Physicochemical properties and cytocompatibility of radiation-resistant and anti-washout calcium phosphate cement by introducing artemisia sphaerocephala krasch gum.

The anti-washout ability of calcium phosphate cement (CPC) determines the effectiveness of CPC in clinical application. The γ-ray irradiation method often used in the sterilization process of CPC products is easy to degrade some commonly polymer anti-washout agent, which greatly reduces its anti-washout performance. Artemisia sphaerocephala Krasch gum (ASKG) has the potential of radiation resistance and anti-washout, but no one has considered its performance as anti-washout agent of CPC and mechanism of radiation resistance and anti-washout so far. In this study, we report the effect of γ-ray on ASKG and the effectiveness of ASKG for enhancing of radiation resistance and anti-washout ability of CPC, the physical, chemical properties and in vitro cell behaviors of ASKG-CPCs were also investigated. The results showed that addition of ASKG before and after irradiation could significantly enhanced the anti-washout performance of CPC, which is differ from conventional anti-washout agents. Meanwhile, ASKG-CPCs had an excellent injectable property and biocompatibility, and low content of irradiated ASKG could promote bone differentiation well. We anticipate that the radiation-resistant and anti-washout ASKG-CPCs have potential application prospect in orthopaedic surgery.

An immuno-potentiating vehicle made of mesoporous silica-zinc oxide micro-rosettes with enhanced doxorubicin loading for combined chemoimmunotherapy.

Herein, mesoporous silica-zinc oxide (MS-Zn) micro-rosettes with controllable petal thickness were synthesized by a facile one-pot hydrothermal method. MS-Zn loaded with doxorubicin and polyinosinic-polycytidylic acid sodium salt not only significantly inhibits tumor growth but also effectively rejects tumor metastasis in vivo.

Study on MgxSr3-x(PO4)2 bioceramics as potential bone grafts.

Magnesium (Mg) and strontium (Sr), which are essential nutrient elements in the natural bone, positively affect the osteogenic activity even in wide ranges of ion concentrations. However, it remains unknown whether magnesium-strontium phosphates [MgxSr3-x(PO4)2] are potential bone grafts for accelerating bone regeneration. Herein, a serial of MgxSr3-x(PO4)2, including Mg3(PO4)2, Mg2Sr(PO4)2, Mg1.5Sr1.5(PO4)2, MgSr2(PO4)2 and Sr3(PO4)2, were synthesized using a solid-state reaction approach. The physicochemical properties and cell behaviors of MgxSr3-x(PO4)2 bioceramics were characterized and compared with the common bone graft ß-tricalcium phosphate (ß-TCP). The results indicated that various MgxSr3-x(PO4)2 bioceramics differed in compressive strength and in vitro degradation rate. All the MgxSr3-x(PO4)2 bioceramics had excellent biocompatibility. In contrast to ß-TCP, the MgxSr3-x(PO4)2 enhanced alkaline phosphatase activity of mouse bone mesenchymal stem cells (mBMSCs), and inhibited osteoclastogenesis-related gene expression of RAW264.7 cells, but did not enhance osteogenesis-related gene expression of mBMSCs which were treated with osteogenesis induction supplements. However, Mg3(PO4)2 stimulated osteogenesis-related gene expression of mBMSCs without the treatment of osteogenesis induction supplements. This work contributes to the design of bone graft and may open a new avenue for the bone regeneration field.

Improvement in endothelial cell adhesion and retention under physiological shear stress using a laminin-apatite composite layer on titanium.

Apatite (Ap), laminin-apatite composite (L5Ap, L10Ap, L20Ap and L40Ap) and albumin-apatite (AlbAp) composite layers were prepared on titanium (Ti) using a supersaturated calcium phosphate solution supplemented with laminin (0, 5, 10, 20 and 40 µg ml(-1)) or albumin (800 µg ml(-1)). With an increase in the concentrations of laminin in the supersaturated calcium phosphate solutions, the amounts of laminin immobilized on the Ti increased. The number of human umbilical vein endothelial cells (HUVECs) adhered to the laminin-apatite composite layers were remarkably higher than those to the untreated Ti, Ap layer and AlbAp composite layer. The number of cells adhered to the L40Ap was 4.3 times the untreated Ti. Moreover, cells adhered to the laminin-apatite composite layers showed significantly higher cell retention under the physiological shear stress for 1 h and 2 h than those to the untreated Ti, Ap layer and AlbAp composite layer. The number of cells remaining on the L40Ap under the physiological shear stress for 2 h was 9.5 times that of the untreated Ti. The laminin-apatite composite layer is a promising interfacial layer for endothelialization of blood-contacting materials.

Tissue-engineered endothelial cell layers on surface-modified Ti for inhibiting in vitro platelet adhesion.

A tissue-engineered endothelial layer was prepared by culturing endothelial cells on a fibroblast growth factor-2 (FGF-2)-l-ascorbic acid phosphate magnesium salt n-hydrate (AsMg)-apatite (Ap) coated titanium plate. The FGF-2-AsMg-Ap coated Ti plate was prepared by immersing a Ti plate in supersaturated calcium phosphate solutions supplemented with FGF-2 and AsMg. The FGF-2-AsMg-Ap layer on the Ti plate accelerated proliferation of human umbilical vein endothelial cells (HUVECs), and showed slightly higher, but not statistically significant, nitric oxide release from HUVECs than on as-prepared Ti. The endothelial layer maintained proper function of the endothelial cells and markedly inhibited in vitro platelet adhesion. The tissue-engineered endothelial layer formed on the FGF-2-AsMg-Ap layer is promising for ameliorating platelet activation and thrombus formation on cardiovascular implants.

[Antitumor effect of calcium phosphate cement incorporating doxorubicin microspheres].

OBJECTIVE: To investigate the antitumor effect of calcium phosphate cement incorporated with doxorubicin microspheres. METHODS: The absorbance at 490 nm of SaoS-2 cells cultured for 5 days in the media containing the extract of the cement incorporating doxorubicin microspheres was measured using Cell Counting Kit-8. SaoS-2 cells were adjusted to the density of 2x10(7) ml(-1) and injected into the left buttock of nude mouse in the volume of 0.2 ml. The cell suspension (0.1 ml) mixed with an equal volume of the cement extract were injected into the right buttock and on the back of the bilateral ears of nude mice. At 12 days after the cell injection, the tumor tissues were obtained and weighed to calculate the tumor inhibition rate, and the pathological samples were observed with HE staining. RESULTS: The extract of the bone cement containing doxorubicin microspheres showed inhibitory effects on the tumor growth in a dose-dependent manner. The tumor inhibition rate reached 61.0% in high-dose group. Tumor necrosis was found in high dose group, but virtually absent in low-dose group. CONCLUSIONS: CPC containing doxorubicin PLGA microspheres can inhibit tumor cell growth both in vitro and in vivo.