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Silk and silk fibroin, the biomaterial from nature, nowadays are being widely utilized in many cutting-edge micro/nanodevices/systems via advanced micro/nanofabrication techniques. Herein, for the first time to our knowledge, we report aqueous multiphoton lithography of diversiform-regenerated-silk-fibroin-centric inks using noncontact and maskless femtosecond laser direct writing (FsLDW). Initially, silk fibroin was FsLDW-crosslinked into arbitrary two/three-dimensional micro/nanostructures with good elastic properties merely using proper photosensitizers. More interestingly, silk/metal composite micro/nanodevices with multidimension-controllable metal content can be FsLDW-customized through laser-induced simultaneous fibroin oxidation/crosslinking and metal photoreduction using the simplest silk/Ag+ or silk/[AuCl4]− aqueous resists. Noticeably, during FsLDW, fibroin functions as biological reductant and matrix, while metal ions act as the oxidant. A FsLDW-fabricated prototyping silk/Ag microelectrode exhibited 104-Ω−1 m−1-scale adjustable electric conductivity. This work not only provides a powerful development to silk micro/nanoprocessing techniques but also creates a novel way to fabricate multifunctional metal/biomacromolecule complex micro/nanodevices for applications such as micro/nanoscale mechanical and electrical bioengineering and biosystems. [ABSTRACT FROM AUTHOR]

Stent implantation has become the preferred revascularization treatment for occlusive blood vessel disease; however, there are occasionally complications resulting in re-narrowing of the treated artery. One approach to overcoming this problem is to establish a confluent monolayer of endothelial cells (ECs) on the stent, and a coating would facilitate the attachment of ECs. Silk fibroin was reported to be used as an ideal coating applied to stent for the culture of human ECs. The aim of the present study is to gain more insight into the influence of the internal microtopographical structure of silk fibroin on cell behavior, such as attachment and growth, and to further investigate its molecular mechanism using human umbilical vein ECs (HUVECs). Our results evaluated the effect of different microtopographical structures on cell behavior. In addition, we analyzed the cell cycle and investigated relevant molecules involved. The results indicated that the microtopographic structure of silk fibroin was associated with EC morphology, attachment and proliferation.

Objective: To Compare the curative effects between titanium mesh coated with or without silk fibroin and in the treatment of larger trachea circumferential defects. To explore the merits of titanium mesh coated with silk fibroin in promoting mucous healing and decreasing related complications., Methods: Twenty-five New Zealand white rabbits were chosen , divided randomly as follows: group one: titanium mesh coated with silk fibroin (n = 12), group two: pure titanium mesh without silk fibroin (n = 12); Titanium mesh coated with silk fibroin and those titanium without silk fibroin were embedded in the anterior of 7-12th tracheal rings respectively, in 2 weeks we removed the anterior and lateral wall of 7-12th tracheal rings about 8 mm x 6mm (more than half ring) and used the two different materials to reconstruct tracheal defects. All these rabbits were euthanized in 4, 8 and 12 weeks and tracheal CT scan, tracheal endoscopy, histopathological examination and scanning electron microscopic examinations were performed. All complications such as death, local inflammation, tracheal stenosis were documented. Group three, leave one normal rabbit as controlled study , removed the anterior and lateral wall of 7-12th tracheal rings, and histopathological examination, scanning electron microscopy were performed as controlled study., Results: The CT scan, tracheal endoscopy of those with silk fibroin showed there was no apparent tracheal stenosis. Histopathological examination showed there was no obvious granulation tissue and scar. The mucous membrane and cilia grow normally. The silk fibroin was not entirely absorbed and the remains showed good biocompatibility. The scanning electron microscopy showed that the cilia grew better and more orderly than that of group two, and in 12 weeks, the cilia became normal. In group two, there were 5 rabbits died in succession from suffocation in 4, 5, 7, 17, 60 days after surgery. All rabbits had local or general subcutaneous emphysema. The CT scan, tracheal endoscopy and pathological examination showed that there were apparent granulation tissue, scar hypertrophy, and tracheal stenosis. The mortality of group two (41.7%) for suffocation compare to that of group one (0), the incidence rate of subcutaneous emphysema in group two (100%) to that of group one (25.0%) and the average cross section stenosis area in group two (18.15 +/- 7.85) mm2 to that of group one (3.15 +/- 1.58) mm2, there are significant statistically differences in these postoperative complications (P <0.05) and stenosis degree (P <0.05) between the two groups. In addition, there was one rabbit died of diarrhea in each group except group three., Conclusions: Silk fibroin and titanium mesh coated with silk fibroin showed good biocompatibility. Titanium mesh coated with silk fibroin used in tracheal reconstruction of rabbits can promote agglutination of mucous membrane and decrease postoperative complications, such as subcutaneous emphysema, tracheostenosis. It may be a prospective biomaterial which can be used in clinical circumferential trachea defect reconstruction.