Branched Amphiphilic Peptide Capsule Uptake by Aspergillus Nidulans

The ability of branched amphipathic peptide capsules (BAPC) to encapsulate and transport payloads into cells offers new approaches to deliver active ingredients (AIs). Until now, we have found that the BAPC were completely inert in previously tested eukaryotic cells. However, photographs have been collected that demonstrate Aspergillus nidulans, a common soil fungus, demonstrates intracellular uptake and subsequently break down the BAPC nanoparticles releasing the encapsulated dye inside the fungal cells.

Figure 1. BAPC are broken down in Aspergillus nidulans, releasing encapsulated dye inside the fungal cell.

Experiments were designed to optimize delivery of fungicides to this fungal species. In follow-up experiments, it was observed that BAPC can encapsulate and deliver the fungicide thiourea. When spotted on an Aspergillus spread milk plate, the BAPC-encapsulated thiourea showed a clear zone of inhibition. Thiourea is present in the isolated media of liquid cultures after exposing the fungi to BAPCs containing the AI. This result indicates that not only are the BAPC being opened, but the fungi are able to secrete BAPC-degrading proteases. This also demonstrates that common soil fungus will degrade BAPC, indicating that they will not accumulate in the environment.