Bamboo, as a potential ecological building material, has attracted a lot of attention, due to its wide distribution, more than 1000 species, short growth cycle of 3–5 years, three times the carbon dioxide adsorption of other plants, and tensile strength comparable to steel or concrete. The major challenges of bamboo are the single color and poor anti-microbial corrosion, based on the intrinsic nature of polysaccharides such as cellulose. In this work, a novel bamboo composite material that exhibits a rich variety of colors (red wine, light yellow, coffee, white, black), excellent color retention, and anti-microbial corrosion for 14 days under a relative humidity of 60–95% is prepared by an easy-to-scale chemical grafting method. Oxidation treatment is the basic condition for bamboo to obtain bright colors, and the substitution reaction of the carbon heterocyclic ring of polysaccharide molecules is the inherent reason for bamboo dyeing. For instance, the bamboo treated with nitric acid presents a bright red wine color, and C=N, –NO 2 functional groups are detected. Polyethylene glycol filled in the three-dimensional network avoids the water-soluble nutrients from emigrating to the surface of bamboo. The interruption of the continuous supply route allows the modified bamboo to obtain excellent antibacterial performance. Bright color and anti-microbial corrosion characteristics make the modified bamboo as a green building material has more potential applications. Graphical abstract
Xinmei Sha,Yidan Zhang,Yue Li,Runxuan Chen,Haotong Zhang,Demei Meng,Hai Chen,Rui Yang
Ferritin is a cage-like protein with modifiable outer and inner surfaces. To functionalize ferritin with preferable carrier applications, caffeic acid was first covalently bound to the soybean ferritin outer surface to fabricate a caffeic acid–ferritin complex (CFRT) by alkali treatment (pH 9.0). A decreased content of free amino acid (0.34 μmol/mg) and increased polyphenol binding equivalent (63.76 nmol/mg) indicated the formation of CFRT (ferritin/caffeic acid, 1:80). Fluorescence and infrared spectra verified the binding of caffeic acids to the ferritin structure. DSC indicated that the covalent modification enhanced the thermal stability of CFRT. Besides, CFRT maintained the typically spherical shape of ferritin (12 nm) and a hydration radius of 7.58 nm. Moreover, the bioactive colorant betanin was encapsulated in CFRT to form betanin-loaded CFRT (CFRTB), with an encapsulation rate of 15.5% (w/w). The betanin stabilities in CFRTB were significantly improved after heat, light, and Fe3+ treatments, and its red color retention was enhanced relative to the free betanin. This study delves into the modifiable ferritin application as nanocarriers of dual molecules and gives guidelines for betanin as a food colorant.
危险品化学品经营许可证（带存储）