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The demand for green and non-toxic hair dyes has continued to grow in recent years as the majority of consumers prefer natural and healthy products. There are a series of pigments in nature that are used for color pigmentation and dyeing, such as melanin in animals and curcumin in plants. Accordingly, these nature-inspired novel hair dyes are recognized as having the potential to replace conventional hair dyes for their bio-friendly and less irritating properties. Although several nature-inspired hair dye products and their potential properties, including antistatic, antioxidant, and antibacterial properties, have been proposed, their complex pigmentation mechanisms are not fully understood. The present feature article covers several nature-inspired pigments and strives to summarize the possible pigmentation mechanisms for hair dyeing. A special focus was given to the color-tuning techniques of these novel hair dyes, such as optimization of polymerization, pigment compounding, and tuning of the energy level structure. [ABSTRACT FROM AUTHOR]

Wound healing dressing is increasingly needed in clinical owing to the large quantity of skin damage annually. Excessive reactive oxygen species (ROS) produced through internal or external environmental influences can lead to lipid peroxidation, protein denaturation, and even DNA damage, and ultimately have harmful effects on cells. Aiming to sufficiently contact with the wound microenvironment and scavenge ROS, superabsorbent poly (acrylic acid) and antioxidant poly (ester amide) (PAA/PEA) hybrid hydrogel has been developed to enhance wound healing. The physical and chemical properties of hybrid hydrogels were studied by Fourier-transform infrared (FTIR) absorption spectrum, compression, swelling, degradation, etc. Besides, the antioxidant properties of hybrid hydrogels can be investigated through the free radical scavenging experiment, and corresponding antioxidant indicators have been tested at the cellular level. Hybrid hydrogel scaffolds supported the proliferation of human umbilical vein endothelial cells and fibroblasts, as well as accelerated angiogenesis and skin regeneration in wounds. The healing properties of wounds in vivo were further assessed on mouse skin wounds. Results showed that PAA/PEA hybrid hydrogel scaffolds significantly accelerated the wound healing process through enhancing granulation formation and re-epithelialization. In summary, these superabsorbent and antioxidative hybrid hydrogels could be served as an excellent wound dressing for full-thickness wound healing. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a special residue containing zinc and manganese, spent Zn-Mn batteries cause a serious concern due to their toxicity, abundance and permanence in the environment, and biotechnological recovery of Zn and Mn is one method of recycling thiswaste. In this study identification of the optimum values of the effective parameters in biotechnological processes was investigated using response surfacemethodology. RESULTS: The released dose of Zn andMnwas highly dependent on many parameters. Non-linear equationswere formulated to describe the relationship between bioleaching efficiency of Zn andMn and four important parameters. The optimum parameter values were determined as follows: dose of mixed energy substrates, exogenous-acid pH adjustment, incubating temperature and pulp density of 28 g L-1, 1.9, 33 °C, 9.7%, respectively, for Zn release and 29 g L-1, 1.8, 36.7 °C, 8%, respectively, for Mn mobilization. Themaximum predictive extraction efficiency of Zn andMn was 52.5% and 52.4%, respectively. CONCLUSION: The maximum efficiency of extraction of both Zn andMn reached 50% under optimum conditions after 9 days of bioleaching. Additionally, XRD analyses suggested that Zn andMn existed mainly as Hetaerolite (ZnMn2O4) in the spent Zn-Mn batteries, which gradually disappeared and released Zn2+ and Mn2+ into solution during bioleaching process. [ABSTRACT FROM AUTHOR]