Figure 3. Optimization of nanocarriers structure for catalase delivery in macrophages.

Nanozymes consisting of catalase and a negatively charged block copolymer demonstrate low toxicity, high loading capacity and release from BMM, however provide limited protection of the enzyme against protease degradation inside the cell-carriers. Nanozymes based on positively charged block copolymers, especially the PLs, showed increased cytotoxicity and low loading and release rates, but were highly protective of catalase. Furthermore, nanozymes with PEG corona show good stability in water, limited cytoxicity and efficient protection of catalase, but decreased loading capacity and cell release. The optimal nanozyme formulation is one based on positively charged block copolymers (PEI-PEG/catalase and PL-PEG/catalase). Used with permission ²⁹.