Antimicrobial peptides (AMPs) have emerged as a promising alternative to traditional antibiotics, particularly in light of multi-antibiotic resistant strains of bacteria. Histone derived AMPs (HDAPs) are an integral part of this toolset, with multiple mechanisms of action, strong antimicrobial effects, and protein design potential. Our lab has previously designed two robust antimicrobial peptides: DesHDAP1 and the subsequent DesHDAP1-C, which has an additional cysteine residue to facilitate conjugation to other molecules for fluorescence imaging or attachment to active moieties. Previous work demonstrated that the cysteine mutation did not alter antibacterial activity of the DesHDAP1 peptide. However, it is also critical to determine whether this change affects potential toxicity against eukaryotic cells. Using dye-based assays, we quantified cellular metabolism of human embryonic kidney cells as a proxy for cell viability. By optimizing this process and the data analysis, I was able to compare cytotoxicity of the two designed peptides to that of conventional antibiotics. This approach can be applied to other designed peptides, providing a blueprint for future toxicity studies on eukaryotic cells.
