Co-reporter:Junquan Meng, Huichuan Yang, Man Cao, Lei Li, Qing Cai
Materials Science and Engineering: C 2017 Volume 78(Volume 78) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.msec.2017.04.008
•Curing kinetics of photocurable composite resins were studied in relating to photoinitiator content.•Elution behaviors of composite resins were determined in relating to their curing kinetic.•Cytotoxicity of composite resins was evaluated in relating to their elution behaviors.Cytotoxicity of photocurable composite resins is a key issue for their safe use in dental restoration. Curing kinetic and elution behaviors of the composite resin would have decisive effects on its cytotoxicity. In this study, composite resins composed of bisphenol-glycidyl dimethacrylate (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), camphorquinone (CQ), N,N-dimethylaminoethyl methacrylate (DMAEMA) and barium glass powders were prepared by setting the photoinitiators CQ/DMAEMA at 0.5 wt%, 1 wt% or 3 wt% of the total weight of Bis-GMA/TEGDMA. The ratio of Bis-GMA/TEGDMA was 6:4, the ratio of CQ/DMAEMA was 1:1, and the incorporated inorganic powder was 75 wt%. Then, curing kinetics were studied by using real-time Fourier transform infrared spectroscopy (FTIR) and photo-DSC (differential scanning calorimeter). Elution behaviors in both ethanol solution and deionized water were monitored by using liquid chromatogram/mass spectrometry (LC/MS). Cytotoxicity was evaluated by in vitro culture of L929 fibroblasts. Finally, they were all analyzed and correlated in terms of initiator contents. It was found that the commonly used 0.5 wt% of photoinitiators was somewhat insufficient in obtaining composite resin with low cytotoxicity.
•Porous fibers were prepared via electrospinning and calcination using silica nanospheres as building blocks.•The porous structure was derived from the inherent spaces between carbon-bound nanospheres.•Porosity could be regulated by controlling the content of the sacrificial polymer polymethylmethacrylate (PMMA).•The fibers demonstrated drug absorption and release capabilities in relating to their pore volumes.Porous silica fibers were fabricated aiming to broaden the applications of SiO2 nanosphere materials. The fibers were built with SiO2 nanospheres via electrospinning and calcinations. At first, SiO2 nanospheres (synthesized by Stober method) were surface-modified using γ-aminopropyltriethoxysilane to obtain SiO2-NH2 nanospheres, which dispersed homogeneously in the solvent. Then, polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) were introduced in different weight ratios into the suspension. Subsequently, PAN/PMMA/SiO2 composites were electrospun, followed by preoxidization and calcination to transfer PAN into carbon form and to remove PMMA component. Thus, porous silica fibers were fabricated with SiO2 nanospheres binding together during carbonization and porous structure was formed. The porosity, pore size and pore volume of porous silica fibers were controllable by adjusting the content of SiO2 nanospheres and the weight ratio of PAN/PMMA. Accordingly, the drug adsorption and release performance of these porous silica fibers depended on their micro-structural features. The thus-obtained porous silica fibers displayed great potentials in applications such as drug carriers and adsorbents.Download high-res image (158KB)Download full-size image
Co-reporter:Zhao-Hui Huang;Peng-Fei Wei;Le Jin;Xiao-Qing Hu;Xiao-Ping Yang
Journal of Materials Chemistry B 2017 vol. 5(Issue 47) pp:9300-9311
Publication Date(Web):2017/12/06
DOI:10.1039/C7TB02281F
Nanomedicines have found promising applications in regulating the biological behaviors of cells because of the cell endocytosis effect. To enhance the osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs), which is one of the key issues in relation to bone regeneration, a biodegradable simvastatin-bearing polyphosphazene prodrug was synthesized and made into nanoparticles (NPs). At the same time, photoluminescent tryptophan ethyl ester and hydrolyzable glycine ethyl ester were introduced as co-substituted side groups onto the polyphosphazene backbone. The resultant polymer, poly(simvastatin-co-ethyl tryptophanato-co-ethyl glycinato)phosphazene (PTGP-SIM), displayed the expected features of photoluminescence, degradability and sustained SIM release. Endocytosis of PTGP-SIM NPs by BMSCs and the location of internalized NPs, were visualized via the inherent photoluminescence features of PTGP-SIM. Thus, simvastatin was released inside the cells directly along with polymer degradation and could play a role in promoting osteogenic differentiation efficiently at quite a low local concentration. From the results, the present study suggested a very promising biomaterial for use as a flexible and functional carrier for bioactive components, which could find wide applications in relation to tissue regeneration.
Co-reporter:Zhao-Hui Huang;Peng-Fei Wei;Le Jin;Xiao-Qing Hu;Xiao-Ping Yang
Journal of Materials Chemistry B 2017 vol. 5(Issue 47) pp:9300-9311
Publication Date(Web):2017/12/06
DOI:10.1039/C7TB02281F
Nanomedicines have found promising applications in regulating the biological behaviors of cells because of the cell endocytosis effect. To enhance the osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs), which is one of the key issues in relation to bone regeneration, a biodegradable simvastatin-bearing polyphosphazene prodrug was synthesized and made into nanoparticles (NPs). At the same time, photoluminescent tryptophan ethyl ester and hydrolyzable glycine ethyl ester were introduced as co-substituted side groups onto the polyphosphazene backbone. The resultant polymer, poly(simvastatin-co-ethyl tryptophanato-co-ethyl glycinato)phosphazene (PTGP-SIM), displayed the expected features of photoluminescence, degradability and sustained SIM release. Endocytosis of PTGP-SIM NPs by BMSCs and the location of internalized NPs, were visualized via the inherent photoluminescence features of PTGP-SIM. Thus, simvastatin was released inside the cells directly along with polymer degradation and could play a role in promoting osteogenic differentiation efficiently at quite a low local concentration. From the results, the present study suggested a very promising biomaterial for use as a flexible and functional carrier for bioactive components, which could find wide applications in relation to tissue regeneration.
