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Special wettability of biological surfaces usually depends on the unique micro-structures and surface chemistry natures. However, current preparation methods often involve complex processing steps or expensive moulds and have the limited ability to simulate these ordered and elaborate micro-structures. Herein, we report a facile and mould-free approach to fabricate special wetting surfaces by patterning an ordered porous structure with various geometric parameters via one-step 3D printing of Polydimethylsiloxane (PDMS) ink. By adjusting pore structure at sub-millimeter scale, the printed PDMS porous films can present versatile special surface wettabilities such as superhydrophobicity and anisotropic wettability. With the guide of computer program, water contact angles (WCAs) along parallel and perpendicular directionsand anisotropy wetting degree of the printed film can be tailored by controllingprinting speed and filament spacing. Through optimizing the geometrical parameters, a superhydrophobic PDMS filmwith a WCA of about 155° is obtained, which mainly depends on the sub-millimeter scale structure. The superhydrophobicity of the printed porous PDMS film also exhibits excellent durability against thermal aging. Our work demonstrates that the printed superhydrophobic porous film can be used for some attracting applications such as air-breathable water-proofing, water-repellent floating carrier, and no-loss liquid transfer. [ABSTRACT FROM AUTHOR]

Burn is one of the most common types of injuries worldwide, which remains a clinical challenge due to its progressive exacerbation caused by inflammation and edema that impede the growth and differentiation of fibroblast. To solve this problem, in this study, the anti-inflammatory Gelsvirine (Gs), as a specific STING inhibitor for rheumatoid arthritis pain, is used for inflammation control in burn wound healing. Meanwhile, to improve fibroblast migration, proliferation, and differentiation, the natural protein silk fibroin (SF) was used due to its demonstrated capacity to promote the proliferation of epidermal cells and fibroblasts, facilitate collagen synthesis and further improve wound repair. Through our rational design, a functional dressing for the co-delivery of Gs and SF is developed to improve burn wound healing. A multilayer composite dressing of Polycaprolactone(PCL)/Gs-loaded sodium alginate (SA)/SF-gelatin (Gs@SFD) was prepared using the combination of electrospinning and extrusion method, which contained four layers: PCL-dense barrier layer (to prevent infection), SA-hydrogel layer (to load Gs and keep wound moisture), PCL-loosen support layer (to prevent deformation of bioactive layer and to facilitate Gs release into trauma) and SF/gelatin bioactive layer (to contact with trauma and bioactively induce wound healing). Our data showed that the hydrogel layer realized the sustained release of Gs. As a specific inhibitor of STING signaling pathway, the released Gs inhibited the inflammatory response of macrophages and further reduced the fibroblast damage both in vitro and in vivo. In addition, the bioactive layer promoted cell proliferation, facilitated collagen synthesis, and further improved wound healing in animal model of burn trauma. Therefore, this study provides a novel multilayer composite dressing (Gs@SFD) to facilitate burn wound healing via efficient inflammation control with the sustained release of Gs, and improvement on wound healing due to the bioactive components of silk fibroin, which could serve as a potential therapeutic approach in the future. In addition, our multilayer dressing design provides an advanced drug delivery strategy for burn wound healing. [ABSTRACT FROM AUTHOR]