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A method was developed to fabricate light, water-insoluble silk fibroin nanofibrous aerogels (SNFAs) through solvent welding of lyophilized silk nanofibrous 3D networks at the junction points while converting silk structures from random-coils to β-sheets (water insoluble). Aromatic alcohols, especially phenethyl alcohol (PEA), supported robust solvent welding and the structural conversion of silk. PEA vapor treatment was a better approach than solvent infusion to retain volume, density, and mechanical strength of the SNFAs. The mechanical properties of highly orientated SNFAs were superior to randomly distributed fibers. The SNFAs had a low density (3.5 mg/cm 3 ), high hydrophobicity (140.9°), and a porous surface morphology on the individual nanofibers, resulting in high efficiency and selectivity for absorbing particulate matter and oils. Compared with commonly used inorganic aerogels, the SNFAs developed in this study are biocompatible, easily functionalized, environmentally friendly, and low-cost and therefore have potential for air and water purification, biosensors, drug delivery, and tissue engineering.

treatment for colorectal cancer patients with advanced acute obstruction, high emergent surgical risk, multiple transfer rate, and/or in poor general health. [4] However, postoperative complications and in-stent restenosis caused by tumor ingrowth are major problems for patients undergoing stent displacement. [4][5][6] However, conventional stents made from metal materials only meet the requirements of mechanical expansion and temporary treatment. [5,6] Therefore, development of new intestinal stents with good biocompatibility, degradability, and drug delivery functions is of particular importance. [7] The concept of this type of intestinal stent with drug delivery functions is shown in Figure 1, where the stenosis site can be expanded and the tumor site can be locally treated by drugs released from the stent. 5-Fluorouracil (5-FU) has been used for the treatment of patients with CRC, [2] however, the short half-life (10-20 min), low utilization rate (10-30%), poor sensitivity, and toxicity to normal cells [8,9] are problems. Hence, development of a device that can encapsulate and stabilize 5-FU is important for the improved utilization of the drug to achieve desired clinical outcomes. In previous studies, a drug-loaded polydioxanone weft-knitted stent was developed to treat CRC by slow releasing 5-FU. [2,3] The half maximal inhibitory concentration (IC 50 ) and the median lethal dose (LD 50 ) demonstrated that these drug-loaded membranes had better antitumor effectsIn-stent restenosis caused by tumor ingrowth is a major problem for patients undergoing stent placement because conventional stents often lack sustainable antitumor capabilities. The aim of this work is to develop a silk fibroin (SF)based nanofibrous membrane that is loaded with combined-therapy drugs by using electrospinning technologies, which is further coated on a polydioxanone (PDO) stent and used for the treatment of colorectal cancer (CRC). In order to improve treatment effectiveness, a combination of therapeutic drugs, i.e., curcumin (CUR) and 5-fluorouracil (5-FU), is dissolved into SF solution and then eletrospun onto the surface of the PDO stent. The morphology, secondary structure, and in vitro drug release profiles of the membranes are characterized. The antitumor efficacy is assessed in vitro and in vivo using a human CRC cell line and normal cells, and tumor-bearing nude mice. In vitro and in vivo studies on the nanofibrous memembrane-coating demonstrate improved antitumor effects for the CUR/5-FU dual drug system which can be attributed to cell cycle arrest in the S phase in association with induced apoptosis in tumor cells by blocking signal transducer and activator of transcription 3 (Stat3) and nuclear factor kappa beta (NF-kB) signaling pathways, suggesting potential in the treatment of CRC in the future.

Wound dressings are important for wound repair. The morphology of the biomaterials used in these dressings, and in particular, the pore structure affects tissue regeneration by facilitating attachment and proliferation of cells due to the hierarchical multiscale, water absorbance, and nutrient transport. In the present study, silk fibroin (SF) sponges with walls containing nanopores (SFNS) were prepared from SF nanoparticles generated during the autoclaving of SF solutions, followed by leaching the SF nanoparticles from the freeze-dried sponges of SF. The nano/microporous structure, biofluid absorbance, and porosity of the SF sponges with and without nanopores were characterized. In vitro cell proliferation, in vivo biocompatibility, and wound healing were evaluated with the sponges. The results demonstrated that SFNS had significantly increased porosity and water permeability, as well as cell attachment and proliferation when compared with SF sponges without the nanopores (SFS). Wound dressings were assessed in a rat skin wound model, and SFNS was superior to SFS in accelerating wound healing, supported by vascularization, deposition of collagen, and increased epidermal thickness over 21 days. Hence, such a dressing material with a hierarchical multiscale pore structure could promote cell migration, vascularization, and tissue regeneration independently without adding any growth factor, which would offer a new strategy to design and engineer better-performed wound dressing.

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