10 April 2024 | Lei Chen, Robert Nixon & Guillaume De Bo
The article presents a novel approach to force-controlled release of small molecules using a rotaxane actuator. Rotaxanes, interlocked molecules with a macrocycle trapped on a stoppered axle, are used as actuators to trigger the release of cargo molecules. The study demonstrates that up to five cargo molecules can be released per rotaxane actuator, achieving release efficiencies of up to 71% in solution and 30% in bulk. The rotaxane actuator is designed with a pillar[5]arene macrocycle and a poly(methyl acrylate) chain, allowing for mechanical activation through two polymer chains attached to the axle and macrocycle. The release mechanism involves the sequential activation of Diels–Alder adducts, leading to the release of cargo molecules via mechanochemical scission. The versatility of the rotaxane actuator is demonstrated by releasing functional molecules such as a drug, a fluorescent tag, and an organocatalyst. The study also explores the activation of multicargo rotaxanes in solution and bulk, showing that the rotaxane actuator can release up to five cargo molecules in bulk with a release efficiency of up to 30%. This work paves the way for more sophisticated force-controlled release systems in various applications, including drug delivery and materials science.The article presents a novel approach to force-controlled release of small molecules using a rotaxane actuator. Rotaxanes, interlocked molecules with a macrocycle trapped on a stoppered axle, are used as actuators to trigger the release of cargo molecules. The study demonstrates that up to five cargo molecules can be released per rotaxane actuator, achieving release efficiencies of up to 71% in solution and 30% in bulk. The rotaxane actuator is designed with a pillar[5]arene macrocycle and a poly(methyl acrylate) chain, allowing for mechanical activation through two polymer chains attached to the axle and macrocycle. The release mechanism involves the sequential activation of Diels–Alder adducts, leading to the release of cargo molecules via mechanochemical scission. The versatility of the rotaxane actuator is demonstrated by releasing functional molecules such as a drug, a fluorescent tag, and an organocatalyst. The study also explores the activation of multicargo rotaxanes in solution and bulk, showing that the rotaxane actuator can release up to five cargo molecules in bulk with a release efficiency of up to 30%. This work paves the way for more sophisticated force-controlled release systems in various applications, including drug delivery and materials science.