Triggered Release from Polymer Capsules

TLDR

Stimuli‑responsive capsules are employed in drug delivery, fragrance release, food preservation, and self‑healing, and their contents can be released by chemical, biological, light, thermal, magnetic, or electrical stimuli. The study aims to highlight chemical‑reaction‑based mechanisms for controlled release from solid polymeric shells and to present encapsulation, triggering methods, and related challenges. The authors describe encapsulation techniques, triggering approaches, and the covalent‑bond‑cleavage mechanisms in polymer shells that drive cargo release. They conclude that chemically induced activation faces significant obstacles that limit its practical use for controlled release.

Abstract

Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.