In the present study, chitosan and polyvinyl alcohol(PVA) were blended with different concentrations of sodium montmorillonite(Na^+MMT) clay solution by a solvent casting method. X-ray diffraction and transition elect...In the present study, chitosan and polyvinyl alcohol(PVA) were blended with different concentrations of sodium montmorillonite(Na^+MMT) clay solution by a solvent casting method. X-ray diffraction and transition electron microscope results show that the film properties are related to the co-existence of Na^+MMT intercalation/exfoliation in the blend and the interaction between chitosan–PVA and Na^+MMT. 5-Fluorouracil(5-FU) was loaded with chitosan–PVA/Na^+MMT nanocomposite films for in vitro drug delivery study. The antimicrobial activity of the chitosan–PVA/Na^+MMT films showed significant effect against Salmonella(Gram-negative) and Staphylococcus aureus(Gram-positive), whereas5-FU encapsulated chitosan–PVA/Na^+MMT bio-nanocomposite films did not show any inhibition against bacteria. Our results indicate that combination of a flexible and soft polymeric material with high drug loading ability of a hard inorganic porous material can produce improved control over degradation and drug release. It will be an economically viable method for preparation of advanced drug delivery vehicles and biodegradable implants or scaffolds.展开更多
The present study explores the in situ fabrication of chitosan-poly(vinyl alcohol)-silver nanocomposite films in view of their increasing applications as antimicrobial packaging, wound dressing and antibacterial mater...The present study explores the in situ fabrication of chitosan-poly(vinyl alcohol)-silver nanocomposite films in view of their increasing applications as antimicrobial packaging, wound dressing and antibacterial materials. The reduction of silver ions into silver nanoparticles (AgNPs) is achieved in acidic solution of chitosan (C) and poly (vinyl alcohol) (PVA) using their functional groups (-OH, -COOH, -NH2 groups). The presence of silver nanoparticles in the chito-san-PVA film is confirmed by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy and X-ray Dif-fraction (XRD) analysis. The Scanning Electron Microscopic (SEM) images illustrate the presence of embedded silver nanoparticles throughout the films. In addition, the formed silver nanoparticles have an average particle size of ~ 16.5 nm as observed by Transmission Electron Microscopy (TEM). The anti-microbial and anti-fungal activity of the chitosan-PVA silver nanoparticle films have demonstrated significant effects against Escherichia coli (E. coli), Pseudomonas, Staphylococcus, Micrococcus, Candida albicans, and Pseudomonas aeruginosa (P. aeruginosa). To improve further their therapeutic efficacy as anti-microbial agents, curcumin encapsulated chitosan-PVA silver nanocomposite films are developed which showed enormous growth inhibition of E. coli compared to curcumin and chitosan-PVA silver nanoparticles film alone. Therefore, the present study clearly provides novel antimicrobial films which are potentially useful in preventing/treating infections.展开更多
A new type ofnanofibrous structure from chitosan bearing carboxymethyl-β-cyclodextrin （CS-g-β-CD） as a novel drug delivery system was synthesized by grafting carboxymethyl-β-cyclodextrin （CM β-CD） onto chitos...A new type ofnanofibrous structure from chitosan bearing carboxymethyl-β-cyclodextrin （CS-g-β-CD） as a novel drug delivery system was synthesized by grafting carboxymethyl-β-cyclodextrin （CM β-CD） onto chitosan （CS） in the presence of water soluble 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide （EDC） as the condensing agent and N-hydroxysuccinimide （NHS）. Defect free mats containing CS-g-β-CD have been fabricated using electrospirming of an aqueous solution of poly（vinyl alcohol） （PVA）/CS-g-β-CD blends. The morphology and diameter of the electrospun nanofibers were examined by scanning electron microscopy （SEM）. The average fiber diameter was in the range of 130-210 run. SEM images showed that the morphology and diameter of the nanofibers were mainly affected by weight ratio of the blend at constant applied voltage. The results revealed that increasing CS-g-β-CD content in the blends decreases the average fiber diameter. It was observed that the PVA/CS-g-β-CD nanofibrous mat provided a slower release of the entrapped drug in compare to PVA/CS nanofibrous mat.展开更多
