Adsorption/desorption and biofunctional properties of oleuropein loaded on different types of silk fibroin matrices

Abstract

The objective of this study was to investigate the adsorption/desorption behavior of oleuropein on different types of silk fibroin matrices including silk fibroin microfibers (MF), regenerated silk fibroin (RSF), and silk fibroin nanofibers (NF). Nanofibers with an average diameter of ranging between 24 and 326 nm were successfully prepared using the electrospinning technique. The effects of the silk fibroin concentration, the voltage applied and the distance between needle tip and collector plate on the morphol-ogy of the NF were investigated. The adsorption capacities of MF, RSF and NF were determined as 104.92, 163.07 and 228.34 mg oleuropein per gram of material, respectively. The percentage of initially adsorbed oleuropein that was desorbed was 86.08, 91.29 and 96.67% for MF, RSF and NF, respectively. NF and RSF discs loaded with oleuropein were subjected to disc diffusion assays to determine their antibacterial activity against test microorganisms Staphylococcus epidermidis (Gram +) and Esche-richia coli (Gram -). The results showed that both biomaterials possessed antibacterial properties after loading with oleuropein. Wound scratch assays using oleuropein released from NF revealed an enhance-ment of cell migration, indicating a wound healing property of the material. In conclusion, the NF can be utilized as a biofunctional polymeric material with better perfor-mance for the adsorption and desorption of oleuropein compared with MF and RSF.