Preparation Of PLA-based Composite Nanofibrous Materials And Its Sustained Drug Release Property

Due to the high porosity,surface to mass ratio and interconnecting pore stucture,electrospun nanofibers could be used in various applications of biomedical field,air filtration,water treatment,personal protection and electrode materials.Furthermore,the elctrospun nanofiber possesses the characteristics of easy to load drugs and mimicking the extracelluar matix,which are extremely suitable for the applications in tissue engineering materials and drug delivery.The mechanical performances of nanofiber membranes are not satisfactory.When nanofiber was used directly as drug delivery carriers,“burst release”was inevitably occurered and sustained drug release properties were also unrealizable.In this paper,the following studies are carried out on the optimization about mechanical and drug release properties for electrospun nanofiber membranes.Firstly,the model drug of tetracycline hydrochloride（TCH）was loaded onto the surface of hydroxyapatite through the physical absorption to obtain the TCH/PLA nanoparticles.The TCH/PLA nanoparticles were blended with the PLA solution to generate TCH/HAP/PLA composite nanofibers by the electrospinning technique.Based on this method,the bi-carriers nanofiber system was fabricated.The mechanical test result shows that the mechanical properties of PLA nanofiber were increased dramatically after adding the HAP and TCH/HAP nanoparticles.The Young’s modulus and tensile strength increased up to 170%and 126%for the TCH/HAP/PLA composite nanofiber membrane.The enhanced mechanical performance of TCH/HAP/PLA nanocomposites can be attributed to the good dispersion of the TCH/HAP nanoparticles in the PLA matrix,which promoted to the transfer the stress from composite nanofiber matrix to nanofillers.The in vitro drug release results show that the designed bi-carriers nanofiber system can effctly reduce the“burst release”and archieve sustained drug release for 9 days.Secondly,the mesoporous Fe₃O₄-COOH nanoparticles with uniformed size and conttrollable morphology was prepared by solvothermal method.The positively charged TCH was combined with Fe₃O₄-COOH nanoparticles though electrostatic interactiontoobtaintheTCHloadedFe₃O₄-COOHnanoparticles（TCH/Fe₃O₄-COOH）.The TCH/Fe₃O₄-COOH nanoparticles were then blended with the PLA solution to generate TCH/Fe₃O₄-COOH/PLA composite nanofibers by the electrospinning technique.Based on this method,the bi-carriers nanofiber system was fabricated.The Young’s modulus and tensile strength increased up to 191%and150%,respectively,for the TCH/Fe₃O₄-COOH/PLA composite nanofiber membrane.The enhanced mechanical performance of TCH/Fe₃O₄-COOH/PLA nanocomposites can be attributed to the good dispersion of the TCH/Fe₃O₄-COOH nanoparticles in the PLA matrix,which is beneficial for the effective filler-matrix stress transfer the stress.The in vitro drug release results show that the designed bi-carriers nanofiber system can effectively reduce the“burst release”and archieve sustained drug release for 14days.Finally,the water-in-oil（W/O）emulsion stabilized by Span 80 is comprised of aqueous tetracycline hydrochloride solution（water phase）and PLA solution（oil phase）.Followed by electrospinng process,the stable emulsion was fabricated into core-shell nanofiber.Based on this method,the core-shell structured nanofiber drug system was obtained to reduce the“burst release”and archieve sustained drug release.The mechanical test result shows that the Young’s modulus and tensile strength increased up to 144%and 157%for the E-TCH/PLA composite nanofiber membrane.The enhanced mechanical performance can be attributed to the similar strengthen effect of short fiber（such as carbon nanofiber）caused by the small molecular of Span80.The in vitro drug release results show that the core-shell structured nanofiber can effctly reduce the“burst release”and archieve sustained drug release for 16 days.Thus,core-shell structure nanofiber with appropriate mechanical properties and sustained antibacterial properties can be obtained.