The excessive reactive oxygen species (ROS) and hypoxia deteriorate the inflammation-related diseases such as myocardial infarction (MI), and thereby deter the normal tissue repair and recovery and further lead to severe fibrosis and malfunction of tissues and organs. In particular, the MI has become one of the leading causes of death nowadays. In this study, a novel type of injectable hydrogel with dual functions of ROS scavenging and O-2 generating is fabricated for MI treatment in vivo. The hydrogel is formed within 3 s from the synthetic ROS-cleavable hyperbranched polymers and methacrylate hyaluronic acid (HA-MA) under UV-irradiation. Addition of biocompatible and applicable catalase in vivo enables the further transition of H2O2, a major type of ROS, to O-2 and H2O. Results of rat MI model demonstrate that this hydrogel can significantly remove excessive ROS, inhibit cell apoptosis, increase M2/M1 macrophage ratio, promote angiogenesis, reduce infarcted area, and improve cardiac functions. With the appropriate degradation rate, simple structure and composition without cell seeding, and very excellent MI therapeutic effect, this ROS scavenging and O-2 generating hydrogel has a great promise to be applied clinically.

Landfilling of food waste in the United States is a source of unutilized resources and environmental risks. As cities look to divert food waste from landfills, microorganisms may hold the answer. Purple non-sulfur bacteria are a group of microorganisms that can treat and extract resources from food waste to produce a protein supplement for animal feed. This study includes a life cycle assessment to compare four food waste management scenarios: purple non-sulfur bacteria production offsetting soybean meal production, purple non-sulfur bacteria production offsetting fishmeal and carotenoid production, anaerobic digestion, and landfilling (status quo). Purple non-sulfur bacteria offsetting soybean meal production resulted in significantly reduced environmental impacts compared to landfilling. Specifically, the eutrophication impact, land use, and water use for the soybean meal offset scenario were 141 kg N equivalents/day, 96 ha, and 120,000 L/day lower than landfilling, respectively. However, the low value of soybean meal limits the economic viability of this scenario. When high-value fishmeal and carotenoids were the offset products, there was an increase in value of $0.023/kg FW treated over landfill disposal of food waste. Offset fishmeal and carotenoids are not without environmental tradeoffs, most significantly with respect to eutrophication and global warming. This study then demonstrated that determining maximal growth rates to a PNSB photobioreactor, growing PNSB microorganisms on sunlight, and identifying the degree to which PNSB carotenoids can replace carotenoids in fish food were plausible lines of research to improve environmental and/or economic viability of the process. The life cycle assessment developed here can inform decision making for food waste management and guide research to improve purple non-sulfur bacteria production. (C) 2020 Elsevier Ltd. All rights reserved.