Stimulus-responsive drug delivery systems generally aim to release the active pharmaceutical ingredient (API) in response to specific conditions and have recently been explored for disease treatments. These approaches can also be extended to molecular imaging to report on disease diagnosis and management. The stimuli used for activation are based on differences between the environment of the diseased or targeted sites, and normal tissues. Endogenous stimuli include pH, redox reactions, enzymatic activity, temperature and others. Exogenous site-specific stimuli include the use of magnetic fields, light, ultrasound and others. These endogenous or exogenous stimuli lead to structural changes or cleavage of the cargo carrier, leading to release of the API. A wide variety of stimulus-responsive systems have been developed—responsive to both a single stimulus or multiple stimuli—and represent a theranostic tool for disease treatment. In this review, stimuli commonly used in the development of theranostic nanoplatforms are enumerated. An emphasis on chemical structure and property relationships is provided, aiming to focus on insights for the design of stimulus-responsive delivery systems. Several examples of theranostic applications of these stimulus-responsive nanomedicines are discussed.

Edible, surfactant‐stripped, frozen micelles are formed from pheophytin (demetallated chlorophyll), a pigment that is naturally consumed in human diets. Pheophytin nanoparticles pass completely and safely through the gastrointestinal tract and enable trimodal gut contrast imaging via photoacoustic, fluorescence, and positron emission tomography techniques.

In order to co‐immobilize multiple enzymes, a wide range of nanomaterials has been designed to achieve synergistic enzyme activity and enhance catalytic efficiency. Nanomaterials, as carriers for enzyme co‐immobilization, possess various advantages such as tunable morphology and size, high specific surface area, and abundant chemically active sites. They can significantly enhance enzyme stability, activity, and catalytic efficiency. We overview the commonly used methods and strategies of enzyme co‐immobilization. This review further summarizes the latest research advances in nanomaterials for enzyme co‐immobilization applications over the past 5 years. Meanwhile, the advantages and challenges of these nanomaterials used for enzyme co‐immobilization as well as some potential future directions are also discussed.