Dynamically Visualized Mechano-Responsive Supramolecular Self-Assembly System for Small Molecule Release.

The mechano-responsiverelease of small molecules has received extensive attention in ultrasound (US)-controlled drug release in recent years because it can achieve non-invasive, spatiotemporally controlled precise drug release. However, the vast majority of small molecules mechano-release reported so far are based on polymer systems, which suffer from complex preparations and single mechano-response. Here, an isoguanosine (isoG) visualized mechano-responsive supramolecular self-assembly (isoG-VMRSS) system was successfully constructed by a one-pot reaction. It is completely composed of small molecules, which allows for multiple mechano-responsive releases of isoG (at least 9 times) and ultimately has potential for application in US drug release. A combined experimental-computational approach reveals the supramolecular network structure (formed by the joint action of related metal coordination bonds, boronate ester bonds and hydrogen bonds mediated by isoG) gradually formed inside the system is the underlying internal mechanism. Therefore, it provides a new and effective idea of small molecule release in the field of mechanochemistry.