The effects of dopamine reduced graphene oxide (pDop-rGO) on the curing activity and mechanical properties of epoxy-based composites were evaluated. Taking advantage of self-polymerization of mussel-inspired dopamine, pDop-rGO was prepared through simultaneous functionalization and reduction of graphene oxide (GO) via polydopamine coating. Benefiting from the universal binding ability of polydopamine, good dispersion of pDop-rGO in epoxy matrix was able to be achieved as the content of pDop-rGO being below 0.2 wt %. Curing kinetics of epoxy composites with pDop-rGO were systematically studied by nonisothermal differential scanning calorimetry (DSC). Compared to the systems of neat epoxy or epoxy composites containing GO, epoxy composites loaded with pDop-rGO showed lower activation energy (Eα) over the range of cure (α). It revealed that the amino-bearing pDop-rGO was able to react with epoxy matrix and enhance the curing reactions as an amine-type curing agent. The nature of the interactions at GO-epoxy interface was further evaluated by Raman spectroscopy, confirming the occurrence of chemical bonding. The strengthened interfacial adhesion between pDop-rGO and epoxy matrix thus enhanced the effective stress transfer in the composites. Accordingly, the tensile and flexural properties of EP/pDop-rGO composites were enhanced due to both the well dispersion and strong interfacial bonding of pDop-rGO in epoxy matrix.Keywords: curing kinetics; dopamine; epoxy; graphene oxide; nonisothermal differential scanning
Co-reporter:Dan Cheng, Rongrong Xie, Le Jin, Man Cao, Xiaolong Jia, Qing Cai and Xiaoping Yang
RSC Advances 2016 vol. 6(Issue 59) pp:53958-53966
Publication Date(Web):19 May 2016
DOI:10.1039/C6RA03229J
Bioactive glass (BG)-containing carbon nanofibers (CNFs) were prepared by combining the processes of sol–gel, polyacrylonitrile (PAN) electrospinning and heat treatment. Two types of BG, i.e. 45S and 68S, were incorporated. The crystalline structure evolution of the BG component during the formation of the CNFs was characterized by XRD, SEM, and TEM observations in relation to silicon content. Then the apatite-forming ability of the hybridized CNF/BG in simulated body fluid was evaluated in relation to the crystalline structure of the BG component. Interactions between functional groups in PAN and BG sol–gel precursors were identified in the steps of electrospinning and heat treatment. As a result, the 45S-type BG containing less silicon formed α-CaSiO3, while the 68S-type BG containing more silicon transformed to β-CaSiO3 in the final hybridized CNF/BG upon carbonization. This difference led to different dissolution rates and osteocompatibility activities of the BG component from the hybrids, which regulated their capacities in inducing apatite deposition, proliferation and osteogenic differentiation of bone mesenchymal stromal cells.
Co-reporter:Dan Cheng, Rongrong Xie, Tianhong Tang, Xiaolong Jia, Qing Cai and Xiaoping Yang
RSC Advances 2016 vol. 6(Issue 5) pp:3870-3881
Publication Date(Web):21 Dec 2015
DOI:10.1039/C5RA23337B
The hybrids of bioactive glass-ceramic (BG) decorated carbon nanofibers (CNFs) have drawn wide interest as bone repairing materials. Herein, hybridized CNFs were produced from electrospinning the mixture solution of polyvinylpyrrolidone (PVP) and BG sol–gel precursors, followed by preoxidation and carbonization. Choosing 45S-type BG (mol%: 46.10% SiO2–41.48% CaO–12.42% P2O5) as the model, the interaction of BG precursors with PVP and the micro-structural evolution of CNF/BG composites were systematically evaluated in relation to aging times (1–7 days) of BG precursor solution. With aging time prolonging, BG precursors underwent morphological changes from small sol clusters with a loosely and randomly branched structure at 1 day, to a fully developed Si-network structure at 3 days, and finally to a dense Si-network at 7 days. On one hand, it showed continuous increase in network linking degree. On the other hand, the gel particles underwent the process of size increase and subsequently decrease. This directly influenced the miscibility between BG precursors and PVP in solution, and the surface morphology of CNF/BG composites. At short aging times, the sol–gel solution of BG precursors mixed uniformly with PVP and the resulting BG nanoparticles were less likely to migrate toward the fiber surface. With the aging time prolonging, the phase separation between BG precursors and PVP facilitated more BG nanoparticles to form on the fiber surface. Calcium ions were found to be able to interact with carbonyl groups in PVP, while phosphorus element would be lost gradually depending on aging time, which led the CaSiO3 formed in the final CNF/BG changing from a weak to strong crystal state along with longer aging time. By soaking in simulated body fluid, it was found that the CNF/BG composites prepared from BG precursor sol–gel solution with 7 day aging demonstrated the fastest apatite deposition, which was ascribed to those abundant BG nanoparticles on the fiber surface having exposed numerous nucleation sites for the apatite deposition. Promisingly, CNF/BG composites developed from electrospinning and carbonization of PVP/BG sol–gel mixtures were envisioned good choices for bone repairing.
Co-reporter:Dan Cheng, Zhiwei Ren, Lijuan Guo, Cuihua Zhang, Xiaolong Jia, Qing Cai and Xiaoping Yang
RSC Advances 2016 vol. 6(Issue 1) pp:428-438
Publication Date(Web):03 Dec 2015
DOI:10.1039/C5RA19740F
Composite carbon nanofibers (CNFs) containing bioglass (BG) nanoparticles displayed different morphology and microstructures depending on the sintering temperature (800, 1000 and 1200 °C) when they were produced from an electrospun polyacrylonitrile–BG precursor blend nanofibers. Biomineralization using simulated body fluid (SBF) and biological evaluation using an osteoblast culture were performed to investigate their relationship with sintering temperature. Characterization revealed that the BG nanoparticles on CNF/BG sintered at 1000 °C (CNF/BG-1000) possessed small particle size and uniform size distribution, and the crystallinity of the BG nanoparticles increased as the sintering temperature was increased from 800 to 1200 °C. The dissolution rate of the BG nanoparticles was thus different between the cases, which enhanced the biomineralization and cell proliferation/differentiation to varying degrees. Benefiting from the homogeneous distribution and large specific surface area of the BG nanoparticles on the CNFs, the results demonstrated that CNF/BG-1000 had the strongest ability in promoting apatite deposition, proliferation and osteogenic differentiation of MC3T3-E1 pre-osteoblasts in comparison with CNF/BG sintered at 800 or 1200 °C. The results demonstrate a flexible tool to regulate the physiochemical and biological properties of CNF/BG composites by controlling the sintering temperature, which could find promising applications in skeleton repairing.
