Electrospinning for drug delivery systems: potential of the technique

Electrospinning is a technique used to manufacture nano- and submicron fibers based on synthetic or natural polymers. Additionally, biomaterials used in the electrospinning procedure can be modified by bioactive compounds, e.g. peptides or growth factors. The microstructure of the obtained fibrous scaffolds mimics natural extracellular matrix (ECM) environment. The size and the microstructure of the fibrous scaffolds are considered to be suitable for cells adhesion and proliferation. Various design features of the electrospinning device (e.g. the shape of the collector, the shape of the nozzle, the direction of the applied voltage) or electrospinning conditions (e.g. humidity, temperature) allows to control properties of the fibers (their shape, diameter, porosity). Novel structures, such as core-shell fibers, porous fibers attracted wide attention due to their properties and functionalities. Porous fibers or fibers with nanoscaled structures can be obtained in several ways. These methods are mainly focused on using high humidity and highly volatile solvent applied in the electrospinning process. The core-shell structure can be obtained by coaxial electrospinning. That binary fiber has ability to control the release rate of drug enclosed within the shell or core. The drug release profile can be also modified by loading the pharmacological agent either directly to the spinning solution or its post immobilization.This diversity of the electrospun fibers is a reason for non-woven materials to be considered for application as drug carriers. The review of electrospinning methods presented here proves that the control over fibers surface area, morphology and the choice of polymer enable modelling of drug release kinetics.