Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of i...Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of implants for controlled drug delivery. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Polymeric nano particulate systems are available in wide variety and have established chemistry. Non toxic, biodegradable and biocompatible polymers are available. Some nano particulate polymeric systems possess ability to cross blood brain barrier. They offer protection against chemical degradation. Smart polymers are responsive to atmospheric stimulus like change in temperature;pressure, pH etc. thus are extremely beneficial for targeted drug delivery. Some polymeric systems conjugated with antibodies/specific biomarkers help in detecting molecular targets specifically in cancers. Surface coating with thiolated PEG, Silica-PEG improves water solubility and photo stability. Surface modification of drug carriers e.g. attachment with PEG or dextran to the lipid bilayer increases their blood circulation time. Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. Polymeric Drug Delivery systems are being utilized for controlled drug delivery assuring patient compliance.展开更多
Although nanocomposites have recently attracted special interest in the tissue engineering area,due to their potential to reinforce scaffolds for hard tissues applications,a number of variables must be set prior to an...Although nanocomposites have recently attracted special interest in the tissue engineering area,due to their potential to reinforce scaffolds for hard tissues applications,a number of variables must be set prior to any clinical application.This manuscript addresses the evaluation of thermo-mechanical properties and of cell proliferation of cellulose nanocrystals(CNC),poly(butylene adipate-co-terephthalate)(PBAT),poly(ε-caprolactone)(PCL)films and their bionanocomposites with 2 wt% of CNC obtained by casting technique.Cellulose nanocrystals extracted from Balsa wood by acid hydrolysis were used as a reinforcing phase in PBAT and PCL matrix films.The films and pure CNC at different concentrations were cultured with osteoblasts MG-63 and the cell proliferation was assessed by AlamarBlue?assay.The thermal-mechanical properties of the films were evaluated by dynamic-mechanical thermal analysis(DMTA).It was found by DMTA that the CNC acted as reinforcing agent.The addition of CNCs in the PBAT and PCL matrices induced higher storage moduli due to the reinforcement effects of CNCs.The cell viability results showed that neat CNC favored osteoblast proliferation and both PBAT and PCL films incorporated with CNC were biocompatible and supported cell proliferation along time.The nature of the polymeric matrix or the presence of CNC practically did not affect the cell proliferation,confirming they have no in vitro toxicity.Such features make cellulose nanocrystals a suitable candidate for the reinforcement of biodegradable scaffolds for tissue engineering and biomedical applications.展开更多
The biocomposite films were prepared from poly(L-lactic acid)and cellulose nanocrystals.To improve interfacial compatibility of hydrophilic cellulose nanocrystals with hydrophobic matrix polymer as well as to provide ...The biocomposite films were prepared from poly(L-lactic acid)and cellulose nanocrystals.To improve interfacial compatibility of hydrophilic cellulose nanocrystals with hydrophobic matrix polymer as well as to provide the osteoconductive properties,cellulose was functionalized with poly(glutamic acid).The modified cellulose nanocrystals were better distributed and less aggregated within the matrix,which was testified by scanning electron,optical and polarized light microscopy.According to mechanical tests,composites filled with nanocrystals modified with PGlu demonstrated higher values of Young’s modulus,elongation at break and tensile strength.Incubation of composite materials in model buffer solutions for 30 weeks followed with staining of Ca^(2+)deposits with Alizarin Red S assay testified better mineralization of materials containing PGlu-modified cellulose nanocrystals as filler.As the result of in vivo experiment,the developed composite materials showed less level of inflammation in comparison with pure polymer matrix and composites filled with non-functionalized cellulose nanocrystals.展开更多
This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (S...This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.展开更多
文摘Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of implants for controlled drug delivery. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Polymeric nano particulate systems are available in wide variety and have established chemistry. Non toxic, biodegradable and biocompatible polymers are available. Some nano particulate polymeric systems possess ability to cross blood brain barrier. They offer protection against chemical degradation. Smart polymers are responsive to atmospheric stimulus like change in temperature;pressure, pH etc. thus are extremely beneficial for targeted drug delivery. Some polymeric systems conjugated with antibodies/specific biomarkers help in detecting molecular targets specifically in cancers. Surface coating with thiolated PEG, Silica-PEG improves water solubility and photo stability. Surface modification of drug carriers e.g. attachment with PEG or dextran to the lipid bilayer increases their blood circulation time. Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. Polymeric Drug Delivery systems are being utilized for controlled drug delivery assuring patient compliance.
文摘Although nanocomposites have recently attracted special interest in the tissue engineering area,due to their potential to reinforce scaffolds for hard tissues applications,a number of variables must be set prior to any clinical application.This manuscript addresses the evaluation of thermo-mechanical properties and of cell proliferation of cellulose nanocrystals(CNC),poly(butylene adipate-co-terephthalate)(PBAT),poly(ε-caprolactone)(PCL)films and their bionanocomposites with 2 wt% of CNC obtained by casting technique.Cellulose nanocrystals extracted from Balsa wood by acid hydrolysis were used as a reinforcing phase in PBAT and PCL matrix films.The films and pure CNC at different concentrations were cultured with osteoblasts MG-63 and the cell proliferation was assessed by AlamarBlue?assay.The thermal-mechanical properties of the films were evaluated by dynamic-mechanical thermal analysis(DMTA).It was found by DMTA that the CNC acted as reinforcing agent.The addition of CNCs in the PBAT and PCL matrices induced higher storage moduli due to the reinforcement effects of CNCs.The cell viability results showed that neat CNC favored osteoblast proliferation and both PBAT and PCL films incorporated with CNC were biocompatible and supported cell proliferation along time.The nature of the polymeric matrix or the presence of CNC practically did not affect the cell proliferation,confirming they have no in vitro toxicity.Such features make cellulose nanocrystals a suitable candidate for the reinforcement of biodegradable scaffolds for tissue engineering and biomedical applications.
基金funded by the Russian Ministry of Education and Science(state contract no.14.W03.31.0014,MegaGrant).
文摘The biocomposite films were prepared from poly(L-lactic acid)and cellulose nanocrystals.To improve interfacial compatibility of hydrophilic cellulose nanocrystals with hydrophobic matrix polymer as well as to provide the osteoconductive properties,cellulose was functionalized with poly(glutamic acid).The modified cellulose nanocrystals were better distributed and less aggregated within the matrix,which was testified by scanning electron,optical and polarized light microscopy.According to mechanical tests,composites filled with nanocrystals modified with PGlu demonstrated higher values of Young’s modulus,elongation at break and tensile strength.Incubation of composite materials in model buffer solutions for 30 weeks followed with staining of Ca^(2+)deposits with Alizarin Red S assay testified better mineralization of materials containing PGlu-modified cellulose nanocrystals as filler.As the result of in vivo experiment,the developed composite materials showed less level of inflammation in comparison with pure polymer matrix and composites filled with non-functionalized cellulose nanocrystals.
文摘This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.
