Formation of Peptide-Pyrazole Nanoassemblies and Their Biological Applications

Abstract

Over the past decade, peptide-based biomaterials has garnered remarkable momentum due to their wide range of applications. In this work, the di-peptide Gly-Ser was conjugated with 4-Amino-1-methyl-3-n-propyl-5-pyrazolecarboxamide (AMP) to form a building block for developing a new family of nanoassemblies. By incorporating a pyrazole moiety with GlySer, the nanoassemblies can integrate the extensive biological properties of both these moieties. The formed conjugate was self-assembled at varying pH values in order to promote formation of higher order supramolecular structures. Our results indicated that the morphologies formed were found to be pH dependent. While nanofibrillar assemblies were formed under acidic conditions, a mix of vesicles and fibers were observed under neutral to basic conditions. In order for the assemblies to be applicable as potential therapeutic biomaterials, we assessed the interactions of the assemblies with mouse MC3T3-E1 cells in vitro using fluorescence microscopy. The results indicated that interactions of the assemblies with the cells were dependent on the morphologies of the assemblies. In general, cells were well-spread and continued to proliferate. Further distinct actin stress fibers were evident, indicating cell-motility. We also conducted anti-microbial studies against the fungus Rhizopus Arhizus (Rhizopus) and the bacteria Escherichia Coli (E-Coli) as well as Staphylococcus Aureus (SA). Overall all assemblies showed inhibition of fungal growth, while only nanofibrillar assemblies which were formed under acidic conditions showed significant inhibition toward bacterial growth, indicating the importance of the nanoassembly morphology in bacteriostatic analysis. Thus, we have developed a new family of nanoassemblies with potential therapeutic applications for antimicrobials or for building scaffolds for tissue regeneration.