Fibronectin Functionalized Electrospun Fibers by Using Benign Solvents: Best Way to Achieve Effective Functionalization

Abstract

The aim of this study is to demonstrate the feasibility of different functionalization methods for electrospun fibers developed using benign solvents. In particular three different approaches were investigated to achieve the functionalization of poly(epsilon caprolactone) (PCL) electrospun fibers with fibronectin. Protein surface entrapment, chemical functionalization and coaxial electrospinning were performed and compared. Moreover, bilayered scaffolds, with a top patterned and functionalized layer with fibronectin and a randomly oriented not functionalized layer were fabricated, demonstrating the versatility of the use of benign solvents for electrospinning also for the fabrication of complex graded structures. Besides the characterization of the morphology of the obtained scaffolds, ATR-FTIR and ToF-SIMS were used for the surface characterization of the functionalized fibers. Cell adhesion and proliferation were also investigated by using ST-2 cells. Positive results were obtained from all functionalized scaffolds and the most promising results were obtained with bilayered scaffolds, in terms of cells infiltration inside the fibrous structure.

Polycaprolactone Electrospun Fiber Mats Prepared Using Benign Solvents: Blending with Copper(II)‐Chitosan Increases the Secretion of Vascular Endothelial Growth Factor in a Bone Marrow Stromal Cell Line

“…The absorbance increased steadily over 7 days, showing that both for v‐PCL and v‐PCL/CuChi12 are characterized by similar growing curves without statistically significant differences. These values of absorbance are similar to previously reported results74 and are in line with the well‐documented cytocompatibility of polycaprolactone 42,52,74–76. Most importantly, they confirm that the addition of copper(II)‐chitosan does not cause cytotoxicity effects, a problem that might have risen due to copper ions and their possible toxicity 30.…”

“…Prior to electrospinning, v‐PCL was compared in terms of molecular weight ( M w ) distribution to another well‐known similar polymer (nominal 80 kDa polycaprolactone by Sigma‐Aldrich, s‐PCL), which was studied in‐depth in previous work on benign solvents for electrospinning published by the same authors 19,34,46,47. The results of GPC analysis are reported in Table 2 .…”

“…Most interestingly, positive results have been also reported using acetic acid, formic acid, and acetone 40. According to ICH guidelines,41 these solvents belong to Class 3 and are deemed benign at a residual concentration <0.5% (higher amounts may also be acceptable with a proper justification), as also previously described 42. The use of such class of solvents in electrospinning has been recently proposed as an interesting processing method for biomedical polymers 40,43.…”

Fibronectin Adsorption on Electrospun Synthetic Vascular Grafts Attracts Endothelial Progenitor Cells and Promotes Endothelialization in Dynamic In Vitro Culture

“…Another highly relevant ECM protein is fibronectin (FN). Since FN interacts with cells via the integrins α 5 β 1 or α v β 3 , it is a suitable protein for bioactivating a material surface [41][42][43][44]. It is of interest with regard to endothelialization, as it plays a pivotal role in wound healing [45,46].…”

Incorporation of Bioactive Glasses Containing Mg, Sr, and Zn in Electrospun PCL Fibers by Using Benign Solvents

“…Among them, the selection of a proper solvent system plays a crucial role on the features of samples [5,6]. Recently, the standard solvents used for the electrospinning process, which are toxic, such as chloroform, dichloromethane, hexafluoro-2-propanol, dimethylformamide, methanol, or a mixture of them, have been increasingly substituted by less harmful solvents such as acetic acid, formic acid or acetone [7][8][9], which have been defined as benign solvents [10], highlighting the important properties related to prevention of biopolymer denaturation and presence of traces of toxic solvents on the fibers, as well as having a positive environmental impact.…”