Colloids and Surfaces B: Biointerfaces 2016 Volume 144() pp:238-249
Publication Date(Web):1 August 2016
DOI:10.1016/j.colsurfb.2016.04.025
•Different SiO2-PMMA nanospheres were prepared using Stober and ATRP methods.•SiO2-PMMA nanosphere composed nanofibers were directly fabricated by electrospinning.•One-dimensional necklace-like SiO2-PMMA nanofibers were successfully obtained.•The polymer-like characteristics of polymer-grafted inorganic particles was verified.The direct fabrication of hybrid nanofibres composed of poly(methyl methacrylate)-grafted SiO2 (SiO2-PMMA) nanospheres via electrospinning was investigated in detail. SiO2-PMMA nanospheres were successfully prepared, with the SiO2 nanospheres synthesized via the Stober method, followed by in situ surface-initiated atom transfer radical polymerization of methyl methacrylate (MMA). Electrospinning was carried out with N,N-dimethylformamide (DMF) as the solvent to disperse SiO2-PMMA nanospheres. The size of the SiO2 core, the molecular weight of the PMMA shell and the concentration of the SiO2-PMMA/DMF solution all had substantial effects on the morphology and structure of electrospun nanofibres composed of SiO2-PMMA nanospheres. When these determining factors were well-tailored, it was found that one-dimensional necklace-like nanofibres were obtained, with SiO2-PMMA nanospheres aligned one by one along the fibre. The successful fabrication of nanofibres by directly electrospinning the SiO2-PMMA/DMF solution verified that polymer-grafted particles possess polymer-like characteristics, which endowed them with the ability to be processed into desirable shapes and structures.Formation mechanism of electrospun SiO2-PMMA nanofibers under different conditions.
The importance of developing photoluminescent biodegradable scaffolding materials for tissue engineering is obvious, but it meets challenges with conventional biodegradable polymers such as aliphatic polyesters. In this study, photoluminescent biodegradable polyphosphazenes (PTA) were suggested as alternatives to target for long-term in vivo tracking applications. The PTA polymers were synthesized via nucleophilic cosubstitution of linear poly(dichlorophosphazene) with a fluorescent compound (TPCA) and alanine ethyl ester. The TPCA, with high fluorescent intensity and high quantum yield (∼0.5), was synthesized from citric acid and 2-aminoethanethiol. The resulted PTA polymers demonstrated adjustable degradation rates and fluorescent intensities in relating to their chemical compositions. In comparison with TPCA, the photostability of PTA polymers has been significantly improved, which made the long-term in vivo tracking feasible. PTA polymers were proven biocompatible and noncytotoxic for biomedical applications via both in vitro cell culture and in vivo implantation evaluations. During the 24-week subcutaneous implantation in mouse, the location and the degradation of PTA polymer were clearly visualized with the aid of fluorescent excitation and emission. In summary, PTA polymers were envisioned as good choices for tissue regeneration as scaffolding materials with in situ bioimaging potentials.
Co-reporter:Xiaoyan Wang, Qing Cai, Xuehui Zhang, Yan Wei, Mingming Xu, Xiaoping Yang, Qi Ma, Yali Cheng, Xuliang Deng
Materials Science and Engineering: C 2016 Volume 59() pp:464-470
Publication Date(Web):1 February 2016
DOI:10.1016/j.msec.2015.10.044
•Bis-GMA/TEGDMA resins containing nanoscale SiO2 fillers were prepared.•SiO2 nanofibers were efficient in improving the overall performance of resins.•Nanofibrous fillers displayed the ability of forming network structures in resins.The major objective of this study was to explore the effects of silicon dioxide (SiO2) nanofibers on the performance of 2, 2-bis-[4-(methacryloxypropoxy)-phenyl]-propane (Bis-GMA)/tri-(ethyleneglycol) dimethacrylate (TEGDMA) dental composites. At first, the mechanical properties of Bis-GMA/TEGDMA (50/50, w/w) resins containing different contents of SiO2 nanofibers were evaluated to identify the appropriate composition to achieve the significant reinforcing effect. Secondly, optimized contents (5 or 10 wt.%) of SiO2 nanofibers were mixed into resins together with SiO2 microparticles, which was 60 wt.% of the resin. Controls for comparison were Bis-GMA/TEGDMA resins containing only SiO2 microparticles (60 wt.%) or with additional SiO2 nanoparticles (5 or 10 wt.%). Properties including abrasion, polymerization shrinkage and mechanical properties were evaluated to determine the contribution of SiO2 nanofibers. In comparison with SiO2 nanoparticles, SiO2 nanofibers improved the overall performance of Bis-GMA/TEGDMA composite resins, especially in improving abrasion resistance and decreasing polymerization shrinkage. The explanations were that one-dimensional SiO2 nanofibers were able to shield particular fillers from being abraded off, and able to form a kind of overlapped fibrous network to resist polymerization shrinkage. With these approaches, SiO2 nanofiber-containing Bis-GMA composite resins were envisioned a promising choice to achieve long-term durable restorations in clinical therapies.
Materials Science and Engineering: C 2016 Volume 58() pp:742-749
Publication Date(Web):1 January 2016
DOI:10.1016/j.msec.2015.09.026
•Glass fibers were coated with poly(methylmethacrylate) (PMMA) or polydopamine (PDA).•Modified fibers displayed good interfacial adhesion with acrylate resin matrix.•PDA/PMMA co-coated fibers have the best interfacial adhesion with the resin.•A light-curable flexible prepreg was obtained for dental restoration.To obtain a kind of light-curable fiber-reinforced composite for dental restoration, an excellent interfacial adhesion between the fiber and the acrylate resin matrix is quite essential. Herein, surface modification on glass fibers were carried out by coating them with poly(methyl methacrylate) (PMMA), polydopamine (PDA), or both. The PMMA or PDA coating was performed by soaking fibers in PMMA/acetone solution or dopamine aqueous solution. PDA/PMMA co-coated glass fibers were obtained by further soaking PDA-coated fibers in PMMA/acetone solution. These modified fibers were impregnated with bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (5:5, w/w) dental resin at a volume fraction of 75%, using unmodified fibers as reference. Light-cured specimens were submitted to evaluations including flexural properties, morphological observation, dynamic mechanical thermal analysis (DMTA) and pull-out test. In comparison with unmodified glass fibers, all the modified glass fibers showed enhancements in flexural strength and modulus of Bis-GMA/TEGDMA resin composites. Results of DMTA and pull-out tests confirmed that surface modification had significantly improved the interfacial adhesion between the glass fiber and the resin matrix. Particularly, the PDA/PMMA co-coated glass fibers displayed the most efficient reinforcement and the strongest interfacial adhesion due to the synergetic effects of PDA and PMMA. It indicated that co-coating method was a promising approach in modifying the interfacial compatibility between inorganic glass fiber and organic resin matrix.
