A Modern Experiment for Old Concepts: A Supramolecular Transient System

Scientists have always been fascinated by transient far -from-equilibrium systems. Since the (early) 1970s, there have been literature reports on the implementation of didactic experiments as a tool for attracting and stimulating students' and general public interest. In this work, a group of 12 high school students, supported by their chemistry teacher, have developed a supramolecular system formed by gold nanoparticles functionalized with a positively charged thiol group. The positively charged nanoparticles were aggregated by adding polyanionic ATP as fuel. Aggregates were determined by UV-vis spectroscopy. Disaggregation was realized by adding an enzyme capable of hydrolyzing the ATP P-O bonds. The lifetime of the aggregates depends on the enzyme concentration and efficiency. Several aggregation-disaggregation cycles were performed. Students were divided into three groups, each of four students. Teachers assigned different duties to each group. The first group synthesized and purified the gold nanoparticles and the capping thiolic group. The second group determined UV-vis optical properties of the nanosystem and implemented the conditions for further experiments. The third group performed experiments to characterize the nanosystem and its lifetime. At the time of this activity, all of the students were attending their last year at chemistry high school in Italy. As didactic goals, they have been trained in problem solving, the use of advanced lab instruments, and following and projecting their own research activity.

Automated summary

This study presents the successful development of a supramolecular system formed by gold nanoparticles, functionalized with a positively charged thiol group, by a group of 12 high school students supported by their chemistry teacher. The system exhibited aggregation and disaggregation behaviors by adding polyanionic ATP as fuel and an enzyme capable of hydrolyzing ATP P-O bonds. The students were divided into three groups to complete different tasks, enhancing their problem-solving skills, advanced lab instrument usage, and research capabilities.