Layer-by-Layer Fabrication of Polyelectrolyte Microcapsules: A Laboratory Experiment on Polymeric Self-Assembly, Microencapsulation, and the Underlying Chemistry

A laboratory experiment was developed to introduce the concept of polymeric self-assembly to the students via an interactive practical experience. Here, it is demonstrated how oppositely charged polymers can self-assemble layer by layer to build polymeric microcapsules and how this process can be used to encapsulate cargo molecules. The as-synthesized microcapsules were characterized by optical microscope, and bovine serum albumin protein is used as a model cargo system to study the encapsulation efficiency of the microcapsules through UV–visible absorption spectroscopy. This experiment enables the students to understand the chemistry behind electrostatic self-assembly and its application in hollow capsule formation, which has been extensively explored as a delivery vehicle in biomedical applications. The spherical hollow microcapsules are noteworthy because of their propensity to incorporate and protect the cargo molecules in their inner cavities. This experiment is especially appropriate for an interdisciplinary elective course as it connects concepts and techniques from chemistry, materials science, analytical spectroscopy, and biomedical applications.