Carbodiimide-mediated immobilization of serratiopeptidase on amino-, carboxyl-functionalized magnetic nanoparticles and characterization for target delivery

A hybrid biomaterial of serratiopeptidase enzyme was prepared with magnetic nanoparticles (MNPs) via carboxyl and amino-functionalization and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) for direct immobilization. The average size of prepared MNPs was found to be 15.05 ± 3.06 nm. Attachment of amino and carboxyl groups was confirmed by Fourier transform infrared spectroscopy. X-ray diffraction confirmed the purity and phase integrity of Fe3O4. The MNPs and enzyme-loaded-MNPs (EMNPs) were of saturation magnetization 58 and 50 emu g−1, respectively. Thermogravimetric analysis of EDC-MNPs and EMNPs showed the presence of organic coating over MNPs. Serratiopeptidase immobilized on amino-functionalized magnetic nanoparticles showed loss of enzyme activity due to crosslinking of enzyme, while serratiopeptidase immobilized on carboxyl-functionalized magnetic nanoparticles was better and gave 115.78 mg protein g−1 MNPs, enzyme loading 168.32 U g−1 MNPs at optimized MNPs-to-enzyme ratio 1.0 mg mg−1. In vitro and in vivo studies showed that EMNPs with magnetic targeting is more effective in drug permeation and reduction in edema than free enzyme.