Molecular gels have been studied for over 160 years and are now used in diverse applications such as regenerative medicine, drug-delivery, biosensing, and environmental remediation. Despite their utility, many applications rely on a narrow set of gelator structures because there is no adequate model to guide their invention. The challenge in designing new gelators is that many factors can influence their self-assembly, such as pH, ionic strength, temperature, solvent identity, concentration, and molecular structure. Our proposal addresses this challenge by developing a new strategy to design molecules for stimuli-induced gelations. The central theme is that the stimulus promotes self-assembly by enhancing the attractive intermolecular interactions (in contrast to the traditional focus on stimuli-induced changes in solubility). In our preliminary results we descrive the first successful de novo design where gel formation is triggered by an oxidation-induced planarization and aided by donor-acceptor interactions. We demonstrate that this stimuli-responsive material can be used to sense nitric oxide, an important biomarker for pulmonary inflammation. Our future research goals are three-fold: (1) Test the generality of this strategy by designing new stimuli-responsive molecules for other stimuli. (2) Develop methods for signal amplification using functionalized polymers. (3) Evaluate techniques for remote monitoring of gelation using acoustic wave-based measurements. Given the diverse applications that already utilize molecular gels, the results of these studies should have a broad impact across several disciplines. including medicine, engineering, and materials science.
Arnold O. Beckman exemplifies the meaning of the word humanitarian. Combined with his unwavering enthusiasm for life, his keen sense of humor and his strong moral and ethical principles, he is a national icon.