In order to architecturally and functionally mimic native Extracellular Matrix （ECM）, a novel micro/nano-fibrous scaffold of hydroxyapetite/poly（lactide-co-glycolide） （HA/PLGA） composite was successfully prepared by melt-spinning method. A porous three-dimensional scaffold fabricated by melt-molding particulate-leaching method was used as control. This kind of scaffold comprising both nanofiber and microfiber had an original structure including a nano-network favorable for cell adhe- sion, and a micro-fiber providing a strong skeleton for support. The microfibers and nanofibers were blended homogeneously in scaffold and the compression strength reached to 6.27 MPa, which was close to human trabecular bone. The typical mi- cro/nano-fibrous structure was more benefcial for the proliferation and differentiation of Bone Mesenehymal Stem Cells （BMSCs）. The calcium deposition and Alkaline Phosphatase （ALP） activity were evaluated by the differentiation of BMSCs, and the results indicated that the temporary ECM was very beneficial for the differentiation of BMSCs into maturing osteoblasts. For repairing rabbit radius defects in vivo, micro/nano-fibrous scaffold was used for the purpose of rapid bone remodeling in the defect area. The results showed that a distinct bony callus of bridging was observed at 12 weeks post-surgery and the expression of osteogenesis-related genes （bone-morphogenetic protein-2, Osteonectin, collagen-I） increased because of the ECM-like structure. Based on the results, the novel micro/nano-fibrous scaffold might be a promising candidate for bone tissue engi- neering.
Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.
Shunjie LiuYusheng QinHongchen GuoXianhong WangFosong Wang
Herein, cisplatin-loaded poly（L-glutamic acid）-g-methoxy poly（ethylene glycol） nanoparticles were evaluated as a potential chemotherapeutic agent against osteosarcoma by using alone or with an i RGD（internalizing RGD, CRGDKDPDC）. The release rate of platinum from the cisplatin-loaded nanoparticles CDDP/PLG160-g-m PEG2K（CDDP-NPs） accelerated with the increase of the acidity of the environment. In vitro test demonstrated that CDDP-NPs could inhibit the proliferation of MNNG/Hos osteosarcoma cells with IC50（72 h） of 12.2 μg·mL^-1. In vivo test for MNNG/Hos osteosarcoma tumor bearing mice exhibited that CDDP-NPs had comparable or slightly higher efficacy but significantly lower side effects in comparison with free CDDP. The coadministration of i RGD could further enhance the anticancer efficacy of CDDP-NPs against MNNG/Hos osteosarcoma without bringing obvious side effects. Therefore, CDDP-NPs using alone or with iRGD have great potential for the treatment of osteosarcoma.
β-Imidophosphonamido ligated lutetium alkyl complex（NPNDipp）Lu（CH2Si Me3）2（THF）（NPNDipp = Ph2P（NC6H3iPr2-2,6）2） with the activation of AliBu3 and [Ph3C][B（C6F5）4] exhibited high catalytic activity, medium syndio-（rr = 66%） but remarkably high 3,4-regioselectivity for the polymerization of β-myrcene（MY）. In sharp contrast, high isotactic 3,4-polymyrcene（PMY）（mm = 95%） was obtained by the precursor（NPN^Et）Lu（CH2Si Me3）2（THF）（NPN^Et = PPh2（NC6H3^iPr2-2,6）（NC6H4-Et-2）） with less bulky substituents on the N-aryl ring.
