents (20%HA, 40%HA and 60%HA) were 15.2%, 12.0% and 10.8%, respectively. The degradation rate decreased with the increase of HA proportion in the composite. All data indicates that the hydrothermal synthesis of CaCO₃/HA composite can control the conversion degree of HA and then adjust the degradation rate of CaCO₃/HA composite by designing the ratio of calcium and phosphorus elements, which have potential application in orthopedics.

In recent years, zinc-based biodegradable materials have gained significant attention due to their desirable biodegradation rate compared with other extensively explored biodegradable metals, such as magnesium and iron. However, the long-term corrosion behavior of zinc in simulated body fluid remain unclear. In this study, we performed a 56 d immersion test to reveal the long-term evolution of corrosion behavior of zinc in Ringer’s solution using electrochemical methods and surface analysis. The results showed that the corrosion rate of Zn calculated from current density ranged from 0.06 to 0.1 mm/a during the immersion. Its corrosion rate, determined by weight loss method, was from 0.3 mm/a to 0.5 mm/a. The corrosion products were mainly composed of Zn₅(CO₃)₂(OH)₆ and CaCO₃. These products were firm, rod- and block-like formed on Zn surface, and gradually accumulated with increase of immersion time. Its surface morphology after removing corrosion products exhibited increasing sizes of corrosion pits and grooves with increase of immersion time. And width of the corrosion pits and grooves was about 10 μm after 42 d immersion. This study provides a guideline for the further surface modification and biomedical applications of Zn-based materials in terms of biodegradation profile.

Alum has an excellent safety record and is the only licensed inorganic adjuvant for human vaccines. However, the exploration of alum nanosheets as chemotherapy drug delivery system, especially the clarification about the relationship between structures and drug loading properties, is totally insufficient. Herein, aluminum hydroxides (AlOOH) nanosheets with tunable specific surface area and pore size were synthesized by adjusting the synthesis time in the presence of triblock copolymers. The obtained materials exhibited the highest surface area about 470 m ²/g. The structure-dependent chemotherapy drug loading capability for AlOOH nanosheets was observed: the higher specific surface area and pore size are, the higher amount of chemotherapy drug is loaded. AlOOH nanosheets loaded with doxorubicin showed a pH-dependent sustained release behavior with quick release in low pH about 5 and slow release in pH around 7.4. Doxorubicin-loaded AlOOH nanosheets exhibited much higher cancer cellular uptake efficiency than that in free form by flow cytometry. Moreover, doxorubicin-loaded AlOOH nanosheets with high specific surface area showed an increased cellular uptake efficiency and enhanced ratios of apoptosis and necrosis, compared with those showing low specific surface area. Therefore, AlOOH nanosheets are promising materials as chemotherapy drug delivery system.

To develop a new kind of non-viral inorganic gene vector, embedded dual-mesoporous silica spheres (EDMSNs) was modified with polyethyleneimine (PEI) or 3-aminopropyltriethoxysilane (APTMS). Then gene loading and transfection ability of the obtained EDMSNs-PEI and EDMSNs-NH₂ was tested by choosing the pCMV-EGFP-N1 plasmids (pDNA) as a gene model. Particle morphologies, particle sizes, zeta potentials, and pore structure parameters of EDMSNs-NH₂ and EDMSNs-PEI were characterized by transmission electron microscopy, dynamic light scattering and nitrogen adsorption-desorption. Both EDMSNs-NH₂ and EDMSNs-PEI display obvious dual-mesoporous structure and well-defined spherical morphology. Average dynamic sizes of EDMSNs-NH₂ and EDMSNs-PEI are 343.2 and 338.9 nm, while zeta potentials of EDMSNs-NH₂ and EDMSNs-PEI are +18 and +43 mV, respectively. The results of gel electrophoresis, CCK-8 assay, and fluorescence microscope show that the pDNA loading amount of EDMSNs-PEI is 8%, much higher than that (1%) of EDMSNs-NH₂. In addition, EDMSNs-PEI exhibits lower cytotoxicity than that of pure PEI polymers and lipofectamine2000. When the mass ratio of EDMSNs- PEI/pDNA is 33 : 1, the transfection rate of the 293T cells by EDMSNs-PEI/pDNA reaches a maximum at 72 h. In conclusion, EDMSNs-PEI, compared with EDMSNs-NH2, has a higher positive potential and pDNA loading capacity, which can be used as a promising non-viral inorganic gene vector for the treatment of diseases such as malignant glioma.