Co-reporter:Xukang Gao, Jinle Lan, Xiaolong Jia, Qing Cai, Xiaoping Yang
Materials Science and Engineering: C 2016 Volume 61() pp:174-179
Publication Date(Web):1 April 2016
DOI:10.1016/j.msec.2015.12.033
•Hybridized carbon nanofibers containing calcium phosphate nanoparticles (CNF/CaP) were prepared.•CNF/CaP displayed excellent interfacial adhesion with epoxy matrix.•The shortened CNF/CaP demonstrated effective reinforcement for epoxy composites.•The resulting epoxy/CaP composites were biocompatible.Hybridized carbon nanofibers containing calcium phosphate nanoparticles (CNF/CaP) were investigated as osteocompatible nanofillers for epoxy resin. The CNF/CaP was produced by electrospinning mixture solution of polyacrylonitrile and CaP precursor sol–gel, followed by preoxidation and carbonization. The continuous and long CNF/CaP was ultrasonically chopped, mixed into epoxy resin and thermo-cured. Compared to pure CNFs with similar ultrasonication treatment, the shortened CNF/CaP reinforced composites demonstrated significant enhancement in flexural properties of epoxy composites, benefiting from the improved interfacial adhesion between CNF/CaP and resin matrix. The resulting composites also displayed good biocompatibility and sustained calcium ion release, which categorized them as promising materials for bone repairing.
Co-reporter:Cuihua Zhang, Dan Cheng, Tianhong Tang, Xiaolong Jia, Qing Cai and Xiaoping Yang
Journal of Materials Chemistry A 2015 vol. 3(Issue 26) pp:5300-5309
Publication Date(Web):26 May 2015
DOI:10.1039/C5TB00921A
Bioactive glass (BG) decorated nanoporous composite carbon nanofibers (PCNF–BG) were prepared for the purpose of obtaining effective substrates for skeletal tissue regeneration. The preparation was conducted by electrospinning of polyacrylonitrile (PAN)–polymethylmethacrylate (PMMA) blends with the addition of sol–gel precursors of 58s-type (mol%: 58% SiO2–38% CaO–4% P2O5) BG, followed by high temperature thermal treatment. The removal of PMMA during the carbonization of PAN generated numerous slit-like nanoporous structures along CNFs, leading to a significant enhancement in the specific surface area, surface roughness and pore volume, which was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) characterizations. PCNF–BG composites with different specific surface areas were biologically evaluated by experiments of biomineralization in simulated body fluid (SBF), in vitro MC3T3-E1 osteoblast proliferation and osteogenic differentiation. Compared to non-porous CNF/BG, the nanoporous structure distinctively enlarged the interfacial reaction area of the BG component with a medium environment and thus enhanced the bioactivity of CNFs by accelerating the dissolution of the BG component and providing abundant nucleation sites for hydroxyapatite depositions. The released ions displayed distinct promotion in proliferation and osteogenic differentiation of osteoblast cells, which promoted the osteocompatibility of carbon-based materials significantly.
Co-reporter:Pei Zhao, Dawei Li, Fei Yang, Yuanzheng Ma, Tiantian Wang, Shun Duan, Hong Shen, Qing Cai, Decheng Wu, Xiaoping Yang and Shenguo Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 34) pp:6885-6896
Publication Date(Web):22 Jul 2015
DOI:10.1039/C5TB00946D
To cure serious bone tuberculosis, a novel long-term drug delivery system was designed and prepared to satisfy the needs of both bone regeneration and antituberculous drug therapy. An antituberculous drug (rifampicin, RFP) was loaded into a porous scaffold, which composed of a newly designed polylactone, poly(ε-caprolactone)-block-poly(lactic-co-glycolic acid) (b-PLGC) copolymer, and β-tricalcium phosphate (β-TCP). The releasing results demonstrated that RFP could be steadily released for as long as 12 weeks both in vitro and in vivo. During the in vivo experimental period, the drug concentration in tissues surrounding implants was much higher than that in blood which was still superior to the effective value to kill mycobacterium tuberculosis. MC3T3-E1 osteoblasts proliferated well in extracts and co-cultures on composite scaffolds, indicating good cytocompatibility and cell affinity of the scaffolds. The results of a rabbit radius repair experiment displayed that scaffolds have good bone regeneration capacity. The RFP-loaded b-PLGC/TCP composite scaffold thus could be envisioned to be a potential and promising substrate in clinical treatment of bone tuberculosis.
Alignment states of one-dimensional multiwalled carbon nanotubes containing various contents of zero-dimensional ferriferrous oxide nanoparticles (MWCNT–Fe3O4) were numerically characterized. MWCNT–Fe3O4 complexes were successfully prepared via in situ surface-initiated atom transfer radical polymerization, followed by a coprecipitation process. The complexes showed strong magnetism, which endowed them with the ability to be aligned under the action of an external magnetic field. The intensity of the magnetic field, loading content of Fe3O4 nanoparticles, and viscosity of dispersing medium, however, all had substantial effects on the alignment degree. To evaluate the alignment effectively and quantitatively, an orientation tensor description based on marking the direction of a single MWCNT in a selected region of optical images was employed. The results showed that MWCNT–Fe3O4 complex containing 26 wt % of Fe3O4 nanoparticles achieved a desirable alignment in deionized water under a magnetic field intensity of 0.10 T. Accordingly, epoxy composites reinforced with such aligned MWCNT–Fe3O4 complexes displayed 12.3 and 10.9% enhancement in tensile strength and modulus, as well as 8.9 and 6.1% enhancement in flexural strength and modulus, respectively.Keywords: alignment; Fe3O4 nanoparticle; multiwalled carbon nanotube; numerical characterization; orientation tensor
In this study, thermosensitive poly(N-isopropylacrylamide) (PNIPAAm) was grafted onto gelatin via atom transfer radical polymerization (ATRP). The chemical structure of PNIPAAm-grafted gelatin (Gel–PNIPAAm) was confirmed by XPS, ATR-IR, and 1H NMR characterizations. Gel–PNIPAAm aqueous solution exhibited sol-to-gel transformation at physiological temperature, and was studied as injectable hydrogel for bone defect regeneration in a cranial model. The hydrogel was biocompatible and demonstrated the ability to enhance bone regeneration in comparison with the untreated group (control). With the incorporation of rat bone mesenchymal stem cells (BMSCs) into the hydrogel, the bone regeneration rate was further significantly enhanced. As indicated by micro-CT, histological (H&E and Masson) and immunohistochemical (osteocalcin and osteopontin) staining, newly formed woven bone tissue was clearly detected at 12 weeks postimplantation in the hydrogel/BMSCs treated group, showing indistinguishable boundary with surrounding host bone tissues. The results suggested that the thermosensitive Gel–PNIPAAm hydrogel was an excellent injectable delivery vehicle of BMSCs for in vivo bone defect regeneration.Keywords: bone defect; bone mesenchymal stem cells; hydrogel; injectable; thermosensitive;
The poor interfacial adhesion between organic and inorganic components remains the primary obstacle in obtaining composite scaffolds of high performance for bone tissue engineering. Mussel-inspired dopamine surface modification on inorganic components is a potential solution for this problem. Herein, hydroxyapatite (HA) nano-rods were freshly made by a co-precipitation method and subjected to polydopamine (PDA) coating. Then the modified HA nano-rods were mixed into biodegradable poly(L-lactide) (PLLA) to get PLLA/HA nanocomposites. The PDA modification was found to be mild and easy to handle, and was effective in improving the dispersibility of HA nano-rods in chloroform and especially in PLLA/chloroform solution. The resulting PLLA/HA composite films and porous scaffolds demonstrated significant enhancements in their mechanical properties at relatively high contents (30–60 wt%) of modified HA nano-rods in comparison with those composites containing unmodified HA nano-rods. This was thought to be mainly attributed to both the even distribution of modified HA nano-rods throughout the PLLA matrix and the strong interfacial adhesion between HA and PLLA components. The PLLA/HA composites displayed good biocompatibility with bone mesenchymal stem cells (BMSCs) and could enhance the osteogenic differentiation of BMSCs, indicating the PDA modification has no adverse effect on biological properties. These results confirmed the idea of using mussel-inspired dopamine surface modification as a feasible and efficient approach in developing organic–inorganic composite materials for bone regeneration studies.
