•Obtaining PVA gel by the crosslinking of borate glass and freeze-thawing method simultaneously•Chemical reaction between borate glass and PVA•Release control of borate•Porous structure after freeze-drying•Potential drug carrierBorate Bioactive Glass(BG)/PVA hydrogel was prepared by the combination of chemical cross - linking method and physical freeze-thawing method. BG powder and PVA solution were mixed at different BG/PVA weight ratios of 0.05, 0.10, 0.15 and 0.20 then went through freeze-thawing cycles to form the hydrogel. The BG/PVA hydrogels were characterized by swelling, degradability, drug delivery performance, mechanical strength, attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR) and field emission scanning electron microscope with energy dispersive spectrometer (FESEM-EDS). The compressive strength and tensile strength of BG/PVA were improved compared to the pure PVA hydrogel. When immersed in PBS, all the hydrogels showed good swelling properties and the concentration of B released in PBS was smaller than 100 ppm due to the reaction with PVA and the release of functional ions could be detected by atomic emission spectrometer (ICP-AES). Therefore, this hydrogel showed excellent properties in both borate control and crosslinking.

•Agglutination effect of Cu2+ and charge balance of agglomerate lead to more stable glass.•Lower degradability and lower ions release were found in BG-Cu scaffolds.•Excellent angiogenesis and sustain Cu2+ release were endowed by doping Cu.Copper doped borosilicate glasses (BG–Cu) were studied by means of FT-IR, Raman, UV–vis and NMR spectroscopies to investigate the changes that appeared in the structure of borosilicate glass matrix by doping copper ions. Micro-fil and immunohistochemistry analysis were applied to study the angiogenesis of its derived scaffolds in vivo. Results indicated that the Cu ions significantly increased the B–O bond of BO4 groups at 980 cm−1, while they decrease that of BO2O− groups at 1440–1470 cm−1 as shown by Raman spectra. A negative shift was observed from 11B and 29Si NMR spectra. The 11B NMR spectra exhibited a clear transformation from BO3 into BO4 groups, caused by the agglutination effect of the Cu ions and the charge balance of the agglomerate in the glass network, leading to a more stable glass network and lower ions release rate in the degradation process. Furthermore, the BG–Cu scaffolds significantly enhanced blood vessel formation in rat calvarial defects at 8 weeks post-implantation. Generally, it suggested that the introduction of Cu into borosilicate glass endowed glass and its derived scaffolds with good properties, and the cooperation of Cu with bioactive glass may pave a new way for tissue engineering.

•The pH-sensitive composite alginate beads incorporating Sr-doped HA microspheres (SrHA) have been prepared.•The incorporation of the SrHA enhanced the drug loading and release properties of the alginate microspheres.•The composite microspheres showed excellent osteogenic effect by releasing osteogenic Sr ions.The strontium-substituted hydroxyapatite microspheres (SrHA) incorporated alginate composite microspheres (SrHA/Alginate) were prepared via adding SrHA/alginate suspension dropwise into calcium chloride solution, in which the gel beads were formed by means of crosslinking reaction. The structure, morphology and in vitro bioactivity of the composite microspheres were studied by using XRD, SEM and EDS methods. The biological behaviors were characterized and analyzed through inductively coupled plasma optical emission spectroscopy (ICP-OES), CCK-8, confocal laser microscope and ALP activity evaluations. The experimental results indicated that the synthetic SrHA/Alginate showed similar morphology to the well-known alginate microspheres (Alginate) and both of them possessed a great in vitro bioactivity. Compared with the control Alginate, the SrHA/Alginate enhanced MC3T3-E1 cell proliferation and ALP activity by releasing osteoinductive and osteogenic Sr ions. Furthermore, vancomycin was used as a model drug to investigate the drug release behaviors of the SrHA/Alginate, Alginate and SrHA. The results suggested that the SrHA/Alginate had a highest drug-loading efficiency and best controlled drug release properties. Additionally, the SrHA/Alginate was demonstrated to be pH-sensitive as well. The increase of the pH value in phosphate buffer solution (PBS) accelerated the vancomycin release. Accordingly, the multifunctional SrHA/Alginate can be applied in the field of bioactive drug carriers and bone filling materials.