Zirconia is a kind of prospective hard tissue implant materials, which possesses superior mechanical properties and excellent biocompatibilities. To promote the stable osseointegration between Zirconia implants and tissue, zirconia-toughened trace Sr-, Si- and F- co-doped hydroxyapatite (ZrO₂-DHA) was coated by plasma spraying on zirconia. The phase composition and structure of coatings were characterized, and the mechanical properties and in vitro biological properties were investigated. The results show that co-doping of trace Sr, Si and F enhances the biological properties of coatings on adhesion and differentiation of osteoblasts through the signal transduction pathway of osteogenic differentiation. All of ZrO₂-DHA coatings promote the cell viability and gene expression in osteogenic differentiation of MC3T3-E1. On the 7th day of cell culture, the relative expression levels of Alp and Col-I in the ZrO₂-DHA coating containing 70% DHA (7DHA) were about 2.8 times and 2.3 times higher than those in the ZrO₂ substrate group, respectively. Mechanical properties of ZrO₂-DHA coatings are improved with the increment of zirconia ratio. Hardness of DHA coating and 7DHA coating are 250.8 and 313.8HV respectively and their bond strength are 25.1 and 31.8 MPa, respectively. 7DHA coatings with network structure possess both excellent mechanical and biological performance for the implant coating application.

Titanate nanofibers were prepared on titanium mesh by alkali-heat treatment, and calcium phosphate coating was fabricated on the porous titanate nanofibers by electrochemical deposition technology. Then hBMP-2 was introduced into the coating by different methods to improve its osteointegration and bioactivity. Three kinds of composite coatings modified by hBMP-2 were prepared (TmhB, TmHedhB and TmHhBed). Surface morphology, chemical composition, phase composition and hBMP-2 amounts and hBMP-2 release performance of the composite coatings were characterized by SEM, ATR-FTIR, XRD, and hBMP-2 ELISA kit, respectively. Results showed that all of the coatings display porous fiber structure, calcium phosphate phase in TmHedhB and TmHhBed samples was hydroxyapatite (HA), and bead-like HA particles formed on the surface of titanate nanofibers. Protein adsorption experiments showed that introduction of bead-like HA phase increased the hBMP-2 adsorption on the composite coatings, and composite coatings prepared by electrochemical co-deposition technique further enhanced hBMP-2 adsorption up to 886 ng/mg, which were supported hBMP-2 sustained release within 6-48 h.

Aspirin/layered double hydroxides composite (A-LDHs) and aspirin/layered double hydroxide-nanosheets composite (A-LDHs-NS) were prepared by intercalation and exfoliation-recombination, respectively. Their morphology, drug loading property and drug loading mode of the composites were characterized by XRD, SEM, TG-DTG, and FT-IR. The releasing performances of aspirin from A-LDHs and A-LDHs-NS in the phosphate buffer solutions with different pH conditions were investigated. The results show that the typical lamellar structures are hold in as-prepared LDHs and LDHs-NS. The larger specific surface area (187 m ²·g ^-1) of LDHs-NS, the more aspirins are loaded on its surface, among which the max drug loading is 1.178 mmol·g ^-1. Its releasing process lasts for more than 1440 min, much longer than 20 min of the control materials, showing excellent sustained-releasing performance. This performance may because of the strong interaction between aspirin and LDHs-NS. Moreover, the sustained releasing performance is stronger at pH 7.4 than that at pH 4.8. All data from this study provides a reference for wider application of this kind of two-dimensional materials in biomedicine.

Titanium and its alloys have been wildly used as bone implants. However, it is still facing a severer issue: implant related infections due to the lack of antibacterial ability. Copper (Cu) has good antibacterial ability and can be used to improve the anti-infection capability of titanium. In this study, three kinds of Ti samples with different contents of Cu in the modified layer were prepared by plasma immersion ion implantation (PIII) technology, and their responses to bacteria and cells were explored in vitro. The results showed that the sample with low Cu content at the surface could promote the proliferation of rat bone marrow mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs) but not inhibit the proliferation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). As the implantation time extends, antibacterial ability of the samples with high Cu content at the surface was significantly enhanced, and no obvious cytotoxicity was observed. Therefore, it is possible to acquire a balance between antibacterial ability and biocompatibility of Ti by controlling the contents of Cu in the modified layer.