关键词: 聚己内酯, 盐酸四环素, 乳液静电纺, 图案化, 药物控释

Abstract: With the continuous innovation and vigorous development of advanced textile technology, new technologies such as emulsion electrostatic spinning, coaxial electrostatic spinning and patterning are gaining popularity. In the field of drug delivery, the nanofiber membrane made by the traditional electrostatic spinning technology as a drug carrier has certain limitations, such as the serious phenomenon of sudden drug release, uneven distribution of drugs in the fiber, and so on. In order to alleviate the phenomenon of sudden drug release, a nanofibrous membrane with a skin-core structure shall be prepared as a solution to effectively encapsulate the drug and maintain the biological activity of the drug molecules by taking advantage of the fact that the core layer of the fiber is not in contact with the outside world. Currently, emulsion electrostatic spinning and coaxial electrostatic spinning can prepare nanofibrous membrane with skin-core structure. Compared with coaxial electrospinning, emulsion electrostatic spinning is simple to operate, and the encapsulation of different drugs/active molecules can be achieved by water-in-oil or oil-in-water. Meanwhile, by patterning to mimic the multi-layered structure of the extracellular matrix (ECM), not only the surface area of the fibrous membrane can be increased to improve its drug release properties, but also the orientation of the fibers can be altered to improve the ability of cell adhesion, growth and differentiation.
In this paper, patterned nanofibrous membranes with polycaprolactone (PCL) as the skin layer and tetracycline hydrochloride (TCH) as the core layer were prepared by emulsion electrostatic spinning. Firstly, a certain amount of PCL was dissolved in 1 mL of hexafluoroisopropanol (HFIP), and then 19.88 mg of Span80 was added as an emulsifier and stirred thoroughly, and afterwards, aqueous solutions of TCH at various concentrations were introduced into the stirring PCL oil-phase solution, creating a mixture with a 6% aqueous-oil phase volume ratio. In the final step, the PCL/TCH patterned nanofibrous membranes were fabricated by using emulsion electrostatic spinning technology, and employing a metal collector with a rhombus-shaped pattern. This was achieved by utilizing a metal lattice receiving device. The performance of the patterned nanofibrous membranes was also analyzed at different drug concentrations. The results showed that the droplet homogeneity of the spinning emulsion was relatively excellent at a drug mass fraction of 2% TCH, which led to a uniform and continuous fiber morphology and an increase in the cumulative drug release rate of 5.17%. Furthermore, the elongation at break of the patterned fibrous membranes improved by 20.31%, and there was a 13.45% increase in the cumulative drug release rate.
In summary, the emulsion electrostatically spun PCL/TCH patterned nanofibrous membrane has good drug release properties. It alleviates the phenomenon of sudden drug release and prolongs the drug release cycle when compared to traditional drug delivery methods, avoiding the defect of frequent wound dressing change. Meanwhile, the patterned treatment provides a favourable environment for cell growth and promotes cell migration and adhesion. Therefore, the membrane has important application potential in drug delivery, wound healing and tissue engineering.