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Developing an engineerable chemical reaction that is triggerable for simultaneous chemical bond formation and cleavage by external cues offers tunability and orthogonality which is highly desired in many biological and materials applications. Here, we present a chemical switch that concurrently captures these features in response to chemically and biologically abundant and important cues, viz. , thiols and amines. This thiol/amine-triggerable chemical switch is based on a Triggerable Michael Acceptor (TMAc) which bears good leaving groups at its β-position. The acceptor undergoes a “trigger-to-release” process where thiol/amine addition triggers cascaded release of leaving groups and generates a less activated acceptor. The newly generated TMAc can be further reversed to liberate the original thiol/amine by a second nucleophile trigger through a “trigger-to-reverse” process. Within the small molecular volume of the switch, we have shown five locations that can be engineered to achieve tunable “trigger-to-release” kinetics and tailored reversibility. The potential of the engineerable bonding/debonding capability of the chemical switch is demonstrated by applications in cysteine-selective and reversible protein modification, universal self-immolative linkers, and orthogonally addressable hydrogels. 

Abstract The development of nanoparticle‐based biomedical applications has been hampered due to undesired off‐target effects. Herein, we outline a cellular AND gate to enhance uptake selectivity, in which a nanoassembly–cell interaction is turned on, only in the concurrent presence of two different protein functions, an enzymatic reaction (alkaline phosphatase, ALP) and a ligand–protein (carbonic anhydrase IX, CA IX) binding event. Selective uptake of nanoassemblies was observed in cells that overexpress both of these proteins (unicellular AND gate). Interestingly, selective uptake can also be achieved in CA IX overexpressed cells, when cocultured with ALP overexpressed cells, where the nanoassembly presumably acts as a mediator for cell–cell communication (bicellular AND gate). This logic‐gated cellular uptake could find use in applications such as tumor imaging or theranostics. 

Abstract We report a new molecular design strategy that allows for the propagation of surface enzymatic events inside a supramolecular assembly for accelerated molecular release. The approach addresses a key shortcoming encountered with many of the currently available enzyme‐induced disassembly strategies, which rely on the unimer–aggregate equilibria of amphiphilic assemblies. The enzymatic response of the host to predictably tune the kinetics of guest‐molecule release can be programmed by controlling substrate accessibility through electrostatic complexation with a complementary polymer. Accelerated guest release in response to the enzyme is shown to be accomplished by a cooperative mechanism of enzyme‐triggered supramolecular host disassembly and host reorganization.