Cuilian Tao

Three-dimensional printed strontium-containing mesoporous bioactive glass scaffolds for repairing rat critical-sized calvarial defects.

The development of a new generation of biomaterials with high osteogenic ability for fast osseointegration with host bone is being intensively investigated. In this study, we have fabricated three-dimensional (3-D) strontium-containing mesoporous bioactive glass (Sr-MBG) scaffolds by a 3-D printing technique. Sr-MBG scaffolds showed uniform interconnected macropores (∼400μm), high porosity (∼70%) and enhanced compressive strength (8.67±1.74MPa). Using MBG scaffolds as a control, the biological properties of Sr-MBG scaffolds were evaluated by apatite-forming ability, adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteoblast-like cells MC3T3-E1. Furthermore, Sr-MBG scaffolds were used to repair critical-sized rat calvarial defects. The results showed that Sr-MBG scaffolds possessed good apatite-forming ability and stimulated MC3T3-E1 cell proliferation and differentiation. Importantly, the in vivo results revealed that Sr-MBG scaffolds had good osteogenic capability and stimulated new blood vessel formation in critical-sized rat calvarial defects within 8 weeks. Therefore, 3-D printed Sr-MBG scaffolds with favorable pore structure and high osteogenic ability have more potential applications in bone regeneration.

DNA-capped Fe3O4/SiO2 magnetic mesoporous silica nanoparticles for potential controlled drug release and hyperthermia

We proposed a strategy to construct DNA-capped Fe3O4/SiO2 magnetic mesoporous silica (MMS) nanoparticles for potential temperature controlled drug release and magnetic hyperthermia. Drug release behavior, magnetic heating capacity, in vitro cytotoxicity, and cell uptake of the MMS-based nanocarriers were evaluated. The results showed that the DOX/MMS–NH2–dsDNA complexes could release DOX fast at 50 °C, but very slow at 37 °C. Also, MMS-based nanocarriers could efficiently generate heat upon exposure to an alternating magnetic field due to the superparamagnetic behavior. Furthermore, the MMS–NH2–dsDNA complexes could be effectively taken up by murine breast cancer 4T1 cells, and negligible cytotoxicity of the MMS–NH2–dsDNA complexes has been observed. Therefore, DNA-capped MMS nanoparticles had potential for cancer therapy with temperature controlled drug release and magnetic hyperthermia.

Substitutions of strontium in mesoporous calcium silicate and their physicochemical and biological properties

Calcium silicate (Ca-Si) based bioceramics have been regarded as a potential bioactive materials for bone tissue regeneration. In this study, we have successfully prepared ordered mesoporous strontium (Sr)-substituted CaSiO3 (Sr-CaSiO3) materials by using a triblock copolymer (P123) as a structure-directing agent. The microstructure and porosity of mesoporous Sr-CaSiO3 materials were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and the N2 adsorption-desorption technique. The substitution of Sr for Ca in mesoporous CaSiO3 did not change the mesoporous structure, but the surface area and pore volume decreased with increasing Sr substitution. The effects of the Sr substitution on the physiochemical and biological properties of mesoporous CaSiO3 materials were evaluated by the ion dissolution, apatite-forming ability, proliferation and alkaline phosphatase (ALP) activity of osteoblast-like MC3T3-E1 cells. The results showed that the increasing Sr substitution decreased the dissolution rate of Ca and Si ions from mesoporous CaSiO3 materials and enhanced the ability to stabilize the pH environment. Mesoporous Sr-CaSiO3 materials have a similar apatite-forming ability to mesoporous CaSiO3 material, and stimulated the proliferation and ALP activity of MC3T3-E1 cells. Furthermore, using gentamicin as a model drug, mesoporous Sr-CaSiO3 materials exhibited a sustained drug release property which could be used in local drug delivery therapy. Furthermore, the drug release rate decreased to some extent with increasing Sr substitution in mesoporous CaSiO3 materials. Therefore, mesoporous Sr-CaSiO3 materials have more potential for application in bone tissue regeneration.

Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials

Abstract We have prepared multifunctional magnetic mesoporous Fe–CaSiO3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO3 materials were investigated. Mesoporous Fe–CaSiO3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO3 materials, mesoporous Fe–CaSiO3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia.

Preparation and Characterization of Magnetic Mesoporous Bioactive Glass/Carbon Composite Scaffolds

The magnetic Fe-MBG/C composite scaffolds with enhanced mechanical strength and multifunctionality have been successfully prepared. The study showed that the Fe-MBG/C composite scaffolds with the porosity of ca. 80% had interconnected macropores (200–500 µm) and mesopores (3.7–4.4 nm) and significantly enhanced the compressive strength compared to the pure MBG scaffolds. Importantly, the Fe-MBG/C composite scaffolds exhibited good bioactivity and sustained drug release property. At the same time, the Fe-MBG/C composite scaffolds could generate heat to raise the temperature of surrounding environment in an alternating magnetic field due to their superparamagnetic behavior. Therefore, the magnetic Fe-MBG/C composite scaffolds could form a multifunctional platform with bone regeneration, magnetic hyperthermia, and local drug delivery and have more potential for use in the regeneration of the critical-sized bone defects caused by bone tumors.

Magnetic mesoporous silica nanoparticles for CpG delivery to enhance cytokine induction via toll-like receptor 9

We developed a potential cytosine–phosphate–guanosine oligodeoxynucleotide (CpG ODN) delivery system based on magnetic mesoporous silica (MMS) nanoparticles by binding of CpG ODN onto aminated MMS (MMS–NH2) nanoparticles to form CpG/MMS–NH2 complexes for toll-like receptor 9 (TLR9)-mediated induction of cytokines. Magnetization, serum stability, in vitro cytotoxicity, cellular uptake, and interleukin-6 (IL-6) induction of CpG/MMS–NH2 complexes were evaluated. The results showed that MMS nanoparticles exhibited superparamagnetic behavior with a saturation magnetization of 6.5 emu g−1. Also, MMS–NH2 nanoparticles had no cytotoxicity to Raw 264.7 cells, and CpG/MMS–NH2 complexes enhanced the serum stability of CpG ODN and could be localized in the endolysosomes after endocytosis by cells. Importantly, CpG/MMS–NH2 complexes significantly enhanced the TLR9-mediated IL-6 induction compared to free CpG ODN. Therefore, CpG/MMS–NH2 complexes could exhibit magnetic targeted delivery and significantly enhance the TLR9-mediated cytokine induction for stimulating immune responses.