Fabrication Of Stimuli-responsive Bio-based Electrospun Fibrous Membranes And Their Applications In Drug Controlled Release

Intelligent drug delivery system has been a research hotspot in the medical field,which can effectively alleviate or even avoid many problems existing in the traditional drug delivery systems,such as high side effects,poor treatment effect,etc.Electrostatic spinning technology has the advantages of simple process,high efficiency,convenient operation and so on.The electrospun fibers have high drug loading efficiency and can effectively keep the biological activity and structural integrity of the encapsulated drugs due to the mild technological conditions in the preparation process,therefore,they have a broad application prospect in the fields of drug carrier and biological tissue engineering.However,there are still many shortcomings in the practical application of many fibrous membrane drug carriers in the diseases treatment such as tumors such as poor biocompatibility,low mechanical strength,poor preparation process trival and drug controlled release effect,which seriously limits the practical application of fiber membranes in the medical field.In order to improve the above problems and realize the actual production and applications of fibrous drug carriers,in this work,a series of bio-based stimuli-responsive electrospun fiber membranes are prepared,their properties and drug controlled release effects are investigated.The main research contents of this paper are as follows:Firstly,polyurethane-polycaprolactone(PU-PCL)coaxial fiber membrane with good biocompatibility and mechanical properties was prepared via coaxial electrostatic spinning technology(employing bio-base material polycaprolactone(PCL)as the main raw material(shell),polyurethane(PU)as the core).The influence of spinning conditions on the coaxial structure of the fiber was studied.The phase transition material was einvestigated and prepared and then was integrated into the nanofibers to endue it the temperature responsiveness,and the temperature responsive PU-PCL/PCM fiber membrane was prepared.The structure,morphology,hydrophilicity and mechanical properties of the fiber membrane were investigated.The results showed that the optimized PU-PCL/PCM fiber membrane had a complete and uniform coaxial structure,and the phase change material was uniformly distributed in the fibers.The tensile stress was increased by four times as much as before,and the tensile strength was also doubled.Then,the drug controlled release effect of PU-PCL/PCM coaxial fiber membrane was discussed.The cytotoxicity of the fiber membrane was evaluated through cell experiments,and the temperature response of the fiber membrane was further verified.Results show that the drug release rate from PU-PCL/PCM fiber membrane under the condition of 39 ? was significantly accelerated,and when the temperature was below 39 ?,the fiber membrane of the drug release rate was slow.In addition,According to the discussion of drug release behavior under 25 ? and 37 ?,it proved that the drug release rate of PU-PCL/PCM was mainly affected by PCM in fiber.When the temperature exceeds the phase transition temperature,PCM in the fiber will undergo phase transition from solid phase to liquid phase,resulting in an increase in the movement path of drug molecules in the fiber and release rate increasing.Furthermore,the temperature responsive release of PU-PCL/PCM is related to the content of phase change material in the fibers,and the controlled release rate of the drug can be changed by changing the content of PCM.The fitting results of the drug curve of the fiber show that the drug release behavior conforms to the biphasic dynamics model.Finally,the hydrophilic cellulose acetate was used to compound with polycaprolactone,GO was prepared by an improved Hummers method.Then,the Near-infrared and temperature responsive GO@ICG/PCM/CA/PCL fiber membranes were prepared by introducing phase transition material and indocinine green and loading GO.The hydrophilicity,mechanical properties and thermal stability of the fiber membrane were studied.The results showed that the hydrophilicity and mechanical properties of the fiber membrane were further improved by loading GO.The mechanical property of the GO@ICG/PCM/CA/PCL membrane was enhanced from 20 MPa to about 50 MPa under the loading of 0.6% graphene.GO@ICG/PCM/CA/PCL fiber membranes can sensitively control the release of drugs under the trigger of NIR laser and show good photodynamic effect and photothermal conversion ability.With the exposure to 808 nm nearinfrared laser,reactive oxygen species can be generated and the temperature of the fiber membranes can be rapidly increased from room temperature to about 50 ?.Moreover,cyclic experiments have proved that the photothermal performance of fiber membrane is relatively stable.With the increase of laser power,the photodynamic and photothermal effects of the fiber membrane become stronger.