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 morphology 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 Escherichia 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 enhancement 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 performance for the adsorption and desorption of oleuropein compared with MF and RSF. АТСОРПЦИЈА/ДЕСОРПИЦИЈА И БИОФУНКЦИОНАЛНИ КАРАКТЕРИСТИКИ НА ОЛЕУРОПЕИН НАНЕСЕН НА РАЗЛИЧНИ ТИПОВИ МАТРИЦИ ОД СВИЛЕН ФИБРОИНЦелта на ова истражување беше да се испитаат атсорпционите/десорпционите својства на олеуропеин нанесен на различни типови матрици од свилен фиброин: фиброински микровлакна (MF), регенериран фиброин од свила (RSF) и нановлакна од фиброин од свила (NF). Со техниката за електрично предење успешно беа подготвени нановлакната со просечен пресек од 24 до 326 nm. Беше испитано влијанието на концентрацијата на свилениот фиброин, применетиот напон и растојанието меѓу врвот на иглата и колекторската плоча врз морфологијата на NF. Беше утврдено дека атсорпционите капацитети на MF, RSF и NF изнесуваат, соодветно, 104,92, 163,07 и 228,34 mg олеуропеин на грам материјал. Процентот на иницијално атсорбиран олеуропеин што се десорбира изнесуваше соодветно, 86,08, 91,29 и 96,67% за MF, RSF и NF.Дисковите со NF и RSF со нанесен олеуропеин беа подложени на тестови со дифузија на дискот за да се определи нивната антибактериска активност за микроорганизми на Staphylococcus epidermidis (Gram +) и Escherichia coli (Gram -). Резултатите покажаа дека двата материјала имаат антибактериски својства откако ќе им се додаде олеуропеин. Тестовите со третирање на рани од гребнатинки со употреба на олеуропеин ослободен од NF покажаа подобрување на миграцијата не клетките, што укажува дека материјалот има својство на лекување на рани.Се заклучува дека NF може да се користи како биофункционален полимерен материјал кој има подобри својства за атсорпција и десорпција на олеуропеин во споредба...

Silk fibroin nanofibers loaded with hydroxytyrosol from hydrolysis of oleuropein in olive leaf extract

“…After lyophilization, dry crude extracts were obtained. The crude olive leaf extracts were stored in glass bottles in a dark, cool, dry place for further use in experiments [15,20].…”

“…A linear gradient was run from 95 % (A) and 5 % (B) to 75 % (A) and 25 % (B) during 20 min; it changed to 50 % (A) and (B) in 20 min (40 min, total time); in 10 min it changed to 20 % (A) and 80 % (B) (50 min, total time), after re-equilibration in 10 min (60 min, total time) to initial composition. Followed by HPLC analysis, concentration and abundance of oleuropein in samples were determined based on calibration curve of oleuropein standard (purity ≥ 90 %, Extrasynthese, Genay Cedex, France) [15,20].…”

“…In order to prepare aqueous silk fibroin solution 1.2 g degummed silk was dissolved in 20 (v/w) CaCl 2 /distilled water/ethanol (molar ratio 1:8:2) by stirring at 78 °C for 2 hours and then dialyzed at 4-8 °C for three days to remove neutral salts [22]. Aqueous silk fibroin solution obtained as the dialysate was filtered and then freeze dried for 5 days in order to obtain completely dried material in the form of foam as described in Figure 1 [15,20].…”

“…The Syringes and needles used during fabrication of nanofibers were purchased from medical suppliers. Regenerated silk fibroin foams were dissolved in formic acid along with olive leaf extract [15,20].…”

“…The characterization of biomaterials made from silk fibroin nanofibers have been the focus of many studies in the literature [12][13][14]. In the literature, the adsorption/desorption behaviour of oleuropein on different types of silk fibroin matrices including silk fibroin microfibers, regenerated silk fibroin, and silk fibroin nanofibers were also investigated [15]. There are only a few studies about the incorporation of natural compounds into silk fibroin nanofibers in the literature [16,17].…”