Electrosprayed bovine serum albumin-loaded tripolyphosphate cross-linked chitosan capsules: synthesis and characterization.

Bovine serum albumin (BSA)-loaded tripolyphosphate (TPP) cross-linked chitosan capsules were prepared using an electrospraying technique, in which a sufficiently strong electric field was applied to overcome the surface tension of a droplet. A comprehensive investigation was conducted on the effects of concentrations of initial chitosan and TPP solutions, flow rate and BSA/chitosan weight ratio on the physical properties of the mixtures; the morphology, size and yield of the capsules; BSA encapsulation efficiency (EE) and loading capacity (LC); and in vitro release. A high voltage was required to obtain a continuous and stable spray for the mixtures with a high viscosity at high chitosan concentration. The capsules were spherical in shape. Capsule size increased with increasing flow rate, but did not change significantly (p < 0.05) with increases in concentrations of chitosan and TPP. Increasing concentrations of chitosan and TPP solutions increased the yields, while yields decreased with increases in the flow rate. EE and LC increased with increasing chitosan concentration, BSA/chitosan weight ratio and TPP concentration and decreased with increasing flow rate. High EE enhanced the BSA release rate, while a high degree of cross-linking slowed its release.