Comparison of Sericins from Different Sources as Natural Therapeutics against Ulcerative Colitis.

Sericin has become a promising natural anti-inflammatory protein. However, the biological functions of sericins largely depend on their origins; no study has yet been carried out to comparatively investigate the therapeutic effects of sericins from different sources against inflammatory diseases. Herein, we extracted and purified three kinds of sericins, namely silkworm sericin (SS), tussah sericin (TS), and castor silk sericin (CSS). These sericins showed negligible cytotoxicities against colitis-associated cells (colon epitheliums and activated macrophages). Further investigations displayed that these sericins could remarkably downregulate the secreted amounts of TNF-α, promote the recovery of the damaged colonic epithelial barrier, and eliminate endogenous reactive oxygen species in Raw 264.7 macrophages and Caenorhabditis elegans. In vivo experiments demonstrated that chitosan/alginate hydrogel-encapsulating SS could achieve efficient accumulation of SS in the colitis tissues and thereby play a more effective role in relieving ulcerative colitis (UC) than TS and CSS. Our findings collectively demonstrate that SS can be extracted, formulated, and used as a robust therapeutic agent for the oral treatment of UC.

Broadband and high-efficiency spin-polarized wave engineering with PB metasurfaces.

Manipulating circularly polarized (CP) light waves at will are highly important for photonic researches and applications. Recently, while Pancharatnam-Berry (PB) metasurfaces have shown unprecedented capabilities to control CP light, meta-devices constructed so far always suffer from the limitations of low-efficiency and narrow bandwidth. Here, we propose a scheme to construct PB metasurfaces with these two issues well addressed. To verify our idea, two PB meta-devices are designed and fabricated for achieving high-efficiency and broadband photonic spin Hall effect and focusing effect, respectively. Experimental results, in good agreement with full wave simulations, demonstrate the desired functionalities with efficiencies reaching 80% within an ultra-wide frequency band (8.2-17.3GHz). The proposed design scheme is generic and can be extended to high-frequency regimes. Our work can stimulate the realizations of high-performance and broadband PB meta-devices with diversified functionalities.