Piper nigrum Extract-mediated Synthesis of Fe₃O₄ Nanoparticles and Their Conjugation with Nimotuzumab

The present study reports the preparation of Fe₃O₄ NPs uses the green synthesis method of Piper nigrum extract which has a high alkaloid content as the source of weak base. Surface functionalization of Fe₃O₄ NPs was performed using SH-PEG-NHS coating to conjugate nimotuzumab. The obtained NPs were characterized by Fourier-transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD). The results of the phytochemical test showed that the Piper nigrum extract contains polyphenolic compounds, alkaloids, and terpenoids. XRD analysis exhibited that the formed Fe₃O₄ NPs crystals were in 14.53 nm size according to the American Mineralogist Crystal Structure Database (AMCSD) number 96-900-5841 (magnetite). Surface modification with SH-PEG-NHS and further conjugated with nimotuzumab was observed on the FTIR results which showed a loss of NHS and SH functional groups of PEG. In conclusion, based on the results, the nimotuzumab-conjugated Fe₃O₄ NPs have been successfully prepared via PEG modification.