Functionalized silica shell magnetic nanoparticles for nanophase peptide synthesis applications

A new nanostructured solid phase synthesis magnetic support consisting of core-shell type magnetic nano particles based on magnetite, para-aminobenzoic acid (PABA) and secondary silica shell were synthesized by coprecipitation method and characterized. An newly designed organic linker with an ending hydroxyl group inspired by HMBA linker (4-hydroxy methyl benzamide) widely employed in classical peptide solid phase synthesis was obtained from 1,4-dimethylolbenzene and gamma-isocyanatopropyltriethoxysilane and was grafted on the surface in order to be used for the nanophase synthesis of peptides. Three reaction stages, yielding a tripeptide sequence, using n-terminal protected amino acids and the principle of solid phase synthesis through the Fmoc strategy were performed, in order to prove the effectiveness of the nanophase peptide synthesis. The MS analysis confirmed the success of the tripeptide synthesis, recommending the new nanostructured system as a solid support in the solid phase synthesis of peptides. The intermediate and final materials were analysed by advanced characterization methods (SEM, TEM, BET, X-ray diffraction, magnetic properties, DLS, FT-IR, NMR for organic intermediates characterization, TGA and LC-MS).