Antimicrobial Peptides and the Potential in Hygiene Products

Abstract: Antimicrobial peptides (AMPs) are essential components of the defence system spanning virtually every kingdom of life. The peptides are relatively small, amphipathicmolecules of variable length, sequence, charge and structure. AMPs have been shown to possess activity against a wide range of microorganisms, including bacteria and fungi, and kill their targets by multiple mechanisms mostly through membrane disruption. The field of AMPs has lately received an increased attention, much due to the serious issue of resistance development of microorganism strains against current antibiotics. However, because of the extensive range of microorganism related problems, the field of AMPs is also of interest in other areas such as hygiene applications, which is the main focus of this thesis. The use of AMPs in hygiene products could prevent common pathogen related problems involved in hygiene. Conditions such as fungal and bacterial infections are related to diapers and panty liners, also it is of importance to keep skin and surfaces hygienic. The suggested AMP applications in hygiene products are, AMPexpressing probiotics, AMPs in various materials and substances that induce the body’s production of AMPs. The main purpose of this thesis is to provide an understanding of the field of antimicrobial peptides and to evaluate the potential in hygiene applications. Both a practical and theoretical approach was applied for this purpose. The theoretical part included an extensive literature study as well as interviews with active scientists and companies. Besides the possibilities of AMPs, there are several challenges involved such as specificity, resistance, cost and stability. However, it should be noted that there are AMPs in commercial products such as pharmaceuticals, foodpreservatives and wipes, suggesting a possibility for use in hygiene products. The practical part of the thesis involved the testing of Nisin A, Lactoferricin B, Magainin 2, Buforin II and Histatin-5 to evaluate their antimicrobial activity against three relevant pathogens: Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial activity was measured by an agar diffusion assay named inhibition zone assay. It was examined how the antimicrobial activity varied between microorganisms, different concentrations of sodium chloride and also between different strains. From the practical results it could be concluded that with the right conditions, most of the peptides showed activity depending on the microorganisms. It was also demonstratedthat many peptides are salt sensitive, and finally, when tested against different strains of the same microorganism the peptides did not show much difference in activity. To sum up, there is a potential for AMPs in hygiene products but many challenges needs to be considered.