| Human cells are the organic combination of fibers thinner than the diameter of humancells. Electrospun nanofibers are used as biomedical material, these can better simulate thestructure and function of extracellular matrix and are the best template for cell adhesion,differentiation and proliferation. Meanwhile, these can be used for the repair of body tissuesand damaged organs, also be used as wound dressing, etc. The region using electrospun fibersin medical field almost can be combined with the drug delivery and controlled releasetechnology, thus electrospun nanofibers drug controlled-release system is a great potentialproject in biomedical field.The good biocompatibility material cellulose acetate (CA) was used as base material,then the concentration of sustained-release fiber was selected, three different types of drugswere chosen as model drugs, i.e., Anticoagulant drug curcumin (CM), aspirin (AS),antimicrobial drug tannic acid (TA). Single-layer structure CA drug-loaded membrane of10%,20%,30%(w/w of CA) drug content were successfully prepared via blending electrospinning,respectively. The biodegradable polylactic acid (PLA) was outer layer, CA drug-loadedmembrane of20%(w/w) drug content was intermediate layer, multi-layer structure CAdrug-loaded nanofiber membranes of different PLA layer thickness were prepared via step bystep electrospinning. Next, the nanofiber morphology was observed by the scanning electronmicroscopy (SEM), the chemical composition of drug, carrier material and the interactionbetween them were analysed by fourier transform infrared spectroscopy (FT-IR) anddifferential scanning calorimetry (DSC). Furthermore, the properties of fiber membrane, suchas pore size, swelling and weight loss were tested. The results showed that13%was theconcentration of sustained-release fiber, drug-loaded nanofiber surface was smooth and the allhad good uniformity. Three drugs and CA were just simple pure physical mixing, withoutcombination of chemical bonds. Comparing with pure CA, Tmof drug-loaded membranereduced, degree of crystallinity showed some decrease, the swelling and weight loss increased.The presence of drug was in amorphous form. Fiber membrane average pore size decresedwith the increase of PLA layer thickness and more concentrated on small hole.The in vitro drug release property of CA-based drug-loaded membranes wereinvestigated by ultraviolet spectrophotometer method. The influence of drug content, drugtype, temperature, pH, structure and displacement volume on the release behavior werediscussed. The drug release curves were fitted and modified, then done preliminary study onthe relationship between the PLA layer thickness and the drug release rate. The results showedthat CA-based drug-loaded system could controll and sustain the three drugs release well, thefirst0to10h existed a quick release, the release rate reduced subsequently. Drug release rateand cumulative release rate enlarged with the increase of drug content. The rising temperatureaccelerated the drug release rate, which had most obvious effect on TA. There was a bigdifferent in the release rate of three drugs, the order was AS bigger, then TA, last the CM, theywere all more in line with the diffusion dominated Ritger-Peppas release model. When the pHwas5.6, the cumulative release rate of AS, TA were less than the pH was7.4, but CM had the opposite phenomena. The rate were all delayed by the multi-layer structure and the thicker thePLA layer, the slower the rate. The cumulative release rate enlarged with the increase ofdisplacement volume of phosphate buffer.Finally, the efficacy of CA-based drug-loaded membrane were evaluated. Theanticoagulant activity of CM-loaded, AS-loaded membranes were investigated by a series ofexperiments, i.e., recalcification clotting, hemolysis, dynamic clotting test and static plateletadhesion in vitro. The antimicrobial activity of TA-loaded membranes were studiedquantitatively by improved shake flask method. The results indicated that recalcificationclotting time of CM-loaded, AS-loaded membranes prolonged at least57s,27s, respectively,the hemolysis ratio were all less than5%and the activated level of endogenous clotting werelow. The antimicrobial rate towards escherichia coli and staphylococcus aureus was from24.2%and23.2%increased to90%and92%by adding TA in the nanofiber membrane. Thepharmacological effects of CA-based drug-loaded nanofiber delivery system were superior.The existence of PLA layer and the function of high voltage electrospinning didn’t affect thedrug efficacy. |
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