Enzyme-Based Synthetic Protein Nanoparticles as Colloidal Antioxidants

Protein-based drug delivery systems have gained popularity due to their biocompatibility, straightforward surface modification, and potential for intrinsic therapeutic activity. Among therapeutic proteins, enzymes are particularly attractive because of their specificity, efficient reaction rates, regeneration after substrate turnover, and proven track record in the treatment of diseases ranging from cancer to inherited metabolic and lysosomal storage disorders. Herein, previous work on electrohydrodynamic jetting is expanded upon by developing a novel class of protein nanoparticles that features therapeutic enzymes. In particular, nanoparticles incorporating the antioxidant enzyme, catalase, at weight fractions as high as 50% are reported. Catalase-based synthetic protein nanoparticles (CAT-SPNPs) demonstrate sustained antioxidative activity, retain significantly enhanced enzymatic activity compared to its solute form, and overall demonstrate good structural stability. Moreover, surface functionalization of CAT-SPNPs with targeting antibodies results in ≈12.5-fold increase in uptake over unmodified control particles. Importantly, CAT-SPNPs exert protection from oxidative stress, as indicated by significant increase in viability and reduction in LDH release compared to equivalent amounts of free catalase. Taken together, the work establishes targeted enzyme-based SPNPs as a platform for enhancing the drug-like properties of therapeutic enzymes.