Co-reporter:Xiaolong Jia, Junyi Zheng, Song Lin, Wenbin Li, Qing Cai, Gang Sui and Xiaoping Yang
RSC Advances 2015 vol. 5(Issue 56) pp:44853-44864
Publication Date(Web):13 May 2015
DOI:10.1039/C5RA06397C
The effects of butyl glycidyl ether (BGE) activated montmorillonites (BGE-MMTs) on moisture-resistant characteristics of epoxy-based composites were evaluated. The activated MMTs were prepared by intercalating BGE into the inter-layer surfaces of octadecyl ammonium modified MMTs (O-MMTs) under ultrasonication, and in the form of liquid nano-reinforcement. It showed advantages of low viscosity, excellent dispersibility and high chemical reactivity in the epoxy matrix. The enhancements in tensile and flexural properties of BGE-MMTs/epoxy composites confirmed the well dispersion of BGE-MMTs in epoxy matrix and the strong interfacial adhesion between the two components. More importantly, the well-dispersed BGE-MMTs in epoxy matrix led to significant enhancement in the moisture-barrier properties of epoxy composites. In comparison with that of neat epoxy, the moisture diffusion coefficient of BGE-MMTs/epoxy composites significantly decreased from 10.1 × 10−6 to 0.3 × 10−6 cm2 s−1. The enhancement in moisture-barrier properties was ascribed to the exfoliated two-dimensional lamellar structure of MMTs extending the effective penetration paths of water molecules into tortuous forms. A model concerning moisture diffusion in BGE-MMTs/epoxy composites was suggested.
Co-reporter:Xiaolong Jia, Tianhong Tang, Dan Cheng, Cuihua Zhang, Ran Zhang, Qing Cai, Xiaoping Yang
Colloids and Surfaces B: Biointerfaces 2015 Volume 136() pp:585-593
Publication Date(Web):1 December 2015
DOI:10.1016/j.colsurfb.2015.09.062
•CNF/BG composites were prepared through electrospinning, preoxidation and carbonization.•Micro-structural evolution of CNF/BG composites were evaluated with aging times.•At short aging time, weakly crystallized BG nanoparticles could induce fast apatite formation.•Aging time was a useful tool to control biological features of CNF/BG composites.Bioactive glass (BG)—containing carbon nanofibers (CNFs) are promising orthopaedic biomaterials. Herein, CNF composites were produced from electrospinning of polyacrylonitrile (PAN)/BG sol–gel precursor solution, followed by carbonization. Choosing 58S-type BG (mol%: 58.0% SiO2-26.3% CaO-15.7% P2O5) as the model, micro-structural evolution of CNF/BG composites was systematically evaluated in relating to aging times of BG precursor solution. With aging time prolonging, BG precursors underwent morphological changes from small sol clusters with loosely and randomly branched structure to highly crosslinked Si-network structure, showing continuous increase in solution viscosity. BG precursor solution with low viscosity could mix well with PAN solution, resulting in CNF composite with homogeneously distributed BG component. Whereas, BG precursor gel with densely crosslinked Si-network structure led to uneven distribution of BG component along final CNFs due to its significant phase separation from PAN component. Meanwhile, BG nanoparticles in CNFs demonstrated micro-structural evolution that they transited from weak to strong crystal state along with longer aging time. Biomineralization in simulated body fluid and in vitro osteoblasts proliferation were then applied to determine the bioactivity of CNF/BG composites. CNF/BG composites prepared from shorter aging time could induce both faster apatite deposition and cell proliferation rate. It was suggested weakly crystallized BG nanoparticles along CNFs dissolved fast and was able to provide numerous nucleation sites for apatite deposition, which also favored the proliferation of osteoblasts cells. Aging time could thus be a useful tool to regulate the biological features of CNF/BG composites.Polyacrylonitrile electrospinning in combination with sol–gel method was applied to produce 58S bioactive glass (mol%: 58.0% SiO2-26.3% CaO-15.7% P2O5) containing carbon nanofibers (CNF/BG). The micro-structural evolution of BG in CNF composites and its effect on biomineralization behavior were systematically evaluated in relating to aging times of BG precursor sol–gel solution.
