The pursuit of sustainable functional materials requires development of materials based on renewable resources and efficient fabrication methods. Hereby, we fabricated all-polysaccharides multilayer films using cationic guar gum (CGG) and anionic cellulose nanofibrils (i.e., TEMPO-oxidized cellulose nanofibrils, TOCNs) through a layer-by-layer casting method. This technique is based on alternate depositions of oppositely charged water-based CGG and TOCNs onto laminated films. The resultant polyelectrolyte multilayer films were transparent, ductile, and strong. More importantly, the self-standing films exhibited excellent gas (water vapor and oxygen) and oil barrier performances. Another outstanding feature of these resultant films was their resistance to various organic solvents including methanol, acetone, N,N-dimethylacetamide (DMAc) and tetrahydrofuran (THF). The proposed film fabrication process is environmentally benign, cost-effective, and easy to scale-up. The developed CGG/TOCNs multilayer films can be used as a renewable material for industrial applications such as packaging.

Construction of anti-adhesive polypropylene meshes through the in situ copolymerization grafting of poly(ethylene glycol) methacrylate and dopamine methacrylamide.

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Polypropylene (PP) mesh has been used successfully for a long time in clinical practice as an impressive prosthesis for ventral hernia repair. To utilize a physical barrier for separating mesh from viscera is a general approach for preventing adhesions in clinical practice. However, a serious abdominal adhesion between the mesh and viscera can possibly occur post-hernia, especially with the small intestine; this can lead to a series of complications, such as chronic pain, intestinal obstruction, and fistula. Thus, determining how to prevent abdominal adhesions between the mesh and viscera is still an urgent clinical problem. In this study, a dopamine-functionalized polysaccharide derivative (oxidized-carboxymethylcellulose-g-dopamine, OCMC-DA) was synthesized; this was blended with carboxymethylchitosan (CMCS) to form a hydrogel (OCMC-DA/CMCS) in situ at the appropriate time. The physical and chemical properties of the hydrogel were characterized successfully, and its excellent biocompatibility was presented by the in vitro cell test. The combination of this hydrogel and PP mesh was used in laparoscopic surgery for repairing the abdominal wall defect, where the hydrogel could become fixed in situ on the PP mesh to form an anti-adhesion gel-mesh. The results showed that the gel-mesh could prevent abdominal adhesions effectively in the piglet model. Moreover, the histology and immunohistochemical staining proved that the gel-mesh could effectively alleviate the inflammation reaction and deposition of collagen around the mesh, and it did not disturb the integration between mesh and abdominal wall. Thus, the gel-mesh has superior tissue compatibility.

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Simple, fast, and accurate detection of food freshness is of considerable significance to ensure food safety. The pH values of foods can be good indicators of their freshness, which can be used for real-time detection of food quality. Herein, we fabricated a pH-sensing film for flexible smart labels based on hydroxypropyl guar (HPG), cellulose nanocrystal (CNC), 1-butyl-3-methylimidazolium chloride (BmimCl), a kind of ionic liquid (IL), and anthocyanin (Anth). We investigated the structure, optical properties, and mechanical strength of the composite films. These films can be used to detect ammonia (NH 3 ) generated from seafood during storage by pH-sensing capability and monitor the real-time freshness of seafood. The HPG/CNC/IL/Anth film exhibited several advantages, such as wide color-change range, easy identification, high sensitivity, good reversibility, excellent stability, and low detection limit. The pH-sensing films can function as flexible smart labels for real-time, visual, and accurate detection of food freshness in cold chain logistics and other fields.

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