基金the Tshwane University of Technology for their financial support
文摘In the present study, chitosan and polyvinyl alcohol(PVA) were blended with different concentrations of sodium montmorillonite(Na^+MMT) clay solution by a solvent casting method. X-ray diffraction and transition electron microscope results show that the film properties are related to the co-existence of Na^+MMT intercalation/exfoliation in the blend and the interaction between chitosan–PVA and Na^+MMT. 5-Fluorouracil(5-FU) was loaded with chitosan–PVA/Na^+MMT nanocomposite films for in vitro drug delivery study. The antimicrobial activity of the chitosan–PVA/Na^+MMT films showed significant effect against Salmonella(Gram-negative) and Staphylococcus aureus(Gram-positive), whereas5-FU encapsulated chitosan–PVA/Na^+MMT bio-nanocomposite films did not show any inhibition against bacteria. Our results indicate that combination of a flexible and soft polymeric material with high drug loading ability of a hard inorganic porous material can produce improved control over degradation and drug release. It will be an economically viable method for preparation of advanced drug delivery vehicles and biodegradable implants or scaffolds.
文摘The present study explores the in situ fabrication of chitosan-poly(vinyl alcohol)-silver nanocomposite films in view of their increasing applications as antimicrobial packaging, wound dressing and antibacterial materials. The reduction of silver ions into silver nanoparticles (AgNPs) is achieved in acidic solution of chitosan (C) and poly (vinyl alcohol) (PVA) using their functional groups (-OH, -COOH, -NH2 groups). The presence of silver nanoparticles in the chito-san-PVA film is confirmed by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy and X-ray Dif-fraction (XRD) analysis. The Scanning Electron Microscopic (SEM) images illustrate the presence of embedded silver nanoparticles throughout the films. In addition, the formed silver nanoparticles have an average particle size of ~ 16.5 nm as observed by Transmission Electron Microscopy (TEM). The anti-microbial and anti-fungal activity of the chitosan-PVA silver nanoparticle films have demonstrated significant effects against Escherichia coli (E. coli), Pseudomonas, Staphylococcus, Micrococcus, Candida albicans, and Pseudomonas aeruginosa (P. aeruginosa). To improve further their therapeutic efficacy as anti-microbial agents, curcumin encapsulated chitosan-PVA silver nanocomposite films are developed which showed enormous growth inhibition of E. coli compared to curcumin and chitosan-PVA silver nanoparticles film alone. Therefore, the present study clearly provides novel antimicrobial films which are potentially useful in preventing/treating infections.
文摘A new type ofnanofibrous structure from chitosan bearing carboxymethyl-β-cyclodextrin （CS-g-β-CD） as a novel drug delivery system was synthesized by grafting carboxymethyl-β-cyclodextrin （CM β-CD） onto chitosan （CS） in the presence of water soluble 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide （EDC） as the condensing agent and N-hydroxysuccinimide （NHS）. Defect free mats containing CS-g-β-CD have been fabricated using electrospirming of an aqueous solution of poly（vinyl alcohol） （PVA）/CS-g-β-CD blends. The morphology and diameter of the electrospun nanofibers were examined by scanning electron microscopy （SEM）. The average fiber diameter was in the range of 130-210 run. SEM images showed that the morphology and diameter of the nanofibers were mainly affected by weight ratio of the blend at constant applied voltage. The results revealed that increasing CS-g-β-CD content in the blends decreases the average fiber diameter. It was observed that the PVA/CS-g-β-CD nanofibrous mat provided a slower release of the entrapped drug in compare to PVA/CS nanofibrous mat.