Polyacrylonitrile (PAN) electrospinning in combination with sol–gel method has been a common technique to produce inorganic nanoparticles containing composite carbon nanofibers (CNFs) for diverse applications. To investigate the morphology evolution and crystal transformation of inorganic components along with CNF formation, bioactive glass (BG) containing CNFs (CNF/BG) were prepared by sintering as-spun PAN/precursor composite nanofibers in a nitrogen atmosphere at temperatures of 800, 1000 and 1200 °C. Comprehensive characterizations were performed with TEM, SEM-EDXA and XRD. For samples sintered at 800 °C, numerous BG nanoparticles were observed inside the CNFs and mainly in an amorphous state. With the sintering temperature raised to 1000 °C, a number of spherical BG nanoparticles were detected on the surface of the resulting CNFs, with a crystal structure of wollastonite (β-CaSiO3) polycrystals. When the samples were sintered at 1200 °C, the BG nanoparticles on the surface of CNFs merged into forms with cuboid-like geometry, mainly consisting of pseudowollastonite (Ca3(Si3O9)) single crystals. Based on the geometry evolution and dynamic size distribution function analyses (Ostwald ripening and Smoluchowski equations), it was concluded that the growth of BG nanoparticles conformed to the ripening mechanism at 800 °C and migration–coalescence mechanism at 1200 °C, while the process involved both ripening and migration–coalescence mechanisms at 1000 °C.
Materials Science and Engineering: C 2014 Volume 43() pp:432-438
Publication Date(Web):1 October 2014
DOI:10.1016/j.msec.2014.07.050
•Iodine-containing cyclotriphosphazenes were prepared via nucleophilic substitution.•The cyclotriphosphazenes endowed Bis-GMA/TEGDMA resins radiopacity.•The cyclotriphosphazenes caused a minor adverse effect on mechanical properties.In this study, a strategy of using iodine-containing cyclophosphazenes as radiopacifiers for dental composite resin was evaluated. It was hypothesized that cyclophosphazenes bearing both iodine and acrylate group swere able to endow composite resins radiopacity without compromising mechanical properties. The cyclophosphazene compounds were synthesized by subsequently nucleophilic substitution of hexachlorocyclotriphosphazene with hydroxyethyl methacrylate (HEMA) and 4-iodoaniline. Cyclotriphosphazenes containing two different molar ratios of HEMA to 4-iodoaniline (1:5 and 2:4) were obtained, and were identified with 1H NMR, FT-IR, UV and mass spectroscopy. The iodine-containing cyclophosphazenes were able to dissolve well in bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin, and were added at two contents (10 or 15%wt. of the resin). The resins were photo-cured and post-thermal treated before characterizations. The resulting composite resins demonstrated the ability of blocking X-ray. And the addition of HEMA-co-iodoaniline substituted cyclotriphosphazenes caused minor adverse effect on the mechanical properties of the resins because the cyclotriphosphazenes could mix well and react with the resins. The presence of rigid phosphazene rings between resin backbones displayed an effective function of decreasing polymerization shrinkage. In summary, soluble and reactive iodine-containing cyclotriphosphazenes demonstrated advantages over traditional heavy metals or metal oxides in being used as additives for producing radiopaque dental resins.
Co-reporter:Liyuan Cheng, Xuegang Zhou, Hong Zhong, Xuliang Deng, Qing Cai, Xiaoping Yang
Materials Science and Engineering: C 2014 Volume 34() pp:262-269
Publication Date(Web):1 January 2014
DOI:10.1016/j.msec.2013.09.020
•NaF-loaded PAN–PMMA core–shell nanofibers were prepared by coaxial electrospinning.•The core–shell nanofibers were good reinforcements for Bis-GMA/TEGDMA restorative resin.•Sustained fluoride-ion release behaviors with minor initial burst release were obtained.A kind of core–shell nanofibers containing sodium fluoride (NaF) was produced and used as reinforcing materials for dimethacrylate-based dental restorative resins in this study. The core–shell nanofibers were prepared by coaxial-electrospinning with polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) solutions as core and shell fluids, respectively. The produced PAN–PMMA nanofibers varied in fiber diameter and the thickness of PMMA shell depending on electrospinning parameters. NaF-loaded nanofibers were obtained by incorporating NaF nanocrystals into the core fluid at two loadings (0.8 or 1.0 wt.%). Embedment of NaF nanocrystals into the PAN core did not damage the core–shell structure. The addition of PAN–PMMA nanofibers into Bis-GMA/TEGDMA clearly showed the reinforcement due to the good interfacial adhesion between fibers and resin. The flexural strength (Fs) and flexural modulus (Ey) of the composites decreased slightly as the thickness of PMMA shell increasing. Sustained fluoride releases with minor initial burst release were achieved from NaF-loaded core–shell nanofibers and the corresponding composites, which was quite different from the case of embedding NaF nanocrystals into the dental resin directly. The study demonstrated that NaF-loaded PAN–PMMA core–shell nanofibers were not only able to improve the mechanical properties of restorative resin, but also able to provide sustained fluoride release to help in preventing secondary caries.
Colloids and Surfaces B: Biointerfaces 2014 Volume 123() pp:753-761
Publication Date(Web):1 November 2014
DOI:10.1016/j.colsurfb.2014.10.026
•Polymer-coated CNTs with different surface functional groups were prepared.•Biomineralization of modified CNTs was performed using SBF.•Surface functional groups play important roles in nucleation, growth and morphology of apatite.•Positive acylamino group was helpful to obtain c-axis preferentially oriented CDHA from SBF.Substrate-controlled mineralization from simulated body fluid (SBF) has been studied as a model for biomineralization and for the synthesis of bioinspired hybrid materials. The mineralization procedure is complex and the features of final minerals are affected by many factors. Surface functional groups are among them and play important roles in inducing nucleation, crystal growth and transformation. In this study, multi-walled carbon nanotubes (MWCNTs) were surface-modified with poly(acrylic acid), polyacrylamide or poly(hydroxyethyl methylacrylate), and used as templates for biomineralization. The polymer coating was gained via photo-initiated polymerization of monomers and adsorption of polymer chains onto MWCNTs in solution. Then, the modified MWCNTs with different surface functional groups were incubated in 1.5 times SBF for different times to compare the effect of carboxyl, acylamino and hydroxyl group on calcium phosphate formation. The study involved various characterizations such as morphology observation, weight increase, chemical and crystal structures of deposited minerals at different soaking time points. In all cases, carbonated calcium-deficient hydroxyapatite (CDHA) was identified after 7 days immersion. The continuously growing mineral crystals would wrap MWCNTs into spherical composite particles ultimately. However, the rates of nucleation and crystal growth depended on the type of surface functional groups, in an order of COOH > CONH2 > OH. And their different charge characteristics led to different Ca/P ratios in initially formed minerals. It revealed that acylamino group, which demonstrated the lowest Ca/P ratio in nucleation stage, was helpful to obtain c-axis preferentially oriented morphology resembling the HA structure in natural bone tissue.
