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Independent research experiences in sustainable chemistryThe Research Experiences for Undergraduates (REU) programme in the Department of Chemistry at Michigan State University was created to inform students majoring in chemistry, biochemistry and chemical engineering about key societal sustainability challenges and to provide graduate-level independent research experiences that address aspects of these challenges. The REU programme exposes students to how sustainable practices are impacting research and technology development in chemistry and chemical engineering. The 10-week summer programme introduces students, many of whom are engaging in graduate-level research for the first time, to the multiple steps in the research process: (i) formulate research questions and a hypothesis, (ii) create a research design, (iii) execute an experimental plan, (iv) data analysis and interpretation, and (v) report out on the findings and their significance. 

Cholinergic signaling, i.e., neurotransmission mediated by acetylcholine, is involved in a host of physiological processes, including learning and memory. Cholinergic dysfunction is commonly associated with neurodegenerative diseases, including Alzheimer’s disease. In the gut, acetylcholine acts as an excitatory neuromuscular signaler to mediate smooth muscle contraction, which facilitates peristaltic propulsion. Gastrointestinal dysfunction has also been associated with Alzheimer’s disease. This research focuses on the preparation of an electrochemical enzyme-based biosensor to monitor cholinergic signaling in the gut and its application for measuring electrically stimulated acetylcholine release in the mouse colon ex vivo. The biosensors were prepared by platinizing Pt microelectrodes through potential cycling in a potassium hexachloroplatinate (IV) solution to roughen the electrode surface and improve adhesion of the multienzyme film. These electrodes were then modified with a permselective poly(m-phenylenediamine) polymer film, which blocks electroactive interferents from reaching the underlying substrate while remaining permeable to small molecules like H2O2. A multienzyme film containing choline oxidase and acetylcholinesterase was then drop-cast on these modified electrodes. The sensor responds to acetylcholine and choline through the enzymatic production of H2O2, which is electrochemically oxidized to produce an increase in current with increasing acetylcholine or choline concentration. Important figures of merit include a sensitivity of 190 ± 10 mA mol−1 L cm−2, a limit of detection of 0.8 μmol L−1, and a batch reproducibility of 6.1% relative standard deviation at room temperature. These sensors were used to detect electrically stimulated acetylcholine release from mouse myenteric ganglia in the presence and absence of tetrodotoxin and neostigmine, an acetylcholinesterase inhibitor. 

The research experiences for undergraduates (REU) programGreg M. Swain, hailing from the Department of Chemistry at Michigan State University, examines cross-disciplinary training in sustainable chemistry and chemical processes, including the critical role of mentoring and finding research experiences for undergraduates. Sustainability is the practice of reducing the environmental impacts of human existence and conserving natural resources for future generations. Green chemistry is a part of the sustainability approach that encourages manufacturing processes and the design of products that minimize the use and generation of hazardous substances. Stated another way, sustainable chemistry and chemical processes should use resources, including energy and raw materials, “at a rate at which they can be replaced naturally, and the generation” of waste cannot be faster than the rate of their remediation, as Horváth IT points out. (1)