Silybin-Functionalized PCL Electrospun Fibrous Membranes for Potential Pharmaceutical and Biomedical Applications

Abstract

Silybin is a natural flavonolignan with potential anticancer, antioxidant, and hepatoprotective properties. In the present study, various loadings of silybin (1, 3, and 5 wt%) were encapsulated in poly-ε-caprolactone (PCL) fibers by electrospinning, in order to produce new pharmaceutical composites with improved bioactive and drug delivery properties. The morphological characteristics of the composite fibrous structures were evaluated by scanning electron microscopy (SEM), and the encapsulation efficiency and the release rate of silybin were quantified using a UV-Vis spectrophotometer. The analysis of the membranes' thermal behavior by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed the existence of interaction between PCL and silybin. An investigation of the cytocompatibility of the composite membranes revealed that normal cells displayed an unimpeded proliferation in the respective silybin concentrations; however, tumor cell growth demonstrated a dose-dependent inhibition. Furthermore, an effective antioxidant activity against hydrogen peroxide-induced oxidative stress in HEK-293 cells was observed for the prepared electrospun fibrous mats.

Keywords: antioxidant activity; antitumor activity; cytocompatibility; drug release; electrospinning; encapsulation; polycaprolactone fibers; silybin.

Figure 1

Structures of diasteisomers, silybin (A,B).

Figure 2

Scanning electron micrographs of the electrospun fiber morphology of (a) neat PCL and composite PCL fibers with (b) 1 wt%, (c) 3 wt%, and (d) 5 wt% silybin.

Figure 3

Effect of drug addition on the average diameter of electrospun PCL fibers (error bars denote the standard deviation of the fiber size distribution).

Figure 4

DSC heating thermograms of electrospun PCL fibers with various loadings of silybin (0, 1, 3, and 5 wt%).

Figure 5

TGA curves for neat and composite electrospun PCL fibers (with 0, 1, 3, and 5 wt% silybin) obtained in an inert atmosphere.

Figure 6

In vitro drug release profiles from silybin-encapsulated PCL fibrous membranes (with 1, 3, and 5 wt% silybin) at different time intervals.

Figure 7

Effect of neat and silybin-loaded PCL fibers (with 0, 1, 3, and 5 wt% silybin) on HEK-293 cell viability. Cells were cultured for 48 h in the presence of fibrous membranes, and cell proliferation was evaluated by the MTT assay. Data are expressed as mean ± standard deviation (n = 4–5).

Figure 8

Effect of neat and silybin-loaded PCL electrospun fibers on the cell growth of the carcinoma cell line (HepG2). Cells were cultured for 48 h in the presence of fibrous membranes, and cell viability was evaluated by the MTT assay. Data are expressed as mean ± standard deviation (n = 4–5); * p < 0.05, *** p < 0.001 compared to controls.

Figure 9

Effect of various H₂O₂ concentrations on the viability of human embryonic kidney-293 cells. Cells were treated with H₂O₂ for 12 h. Cell viability was assessed by the MTT assay. Data are expressed as mean ± standard deviation (n = 4–5); * p < 0.05, *** p < 0.001 compared to control (0 mM H₂O₂).

Figure 10

Protective effect of silybin against H₂O₂ oxidative damage on HEK-293 cells. Cells were treated with drug-loaded membranes for 48 h. The viability of cells after H₂O₂ treatment of 12 h was assessed by the MTT assay. Data are expressed as mean ± standard deviation (n = 3–5); * p < 0.05, compared to the H₂O₂-treated cells without protection.