Location of molecules in layer-by-layer assembled microcapsules influences activity, cell delivery and susceptibility to enzyme degradation

Multi-layer microcapsules: fresh insights and new applications

“…Using biodegradable polymers such as polyarginine or dextran sulfate in the fabrication of microcapsules permits degradation of the microcapsule structure. This process can be explored by working with microcapsules in isolation [13] but is also evident when microcapsules are introduced into live cells where enzymes within phagocytic structures access core contents [14]. In our studies, we have been able to monitor this process in cells through the use of plasmid DNA in the microcapsule core; we know this cargo must be liberated and access the nucleus before gene transcription can occur [13].…”

“…This process can be explored by working with microcapsules in isolation [13] but is also evident when microcapsules are introduced into live cells where enzymes within phagocytic structures access core contents [14]. In our studies, we have been able to monitor this process in cells through the use of plasmid DNA in the microcapsule core; we know this cargo must be liberated and access the nucleus before gene transcription can occur [13]. Plasmid DNA was also released when it formed an outer or sub-outer microcapsule layer, but when it was integrated into the structural layers of the microcapsule (a middle layer), no release (monitored via expressed luciferase enzyme) was observed.…”

“…Plasmid DNA was also released when it formed an outer or sub-outer microcapsule layer, but when it was integrated into the structural layers of the microcapsule (a middle layer), no release (monitored via expressed luciferase enzyme) was observed. In this middle layer location, it would seem that the plasmid DNA was subjected to degradation before its liberation [13]. If this so-called 'hidden' middle layer could be liberated in a way that retained biological activity, it could present a stealth approach for molecule delivery.…”

“…The extent of protection seems to differ in studies with isolated microcapsules [13] and when engulfed by cells where cargo molecules in the core are protected from degradation [14]. There are few alternative approaches that physically protect biological molecules, but it will be important to determine the biocompatibility of such synthetic structures.…”

Optical monitoring of adipose tissue destruction under encapsulated lipase action

“…Encapsulation of enzymes has been widely used, as it can help to avoid their structural changes allowing protection from the rigid external environment. Such method allows one to improve the reusability and stability of enzymes .…”