SICM-Based Nanodelivery System for Local TRPV1 Stimulation

There is a general need to conduct single cell analysis at the nanoscale to further understand fundamental cellular processes. Within the pain research field, one interesting question that remains unanswered is whether TRPV1 channels present an organised distribution in the membrane of sensory neurons and whether it is altered during the establishment of a sensitised state. The main objective of this work was to develop a quantitative capsaicin dosing system to locally stimulate TRPV1 channels at the membrane surface of nociceptors. Local dosing was achieved by using nanopipettes as channels for the delivery, and voltage as the driving force. To achieve a quantitative delivery an accurate control of the nanopipette-cell distance is needed, for what the Scanning Ion Conductance Microscopy (SICM) positioning technology was utilised. Analytical expressions to precisely describe the distribution of molecules outside a nanopipette were obtained and compared to computational simulations. After that, the nanodosing system was successfully employed to deliver the TRPV1 agonist capsaicin to the cell body of sensory neurons. Finally, an automated multipoint delivery system was developed to assess TRPV1 response after delivery to different points at fine structures such as the dendrites.