Co-reporter:Q. Yang, G. Sui, Y.Z. Shi, S. Duan, J.Q. Bao, Q. Cai, X.P. Yang
Carbon 2013 Volume 56() pp:288-295
Publication Date(Web):May 2013
DOI:10.1016/j.carbon.2013.01.014
A kind of composite carbon nanofibers (CNF) containing bioactive glass (BG) nanoparticles was produced for bone regeneration by a combination of electrospinning and sol–gel techniques. To produce the BG, compounds such as calcium nitrate, triethyl phosphate and tetraethyl orthosilicate were used as precursors and hydrolyzed to form a sol–gel solution, which was then added to a polyacrylonitrile (PAN) solution in N,N-dimethylformamide. The resulting mixture was electrospun to form PAN nanofibers containing the BG precursors. Upon oxidation and carbonization, the PAN nanofibers and BG precursors transformed into continuous CNF embedded with BG nanoparticles (CNF/BG). Through this fabrication technique, several CNF/BG composites were obtained by controlling the feeding ratios of the different precursors giving rise to BG nanoparticles with various compositions (i.e. containing 70–90 mol% of SiO2 component). In vitro biomineralization in a simulated body fluid and co-culture with MC3T3-E1 osteoblasts studies were performed to evaluate the osteocompatibility of the CNF/BG nanoparticle composites. When compared to pure CNF, the CNF/BG composites showed an improved ability to promote the in vitro formation of apatite and MC3T3-E1 proliferation, which was found to be dependent upon the composition of BG nanoparticles.
A kind of bioadhesive, dopamine, was first reported as the surface modifier of fiber posts.
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The polydopamine-coated fiber posts were tested having strong interfacial adhesion with composite resins using pull-out test.
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The results suggested the feasibility to prevent failure in endodontically treated teeth due to dislodgement of fiber post by using dopamine surface modification.
Co-reporter:Dingying Shan, Yuzhou Shi, Shun Duan, Yan Wei, Qing Cai, Xiaoping Yang
Materials Science and Engineering: C 2013 Volume 33(Issue 6) pp:3498-3505
Publication Date(Web):1 August 2013
DOI:10.1016/j.msec.2013.04.040
•Polylactide coated Fe3O4 nanoparticles were synthesized by co-precipitation.•The co-precipitated Fe3O4 nanoparticles dispersed well in polylactide nanofibers.•Magnetic polylactide/Fe3O4 nanofibers are good substrates for osteoblasts.Magnetic poly(l-lactide) (PLLA)/Fe3O4 composite nanofibers were prepared with the purpose to develop a substrate for bone regeneration. To increase the dispersibility of Fe3O4 nanoparticles (NPs) in the PLLA matrix, a modified chemical co-precipitation method was applied to synthesize Fe3O4 NPs in the presence of PLLA. Trifluoroethanol (TFE) was used as the co-solvent for all the reagents, including Fe(II) and Fe(III) salts, sodium hydroxide, and PLLA. The co-precipitated Fe3O4 NPs were surface-coated with PLLA and demonstrated good dispersibility in a PLLA/TFE solution. The composite nanofiber electrospun from the solution displayed a homogeneous distribution of Fe3O4 NPs along the fibers using various contents of Fe3O4 NPs. X-ray diffractometer (XRD) and vibration sample magnetization (VSM) analysis confirmed that the co-precipitation process had minor adverse effects on the crystal structure and saturation magnetization (Ms) of Fe3O4 NPs. The resulting PLLA/Fe3O4 composite nanofibers showed paramagnetic properties with Ms directly related to the Fe3O4 NP concentration. The cytotoxicity of the magnetic composite nanofibers was determined using in vitro culture of osteoblasts (MC3T3-E1) in extracts and co-culture on nanofibrous matrixes. The PLLA/Fe3O4 composite nanofibers did not show significant cytotoxicity in comparison with pure PLLA nanofibers. On the contrary, they demonstrated enhanced effects on cell attachment and proliferation with Fe3O4 NP incorporation. The results suggested that this modified chemical co-precipitation method might be a universal way to produce magnetic biodegradable polyester substrates containing well-dispersed Fe3O4 NPs. This new strategy opens an opportunity to fabricate various kinds of magnetic polymeric substrates for bone tissue regeneration.
It is important to improve the compatibility of hydroxyapatite (HA) nanoparticles in biodegradable polyesters to obtain desirable nanocomposites for bone tissue engineering applications. Polymer grafting has been proven an efficient way to get nanohybrids with good dispersibility in polymeric matrixes. In this paper, a new strategy to prepare HA–poly(l-lactide) (PLLA) nanohybrids was developed, where PLLA oligomers were grafted from HA nanoparticle surfaces via surface-initiated atom transfer radical polymerization (ATRP) of methylacrylate group terminated PLLA macromonomers (PLLA-MA). HA with the derived ATRP initiators was obtained by (1) preparation of HA from precursors in the presence of 3-aminopropyl-triethoxysilane (APTS) to produce the HA surface with terminal NH2 groups (HA–NH2) and (2) reaction of the NH2 groups of the HA–NH2 nanoparticles with 2-bromoisobutyryl bromide (BIBB) to produce the 2-bromoisobutyryl-immobilized nanoparticles (HA–Br). The obtained HA–PLLA nanohybrids demonstrated good dispersibility in chloroform. With the good dispersion of HA–PLLA nanohybrids in PLLA matrix, the resultant PLLA/HA–PLLA nanocomposites could much faster induce bone-like apatite-formation in simulated body fluids (SBF) than the PLLA/HA counterparts where the HA nanoparticles aggregated heavily. With the versatility of ATRP, properly, grafting oligomeric PLLA chains from HA nanoparticle surfaces is an effective means for the design of novel HA–polymer biohybrids for future bone tissue engineering applications.
