Papain grafted into the silica coated iron-based magnetic nanoparticles ‘IONPs@SiO2-PPN’ as a new delivery vehicle to the HeLa cells

Abstract

The present study aims at engineering, fabrication, characterization, and qualifications of papain (PPN) conjugated SiO2-coated iron oxide nanoparticles ‘IONPs@SiO2-PPN’. Initially fabricated iron oxide nanoparticles (IONPs) were coated with silica (SiO2) using sol–gel method to hinder the aggregation and to enhance biocompatibility. Next, PPN was loaded as an anticancer agent into the silica coated IONPs (IONPs@SiO2) for the delivery of papain to the HeLa cancer cells. This fabricated silica-coated based magnetic nanoparticle is introduced as a new physiologically-compatible and stable drug delivery vehicle for delivering of PPN to the HeLa cancer cell line. The IONPs@SiO2-PPN were characterized using FT-IR, AAS, FESEM, XRD, DLS, and VSM equipment. Silica was amended on the surface of iron oxide nanoparticles (IONPs, γ-Fe2O3) to modify its biocompatibility and stability. The solvent evaporation method was used to activate PPN vectorization. The following tests were performed to highlight the compatibility of our proposed delivery vehicle: in vitro toxicity assay, in vivo acute systemic toxicity test, and the histology examination. The results demonstrated that IONPs@SiO2-PPN successfully reduced the IC50 values compared with the native PPN. Also, the structural alternations of HeLa cells exposed to IONPs@SiO2-PPN exhibited higher typical hallmarks of apoptosis compared to the cells treated with the native PPN. The in vivo acute toxicity test indicated no clinical signs of distress/discomfort or weight loss in Balb/C mice a week after the intravenous injection of IONPs@SiO2 (10 mg kg−1). Besides, the tissues architectures were not affected and the pathological inflammatory alternations detection failed. In conclusion, IONPs@SiO2-PPN can be chosen as a potent candidate for further medical applications in the future, for instance as a drug delivery vehicle or hyperthermia agent.