The synthesis, characterization, and application of peptide-capped magnetite nanoparticles for the targeting of cancer cells

In this study, a comparative analysis was performed upon three co-precipitation techniques for the synthesis of capped magnetite nanoparticles as to optimize the approach to the highest quality nanoparticles. Three techniques were applied whereby the capping agent either introduced before the stage of nanoparticle precipitation, simultaneously to the stage of precipitation, or after the stage of precipitation. The resultant nanoparticles were tested in terms of their size, dispersity, crystallinity, and magnetic characteristics. The three techniques gave nanoparticles of varying sizes and characteristics. Out of the three synthetic techniques, the post precipitation introduction method gave the highest quality nanoparticles in terms of size distribution, crystallinity and magnetic character. Three novel peptides were synthesized, incorporating amino acids to varying degrees. Structure was confirmed via IR and NMR spectroscopy. The peptides were studied potentiometrically to explore their acid nature and were explored computationally as to discern possible modes of interaction with the nanoparticles. These three peptides were further used in the capping of magnetite nanoparticles. For this set of nanoparticles, a higher synthesis temperature and larger iron content were used as to obtain larger nanoparticles. For the capping procedure, the post precipitation technique was used due to its previous positive results, once again yielding high quality nanoparticles with low size dispersity, high crystallinity, and high magnetic saturations. The nanoparticles were also seen to display positive zeta potentials, which are beneficial for cellular interactions. The peptides and peptide-capped nanoparticles were tested for biological activity against the healthy MCF-10A and cancerous MCF-7 cell lines. The MTT assay displayed increased proliferation for both the cell lines treated with the nanoparticles, while the peptide treatments decreased the MCF-10A cell lines proliferation and increased the MCF-7 proliferation. TEM analysis displayed nanoparticles in the cellular sections. An ICP-OES analysis on the cells showed that the capped nanoparticles of similar zeta potentials were seen to be taken up excessively by cells as compared to the uncapped. The nanoparticles of lower zeta potentials but higher L-glutamine content were taken up to a lesser degree