Synthesis of Fe₃O₄-Chlorophyllin Nanoparticles for Preventing Amyloid Formation by Human Calcitonin

Abstract

The accumulation of amyloid fibrils is crucial in the development of amyloidosis. In addition, some hormone peptides, such as human calcitonin (hCT), have limited therapeutic potential owing to a high tendency of amyloid formation. Nowadays, nanotechnology offers many advantages in various scientific fields and can overcome some of the limitations in the development of traditional therapeutics. In the present study, we applied iron and copper chlorophyllin in the synthesis of ironoxide nanoparticles to obtain porphyrin derivative-coated nanoparticles, namely, Fe 3 O 4 -Chl/Fe and Fe 3 O 4 -Chl/Cu, respectively. We observed that the two nanoparticles, especially Fe 3 O 4 -Chl/Fe, stabilized hCT and influenced hCT aggregation. To further confirm the applicability of Fe 3 O 4 -Chl/Fe, we utilized another benzothiazole-based fluorescent probe to monitor hCT amyloid formation. Several biophysical techniques, including transmission electron microscopy, dynamic light scattering, and isothermal titration calorimetry, were also implemented in our examinations. The fibrillar content of hCT after co-incubation was further determined using Bis-ANS and Nile red assays. The remaining soluble monomeric or oligomeric content of hCT was assessed by gel electrophoresis and biological assays. We believed that our findings would assist in the development of hCT drug formulation. Application of Fe 3 O 4 -Chl/Fe can increase the stability and bioactivity of hCT.