(474g) Virus-Based Platform for Intracellular Biosensing

Macromolecules, such as aptamers, have been used extensively for the detection and therapy of diseases. However, the usefulness of these nanoscale biosensors is often limited by difficulties in cellular entry, endosomal escape into the cytoplasm and reaching specific subcellular compartments. Viruses have specifically evolved to penetrate cells and respond to physiological cues, and are therefore attractive platforms that can be utilized to overcome the aforementioned challenges. In the present study, we attempted to engineer adeno-associated virus (AAV), a non-pathogenic mammalian parvovirus, into a biosensor. We explored the feasibility of inserting exogenous functional peptides into signal responsive regions of the AAV capsid to generate novel outputs upon detection of preset signals. We show that a small functional peptide can be inserted into the N-terminus of a viral capsid subunit and it is only externalized when the virus is stimulated. Our results demonstrate the first proof-of-concept in exploiting AAVs N-terminus externalization mechanism for reprogramming the virus into an intracellular biosensor. Through the development of a virus-based biosensor, we expect to overcome intracellular delivery obstacles faced by other probes, thereby facilitating the investigation and therapy of pathological processes at the cellular level.