Tese: Controlled release of the inner content of gellan gum microcapsules using temperature as the trigger mechanism
Aluno(a) : Mateus Aguiar Rodrigues de LimaOrientador(a): Márcio Carvalho
Área de Concentração: Termociências
Data: 24/06/2022
Link para tese/dissertação: https://doi.org/10.17771/PUCRio.acad.60094
Resumo: Microcapsules are commonly used as vehicles for on-demand delivery of active contents. The capsule protects the internal content from interference of the external environment and deliver it in a controlled manner. In addition to being widely used in the pharmaceutical, food and cosmetic industries, microcapsules can be also a viable solution in medicine and in the petroleum industry to replicate themselves as cells in the body or optimize oil recovery, respectively. However, the use of a microcapsule implies the use of a shell that, due to the urge for sustainability, needs more than ever to be a biodegradable substance. In this work, we present a method of controlled release of actives protected by a biodegradable gellan-based microcapsule using temperature as the trigger for its destruction. The study shows the effect of physical properties of the capsules in the delivery time of their internal content and how the release behaves with the increase of the heat rate involved in the process. Microcapsules were produced with flow-focusing microfluidic devices with diameters varying between 190 and 510 um while the shell thicknesses varied between 4 and 50 um. The study shows that, in addition to the size, the shell material influences the release behavior. In addition, another important point is how the gellan gum nature affects the thermal trigger event, since the results show that when gellan is in its deacylated form (low-acyl) it is more resistant to changes, but when its natural form (high-acyl) is added to the chain, it becomes more sensitive to the trigger mechanism until a thickness-diameter ratio threshold, where the degradation behavior changes and the delivery is delayed.