ABSTRACT
The purpose of this research was to investigate chitosan-based composite sponge containing silver nanoparticles (Ag NPs) for wound dressing application. The composite sponge was prepared by a freeze-drying technique, and then immersed in AgNO3 solution with different concentration and autoclaved at 15 psi, 121 degrees C for 15 min for the formation of Ag NPs. The composite sponge containing Ag NPs was characterized by UV-vis spectra, XRD and SEM. The characteristic peaks of Ag in the UV-vis spectra and the XRD pattern revealed the formation of Ag-NPs. The SEM image showed that the silver particles homogeneously distributed on the surface of the composite sponge with an average particle diameter of about 60-80 nm. The contents of silver determined by ICP Single-channel scanning spectrometer were 0.032, 0.096 and 0.166 weight percentage, respectively, when the composite sponge was correspondingly treated with AgNO3 at concentrations of 0.1, 0.25 and 0.5 mM. The results of enzymic degradation in vitro indicated that the Ag-NPs could obviously promote the degradation of the composite sponge. The bacteriostatic and bactericidal properties of the new sponge were preliminarily studied in vitro by using S. aureus E. coli and P. aeruginosa as test microorganisms. The test results demonstrated that the new Ag NPs-loaded chitosan-based composite sponge possessed not only bacteriostatic, but also bactericidal activity against these test bacteria.
Subject(s)
Anti-Bacterial Agents/chemistry , Bandages , Chitosan/chemistry , Metal Nanoparticles/chemistry , Silver/chemistry , Anti-Bacterial Agents/administration & dosage , Bacteria/drug effects , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Silver/administration & dosage , Spectrophotometry, Ultraviolet , X-Ray DiffractionABSTRACT
The model drug, 5-fluorouracil (5-FU) was loaded into the poly(N-isopropylacrylamide) (PNIPA) hydrogel at 25 degrees C, then the drug-loaded, swollen hydrogel sample was carefully enveloped in the dialysis bag to form a novel thermo-responsive drug delivery system (DDS). The concentration of released 5-FU was monitored at 266 nm on the UV spectrophotometer. We found that this novel DDS provides a positive drug release pattern and the drug, 5-FU, was released faster at the increased temperature (37 degrees C, >25 degrees C) than the one at the decreased temperature (10 degrees C, <25 degrees C). This was attributed to the double control of the thermo-sensitivity of the hydrogel matrix and the dialysis membrane. By employing the fast response PNIPA hydrogel instead of the conventional hydrogel in this novel DDS, we can further control the drug release rate and/or drug release amount etc., without changing the positive, thermo-responsive drug release pattern.
