A potential flower-like coating consisting of calcium-phosphate nanosheets on titanium surface

Titanium and its alloys have been widely used as implant materials in bio-medicine.Additionally,surface modification has been utilized to improve the chemical and morphological properties of materials.More specifically,biocoating,especially the calcium-phosphate nano-coating,has been widely used in the research field.In this study,a novel calcium-phosphate nanoflower coating was performed on the titanium surface by a simple approach.This study indicated that the novel calcium-phosphate flower-like coating consisting of calcium-phosphate nanosheets had high surface area,low cytotoxicity as well as promising cell affinity.Hence it could be a potential alternative modification method for titanium.

In vitro and in vivo evaluations of Mg-Zn-Gd alloy membrane on guided bone regeneration for rabbit calvarial defect

To develop a biodegradable membrane with guided bone regeneration(GBR),a Mg-2.0Zn-1.0Gd alloy(wt.%,MZG)membrane with Ca-P coating was designed and fabricated in this study.The microstructure,hydrophilicity,in vitro degradation,cytotoxicity,antibacterial effect and in vivo regenerative performance for the membrane with and without Ca-P coating were evaluated.After coating,the membrane exhibited an enhance hydrophilicity and corrosion resistance,showed good in vitro cytocompatibility upon MC3T3E-1 cells,and exhibited excellent antibacterial effect against E.coli,Staphylococcus epidermis and Staphylococcus aureus,simultaneously.In vivo experiment using the rabbit calvarial defect model confirmed that Ca-P coated MZG membrane underwent progressive degradation without inflammatory reaction and significantly improved the new bone formation at both 1.5 and 3 months after the surgery.All the results strongly indicate that MZG with Ca-P coating have great potential for clinical application as GBR membranes.

Inorganic phosphate in the development and treatment of cancer:A Janus Bifrons?

Inorganic phosphate(Pi) is an essential nutrient to living organisms. It is required as a component of the energy metabolism,kinase/phosphatase signaling and in the formation and function of lipids,carbohydrates and nucleic acids and,at systemic level,it plays a key role for normal skeletal and dentin mineralization. Pi represents an abundant dietary element and its intestinal absorption is efficient,minimally regulated and typically extends to approximately 70%. Maintenance of proper Pi homeostasis is a critical event and serum Pi level is maintained within a narrow range through an elaborate network of humoral interactions and feedback loops involving intestine,kidney,parathyroid gland and bone,and depends on the activity of a number of hormones,including parathyroid hormone,1,25-dihydroxy vitamin D,and fibroblast growth factor 23 as major regulators of Pi homeostasis. Notably,Pi intake seemingly continues to increase as a consequence of chronic high-phosphorus(P) diets deriving from the growing consumption of highly processed foods,especially restaurant meals,fast foods,and convenience foods. Several recent reports have generated significant associations between high-P intake or high-serum Pi concentration and morbidity and mortality. Many chronic diseases,including cardiovascular diseases,obesity and even cancer have been proposed to be associated with high-P intakes and high-serum Pi concentrations. On the other hand,there is also evidence that Pi can have antiproliferative effects on some cancer cell types,depending on cell status and genetic background and achieve additive cytotoxic effects when combined with doxorubicin,illustrating its potential for clinical applications and suggesting that up-regulating Pi levels at local sites for brief times,might contribute to the development of novel and cheap modalities for therapeutic intervention in some tumours. Overall,the influence of Pi on cell function and the possible relationship to cancer have to be fully understood and investigated further.

Electrodeposition of calcium phosphate onto polyethylene terephthalate artificial ligament enhances graft-bone integration after anterior cruciate ligament reconstruction

It is a big challenge to develop a polyethylene terephthalate(PET)artificial ligament with excellent osteogenetic activity to enhance graft-bone integration for ligament reconstruction.Herein,we evaluated the effect of biomineralization(BM)and electrodeposition(ED)method for depositing calcium-phosphate(CaP)on the PET artificial ligament in vitro and in vivo.Scanning electron microscopy and energy-dispersive X-Ray spectrometer mapping analysis revealed that the ED-CaP had more uniform particles and element distribution(Ca,P and O),and thermogravimetric analysis showed there were more CaP on the PET/ED-CaP than the PET/BM-CaP scaffold.Moreover,the hydrophilicity of PET scaffolds was significantly improved after CaP deposition.In vitro study showed that CaP coating via BM or ED method could improve the attachment and proliferation of MC3T3-E1 cells,and ED-CaP coating significantly increased osteogenic differentiation of the cells,in which the Wnt/β-catenin signaling pathway might be involved.In addition,radiological,histological and immunohistochemical results of in vivo study in a rabbit anterior cruciate ligament(ACL)reconstruction model demonstrated that the PET/BM-CaP and PET/ED-CaP scaffolds significantly improved graft-bone integration process compared to the PET scaffold.More importantly,larger areas of new bone ingrowth and the formation of fibrocartilage tissue were observed at 12 weeks in the PET/ED-CaP group,and the biomechanical tests showed increased ultimate failure load and stiffness in PET/ED-CaP group compared to PET/BM-CaP and PET group.Therefore,ED of CaP is an effective strategy for the modification of PET artificial ligament and can enhance graft-bone integration both in vitro and in vivo.