Assembly of particle-fiber composites by electrohydrodynamic jetting using counter-charged nozzles: Independent release control

The optimal design of an electrospun scaffold for tissue engineering is contingent on its functionality to mimic the native extracellular matrix (ECM) as much as possible. Using core-sheath particles for encapsulation, the scaffolds of particle-fiber hierarchical structures could play the dual roles of structural matrix and controlled delivery system of active ingredients. Herein, electrohydrodynamic jetting of countercharged nozzles was investigated to combine fibers and core-sheath particles based on the neutralization phenomenon between electrospun poly(l-lactide-co-d,l-lactide) fibers and electrosprayed poly(lactide-co-glycolide) particles. It was revealed that the key features of particle-fiber composites could be conveniently designed by controlling the composition of the binary mixture of ethyl acetate and benzaldehyde (BA) for electrospraying. With an increase in the BA concentration, the areal density of the particles on the fibers (degree of combination) increased threefold, and the total loading amount of lysozyme (model active ingredient) also increased threefold, while particle size and fiber diameter did not change significantly. The composites prepared from a high BA content case provided sustained release profiles, which are independent from the degradation kinetics of fibers, such that lysozyme could be released for more than a month. The use of a binary solvent mixture for this process seems to be an effective strategy for developing future functional scaffolds for tissue engineering.

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