Reactive Oxygen Species‐Regulating Polymersome as an Antiviral Agent against Influenza Virus

Reactive oxygen species (ROS) produced during mitochondrial oxidative phosphorylation play an important role as signal messengers in the immune system and also regulate signal transduction. ROS production, initiated as a consequence of microbial invasion, if generated at high levels, induces activation of the MEK (mitogen‐activated protein kinase kinase)/ERK (extracellular signal‐regulated kinase) pathway to promote cell survival and proliferation. However, viruses hijack the host cells' pathways, causing biphasic activation of the MEK/ERK cascade. Thus, regulation of ROS leads to concomitant inhibition of virus replication. In the present study, poly(aniline‐co‐pyrrole) polymerized nanoregulators (PASomes) to regulate intracellular ROS levels are synthesized, exploiting their oxidizing‐reducing characteristics. Poly(aniline‐co‐pyrrole) embedded within an amphiphilic methoxy polyethylene glycol‐block‐polyphenylalanine copolymer (mPEG‐b‐pPhe) are used. It is demonstrated that the PASomes are water soluble, biocompatible, and could control ROS levels successfully in vitro, inhibiting viral replication and cell death. Furthermore, the effects of homopolymerized nanoregulators (polypyrrole assembled with mPEG‐b‐pPhe or polyaniline assembled with mPEG‐b‐pPhe) are compared with those of the PASomes. Consequently, it is confirmed that the PASomes can regulate intracellular ROS levels successfully and suppress viral infection, thereby increasing the cell survival rate.