Stefan Salentinig1

1, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, , Switzerland

The design of new biomaterials for the targeted delivery of poorly water-soluble antimicrobial peptides that are sensitive to degradation is a major challenge in the biomedical field. In this context, antimicrobial peptides are gaining increasing attention as promising alternatives to conventional antibiotics in the light of the global emergence of antibiotic resistance. This presentation demonstrates the structural engineering of functional nanocarriers for antimicrobial peptides. These nanocarriers arise from the self-assembly of structure-forming biomolecules including amphiphilic lipids and nanocellulose. The comprehensive design of these functional nanomaterials requires an in-depth understanding of their structural and morphological characteristics. Small angle X-ray and neutron scattering (SAXS, SANS), dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo-TEM) showed that the antimicrobial peptides actively and critically integrate into the self-assembled nanocarriers, where they contribute to alterations in the structural features. For instance, certain antimicrobial peptides together with the amphiphilic lipids glycerol monooleate and oleic acid self-assemble to bicontinuous cubic structures, hexagonal- and sponge phases in water, depending on the composition and pH.[1,2] The pH-induced phase transitions in this system can be applied to release the peptide on demand for targeted delivery to bacteria infected locations in the body. These pH-responsive lipid structures mimic the highly ordered nanostructures that were discovered to form in situ during milk digestion, where they function as carriers for essential, poorly water soluble food components in the digestive tract, securing human survival.[3,4,5] Briefly, this presentation sheds light on the formation and transformation of functional bio-nanostructures with the aim of designing biomimetic delivery systems for antimicrobial peptides as alternative to conventional antibiotics.
1. Gontsarik M., Buhmann M., Yaghmur A., Ren Q., Maniura W., Salentinig S. J. Phys. Chem. Lett. 2016, 7, 3482–3486.
2. Gontsarik M., Mohammadtaheri M., Yaghmur A., Salentinig S. Biomaterials Science 2018, accepted, DOI: 10.1039/C7BM00929A.
3. Salentinig S., Phan S., Khan J., Hawley A., Boyd B. ACS Nano, 2013, 23, 10904-10911.
4. Salentinig S., Phan S., Hawley A., Boyd B. Angew. Chem. Int. Ed., 2015, 5, 1600-1603.
5. Salentinig S., Amenitsch H., Yaghmur A., ACS Omega, 2017, 2, 1441–1446.