Controlled release of ampicillin from coaxially electrospun bovine serum albumin nanofibers

In this study, a controlled drug release platform was developed by using natural protein, namely bovine serum albumin (BSA). Drug-loaded amyloid-like Bovine Serum Albumin (AL-BSA) nanofibers were prepared by modified coaxial electrospinning process. A hydrophilic drug, ampicillin (Amp) was selected as a model drug. After the shell and core solutions prepared at certain rates, fiber production has been carried out smoothly and continuously without any plugging on the needle tip. By single-needle electrospinning of the core, core (C) membranes were produced and two types of core/shell membranes were produced via coaxial electrospinning: Core/shell 1 and Core/shell 2 (CS1 and CS2). Glutaraldehyde was used as a cross-linking agent for C membrans ( GA-C) to reduce the burst release. Scanning electron microscopy (SEM) images demonstrated that C, CS1 and CS2 nanofibers were smooth and homogeneous. Transmission electron microscopy (TEM) verified that the membranes consisted of nanofibers with core-shell structure. Fourier transform infrared spectra (FTIR) of drug-loaded AL-BSA nanofiber showed that both the shell and the core matrix had good compatibility with Amp due to the formation of hydrogen bond between drug and matrix. The contact angle measurements showed that AL-BSA membranes were hydrophobic character. In vitro Amp release tests showed that C and GA-C followed Fickian transport, which was close to zero-order kinetics whereas CS1 and CS2 showed typical biphasic release behaviors, including the initial burst release and the sustained release stages. Nanofibers produced by core-shell electrospinning compared to single electrospinning, AL-BSA coated core-shell nanofibers had less initial burst release and longer drug release periods. The results from the zone of inhibition test of the AL-BSA against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli indicated that the released ampicillin retained its effectiveness after the electrospinning process and the amount of drug in the AL-BSA membrane was sufficient for bacterial inhibition.