Co-reporter:Jifu Mao, Shun Duan, Anna Song, Qing Cai, Xuliang Deng, Xiaoping Yang
Materials Science and Engineering: C 2012 Volume 32(Issue 6) pp:1407-1414
Publication Date(Web):1 August 2012
DOI:10.1016/j.msec.2012.04.018
Poly(lactide-co-glycolide) (PLGA) copolymers are the most prevalent materials for tissue engineering applications. To mimic the real microenvironment of extracellular matrix (ECM) for cell growth, nanofibrous PLGA scaffolds are preferred. PLGA5050 (in which the molar ratio of lactidyl to glycolidyl units is 50:50), which is an utterly amorphous polymer, was first reported to be made into nanofibrous networks (fiber diameter around 500 nm) using phase separation from PLGA5050/THF solutions in this study. The concentration of polymeric solution had significant effects on fiber diameter and unit length. Nonsolvent (e.g. H2O) was unnecessary to form the PLGA5050 gel, which was critical to nanofibrosis, as if the environmental temperature for gelation occurrence was low enough (− 70 °C). The physical crosslinks to stabilize the PLGA5050/THF gel were believed to be GA segments along the backbone owing to their inferior solubility in THF. The addition of H2O would cause adverse effects of liquid–liquid phase separation and nanofibrosis failure owing to the hydrophilicity of glycolidyl units. Associating with the phase separation method, particle-leaching technique was applied to fabricate three-dimensional scaffolds with macroporous and nanofibrous structures. To ensure the occurrence of nanofibrosis on macropore walls, the temperature of salt particles should be best lowed to − 70 °C beforehand. Accordingly, scaffolds prepared under varied parameters exhibited different nanofiber and pore morphologies, which affected the pore size, porosity, specific surface area, water contact angle and protein adsorption ability etc. The preliminary cell (MC3T3-E1) culture confirmed the cell ingrowth into the macroporous and nanofibrous PLGA5050 scaffolds in comparison with the solely nanofibrous matrixes. This kind of bi-scaled three dimensional matrixes can be superior candidate scaffolds for tissue engineering applications.Highlights► PLGA5050 was firstly made into nanofibrous networks via phase separation. ► Combining with particle-leaching, macroporous and nanofibrous scaffolds were gained. ► Cell culture confirmed the scaffolds being ideal candidates for tissue engineering.
ObjectiveThe object is to find a functional one-dimensional nanofibrous filler for composite resin, which is able to provide both efficient reinforcement and high antibacterial activity.MethodsHydroxyapatite (HA) nanowires were synthesized via hydrothermal technique using calcium oleate as the precursor. Polydopamine (PDA)–coated HA (HA–PDA) nanowires were prepared by soaking HA nanowires in dopamine (DA) aqueous solution. Silver nanoparticles (AgNPs)–laden HA (HA–PDA–Ag) nanowires were prepared via reduction reaction by adding silver nitrate and glucose into HA–PDA suspensions in DI water. The resulted HA–PDA–Ag nanowires were then mixed into Bis-GMA/TEGDMA (50/50, w/w) at 4–10 wt.%, thermal-cured, and submitted to characterizations including mechanical properties, interfacial adhesion between filler and resin matrix, distribution of HA nanowires and AgNPs, as well as silver ion release, cytotoxicity and antibacterial activity.ResultsHA–PDA–Ag nanowires were readily obtained and the loading amounts of AgNPs could be controlled by adjusting the feeding doses of silver nitrate and HA–PDA nanowires. Benefiting from the PDA surface layer, HA–PDA–Ag nanowires could disperse well in composite resin and form good interfacial adhesion with the resin matrix. In comparison with neat resin, significant increases in flexural strength and modulus of cured composites were achieved at the addition amounts of HA–PDA–Ag nanowires being 6–8 wt.%. The distribution of AgNPs was homogeneous throughout the resin matrix in all designs, which endowed the composites with high antibacterial activity against streptococcus mutans. Continuous silver ion release from composites was detected, however, it was determined the composites would have insignificant cytotoxicity based on the proliferation of L929 fibroblasts in extracts of HA–PDA–Ag nanowires.SignificanceThe finding proved that HA–PDA–Ag nanowires could serve as functional nanofillers for composite resins, which should help much in developing materials for satisfactory long-term clinical restorations.
Co-reporter:Cuihua Zhang, Dan Cheng, Tianhong Tang, Xiaolong Jia, Qing Cai and Xiaoping Yang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 26) pp:NaN5309-5309
Publication Date(Web):2015/05/26
DOI:10.1039/C5TB00921A
Bioactive glass (BG) decorated nanoporous composite carbon nanofibers (PCNF–BG) were prepared for the purpose of obtaining effective substrates for skeletal tissue regeneration. The preparation was conducted by electrospinning of polyacrylonitrile (PAN)–polymethylmethacrylate (PMMA) blends with the addition of sol–gel precursors of 58s-type (mol%: 58% SiO2–38% CaO–4% P2O5) BG, followed by high temperature thermal treatment. The removal of PMMA during the carbonization of PAN generated numerous slit-like nanoporous structures along CNFs, leading to a significant enhancement in the specific surface area, surface roughness and pore volume, which was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) characterizations. PCNF–BG composites with different specific surface areas were biologically evaluated by experiments of biomineralization in simulated body fluid (SBF), in vitro MC3T3-E1 osteoblast proliferation and osteogenic differentiation. Compared to non-porous CNF/BG, the nanoporous structure distinctively enlarged the interfacial reaction area of the BG component with a medium environment and thus enhanced the bioactivity of CNFs by accelerating the dissolution of the BG component and providing abundant nucleation sites for hydroxyapatite depositions. The released ions displayed distinct promotion in proliferation and osteogenic differentiation of osteoblast cells, which promoted the osteocompatibility of carbon-based materials significantly.
Co-reporter:Pei Zhao, Dawei Li, Fei Yang, Yuanzheng Ma, Tiantian Wang, Shun Duan, Hong Shen, Qing Cai, Decheng Wu, Xiaoping Yang and Shenguo Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 34) pp:NaN6896-6896
Publication Date(Web):2015/07/22
DOI:10.1039/C5TB00946D
To cure serious bone tuberculosis, a novel long-term drug delivery system was designed and prepared to satisfy the needs of both bone regeneration and antituberculous drug therapy. An antituberculous drug (rifampicin, RFP) was loaded into a porous scaffold, which composed of a newly designed polylactone, poly(ε-caprolactone)-block-poly(lactic-co-glycolic acid) (b-PLGC) copolymer, and β-tricalcium phosphate (β-TCP). The releasing results demonstrated that RFP could be steadily released for as long as 12 weeks both in vitro and in vivo. During the in vivo experimental period, the drug concentration in tissues surrounding implants was much higher than that in blood which was still superior to the effective value to kill mycobacterium tuberculosis. MC3T3-E1 osteoblasts proliferated well in extracts and co-cultures on composite scaffolds, indicating good cytocompatibility and cell affinity of the scaffolds. The results of a rabbit radius repair experiment displayed that scaffolds have good bone regeneration capacity. The RFP-loaded b-PLGC/TCP composite scaffold thus could be envisioned to be a potential and promising substrate in clinical treatment of bone tuberculosis.
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