Multifunctional biocompatible scaffolds with enhanced osteogenic capacity coupled with magnetic and magnetothermal properties are of great interest for the repair of large bone defects resulting from the resection of tumors. In the present study, we created borosilicate bioactive glass (BG) scaffolds loaded with varying amounts (5–15 wt%) of Fe3O4 magnetic nanoparticles (MNPs) and evaluated their performance in vitro and in vivo. The incorporation of MNPs endowed scaffolds with excellent magnetic, controlled magnetothermal properties and higher mechanical capacity. The MNP-loaded scaffolds were not toxic to human bone marrow-derived stem cells (hBMSCs) cultured on the scaffolds in vitro. The alkaline phosphatase activity and the osteogenic gene expression of the hBMSCs increased with increasing amount of MNPs in the scaffolds. When implanted in rat calvarial defects for 8 weeks, the scaffolds loaded with 15 wt% MNPs showed a significantly better capacity to regenerate bone when compared to the scaffolds without the MNPs. These MNP-loaded BG scaffolds are promising implants for regenerating bone in defects resulting from tumor resection.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editors-in-Chief.The article duplicates significant parts of a paper that had already appeared in Journal of Materials Chemistry B, 48 (2014) 8547–8557. DOI: http://dx.doi.org/10.1039/C4TB01355G. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Biocompatible synthetic scaffolds with enhanced osteogenic and angiogenic capacity are of great interest for the repair of large (critical size) bone defects. In this study, we investigated an approach based on the controlled delivery of copper (Cu) ions from borate bioactive glass scaffolds for stimulating angiogenesis and osteogenesis in a rodent calvarial defect model. Borate glass scaffolds (pore size = 200–400 μm) doped with varying amounts of Cu (0–3.0 wt% CuO) were created using a polymer foam replication technique. When immersed in simulated body fluid (SBF) in vitro, the scaffolds released Cu ions into the medium at a rate that was dependent on the amount of Cu in the glass and simultaneously converted to hydroxyapatite (HA). At the concentrations used, the Cu in the glass was not cytotoxic to human bone marrow derived stem cells (hBMSCs) cultured on the scaffolds and the alkaline phosphatase activity of the hBMSCs increased with increasing Cu in the glass. When implanted in rat calvarial defects for 8 weeks, the scaffolds doped with 3 wt% CuO showed a significantly better capacity to stimulate angiogenesis and regenerate bone when compared to the undoped glass scaffolds. Together, these results indicate that the controlled delivery of Cu ions from borate bioactive glass implants is a promising approach in healing bone defects.

Hybrid mesoporous silica nanoparticles (MSNs), which were synthesized using the co-condensation method and engineered with unique redox-responsive gatekeepers, were developed for studying the glutathione-mediated controlled release. These hybrid nanoparticles constitute a mesoporous silica core that can accommodate the guests (i.e., drug, dye) and the PEG shell that can be connected with the core via disulfide-linker. Interestingly, the PEG shell can be selectively detached from the inner core at tumor-relevant glutathione (GSH) levels and facilitate the release of the encapsulated guests at a controlled manner. The structure of the resulting hybrid nanoparticles (MSNs-SS-mPEG) was comprehensively characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and nitrogen adsorption/desorption isotherms analysis. The disulfide-linked PEG chains anchored on MSNs could serve as efficient gatekeepers to control the on–off of the pores. Compared with no GSH, fluorescein dye as the model drug loaded into MSNs showed rapid release in 10 mM GSH, indicating the accelerated release after the opening of the pores regulated by GSH. Confocal microscopy images showed a clear evidence of the dye-loaded MSNs-SS-mPEG nanoparticles endocytosis into MCF-7 cells and releasing guest molecules from the pore inside cells. Moreover, in vitro cell viability test using MTT assay indicated that MSNs-SS-mPEG nanoparticles had no obvious cytotoxicity. These results indicate that MSNs-SS-mPEG nanoparticles can be used in the biomedical field.Keywords: controlled release; cytotoxicity; mesoporous silica nanoparticles (MSNs); MSNs-SS-PEG nanoparticles; PEG gatekeeper; reduction-sensitive;

Multifunctional biocompatible scaffolds with enhanced osteogenic capacity coupled with magnetic and magnetothermal properties are of great interest for the repair of large bone defects resulting from the resection of tumors. In the present study, we created borosilicate bioactive glass (BG) scaffolds loaded with varying amounts (5–15 wt%) of Fe3O4 magnetic nanoparticles (MNPs) and evaluated their performance in vitro and in vivo. The incorporation of MNPs endowed scaffolds with excellent magnetic, controlled magnetothermal properties and higher mechanical capacity. The MNP-loaded scaffolds were not toxic to human bone marrow-derived stem cells (hBMSCs) cultured on the scaffolds in vitro. The alkaline phosphatase activity and the osteogenic gene expression of the hBMSCs increased with increasing amount of MNPs in the scaffolds. When implanted in rat calvarial defects for 8 weeks, the scaffolds loaded with 15 wt% MNPs showed a significantly better capacity to regenerate bone when compared to the scaffolds without the MNPs. These MNP-loaded BG scaffolds are promising implants for regenerating bone in defects resulting from tumor resection.

Biocompatible synthetic scaffolds with enhanced osteogenic and angiogenic capacity are of great interest for the repair of large (critical size) bone defects. In this study, we investigated an approach based on the controlled delivery of copper (Cu) ions from borate bioactive glass scaffolds for stimulating angiogenesis and osteogenesis in a rodent calvarial defect model. Borate glass scaffolds (pore size = 200–400 μm) doped with varying amounts of Cu (0–3.0 wt% CuO) were created using a polymer foam replication technique. When immersed in simulated body fluid (SBF) in vitro, the scaffolds released Cu ions into the medium at a rate that was dependent on the amount of Cu in the glass and simultaneously converted to hydroxyapatite (HA). At the concentrations used, the Cu in the glass was not cytotoxic to human bone marrow derived stem cells (hBMSCs) cultured on the scaffolds and the alkaline phosphatase activity of the hBMSCs increased with increasing Cu in the glass. When implanted in rat calvarial defects for 8 weeks, the scaffolds doped with 3 wt% CuO showed a significantly better capacity to stimulate angiogenesis and regenerate bone when compared to the undoped glass scaffolds. Together, these results indicate that the controlled delivery of Cu ions from borate bioactive glass implants is a promising approach in healing bone defects.