Synthesis of carbon-based fluorescent polymers driven by catalytically active magnetic bioconjugates

Bioconjugates based on a redox protein and iron oxide magnetic nanoparticles were employed in the catalytic polymerization of ortho-, meta-and para-substituted phenylenediamines at room temperature for the synthesis of carbon-based fluorescent polymers. UV-Vis absorption measurements of the three obtained products showed a red shift compared to the starting materials. These results together with the FT-IR and XPS analyses confirm the successful formation of the polymers. In particular, the component quantification in the C 1s XPS spectra revealed the high proportion of C-N bonds, associated with the oxidative polymerization of the precursors. MALDI-TOF MS analysis was performed in order to determine the molecular weights of the products. The synthesized poly-oPDA, poly-mPDA and poly-pPDA resulted to have a highly green, blue and red fluorescence, respectively. The reusability of the biocatalyst and the effect of the pH were investigated in the reaction for the ortho isomer. The biocatalytic system showed optimum results when the pH was below the enzyme isoelectric point (pI).