•Zein superhydrophobic/hydrophobic nanofibrous network was formed by electropinning.•The highest WCA of the zein electrospun nanofibrous network (ZENN) could reach 153.6°.•Both the zein concentration and applied voltage had effects on the surface hydrophobicity.•ZENN could mimic the extracellular matrix to support the cell growing.Superhydrophobic/hydrophobic nanofibrous networks have attracted much attention because of their potential applications in tissue engineering. Cell growth in the scaffold of tissue engineering can be controlled by the hydrophobicity of the scaffold. The superhydrophobic/hydrophobic surfaces are usually made from synthesized polymers, which generally are not biocompatible and biodegradable and, thus, not suitable for biomedical applications. Zein is an amphiphilic protein from corn, and it is potential for hydrophobic surface formation. This work aims to make zein superhydrophobic/hydrophobic nanofibrous network using electrospinning. The formed zein networks show high hydrophobicity with the water contact angles ranging from 130.5 ± 1.0° to 153.6 ± 2.1°. The cell attachment and growth on the zein networks are studied. It is observed that the amount of the cells attached and grown in the zein nanofibrous networks are higher than the ones on the conventional zein casting films. The results indicate that the electrospun zein nanofibrous network has great potential as scaffold in tissue engineering to support cell growth and tissue regeneration.

Superhydrophobic/hydrophobic surfaces have attracted wide attention because of their broad applications in various regions, including coating, textile, packaging, electronic devices, and bioengineering. Many studies have been focused on the fabrication of superhydrophobic/hydrophobic surfaces using natural materials. In this paper, superhydrophobic/hydrophobic surfaces were formed by an amphiphilic natural protein, zein, using electrospinning. Water contact angle (WCA) and scanning electron microscopy (SEM) were used to characterize the hydrophobicity and surface morphology of the electrospun structures. The highest WCA of the zein electrospun surfaces could reach 155.5 ± 1.4°. To further understand the mechanism of superhydrophobic surface formation from amphiphiles using electrospinning, a synthetic amphiphilic polymer was selected, and also, a method similar to electrospinning, spray drying, was tried. The electrospun amphiphilic polymer surface showed a high hydrophobicity with a WCA of 141.4 ± 0.7°. WCA of the spray-dried zein surface could reach 125.3 ± 2.1°. The secondary structures of the zein in the electrospun film and cast-dried film were studied using ATR-FTIR, showing that α-helix to β-sheet transformation happened during the solvent evaporation in the cast drying process but not in the electrospinning process. A formation mechanism was proposed on the basis of the orientation of the amphiphiles during the solvent evaporation of different fabrication methods. The droplet-based or jet-based evaporation during electrospinning and spray drying led to the formation of the superhydrophobic/hydrophobic surface by the accumulation of the hydrophobic groups of the amphiphiles on the surface, while the surface-based evaporation during cast drying led to the formation of the hydrophilic surface by the accumulation of the hydrophilic groups of the amphiphiles on the surface.

Hydrophobic surfaces are of interest in many electronic devices and biomedical applications for the control of wettability and adsorption behavior. Most of the artificial hydrophobic surfaces are not biodegradable, renewable, or mechanically flexible and are often expensive, which limits their potential applications. Natural materials are better choices; however, most of them are hydrophilic and water-absorbing and general modification of molecules, expensive equipment and fluorine-containing coating cannot be avoided. In contrast, zein, a major protein of corn and an amphiphilic, biodegradable, renewable, flexible, inexpensive biopolymer, which is abundantly present in nature, satisfies all the above requirements. The objective of this work is to form a hydrophobic surface through a facile and inexpensive method of self-assembly monolayer (SAM) assisted evaporation-induced self-assembly (EISA) by zein. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used for the characterization of surface morphology and surface elements. Water contact angle (WCA) was applied to characterize the hydrophobicity of films. Both zein concentration and solvent concentration had effects on the hydrophobicity of the film. A film with high hydrophobicity was formed by size controlled SAM assisted EISA. The WCA of the zein hydrophobic film reached 126°.