Fmoc-Dipeptide/Porphyrin Molar Ratio Dictates Energy Transfer Efficiency in Nanostructures Produced by Biocatalytic Co-Assembly

Abstract

The controlled self-assembly of porphyrin derivatives (TCPP, tetrakis(4-carboxyphenyl)porphyrin) within Fmoc-protected (Fmoc=9-Fluorenylmethyloxycarbonyl) dipeptide (Fmoc-TL-NH₂ ) nanofibers is demonstrated. The biocatalytic co-assembly in aqueous medium generated an energy transfer hydrogel. Depending on the concentrations of porphyrin used, the resulting nanofibrous gels show two distinct regions of self-assembly behavior that is, integration of TCPP into nanostructures to produce two-component co-assembly fibers, or heterogeneous self-aggregation of TCPP within the self-assembled matrix observed at higher concentrations. The mode of assembly directly impacts on the energy transfer efficiency of these nanostructures. These results show that reversible biocatalytic co-assembly of structural and functional components enables fine-tuning of peptide/porphyrin energy transfer nanostructures.

Keywords: aromatic peptide amphiphiles; biocatalytic self-assembly; energy transfer; porphyrin; supramolecular hydrogels.