Antioxidant Functionalized Polymer Capsules to Prevent Oxidative Stress

Polymeric capsules exhibit significant potential for therapeutic applications as microreactors, where the bio-chemical reactions of interest are efficiently performed in a spatial and time defined manner due to the encapsulation of an active biomolecule (e.g., enzyme) and control over the transfer of reagents and products through the capsular membrane. In this work, catalase loaded polymer capsules functionalized with an external layer of tannic acid (TA) are fabricated via a layer-by-layer approach using calcium carbonate as a sacrificial template. The capsules functionalised with TA exhibit a higher scavenging capacity for hydrogen peroxide and hydroxyl radicals, suggesting that the external layer of TA shows intrinsic antioxidant properties, and represents a valid strategy to increase the overall antioxidant potential of the developed capsules. Additionally, the hydrogen peroxide scavenging capacity of the capsules is enhanced in the presence of the encapsulated catalase. The capsules prevent oxidative stress in an in vitro inflammation model of degenerative disc disease. Moreover, the expression of matrix metalloproteinase-3 (MMP-3), and disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS-5), which represents the major proteolytic enzymes in intervertebral disc, are attenuated in the presence of the polymer capsules. This platform technology exhibits potential to reduce oxidative stress, a key modulator in the pathology of a broad range of inflammatory diseases.