Label-Free Impedimetric Immunosensor for Nerve Growth Factor Protein Constructed Using an Automated Dispensing System

We describe the development, validation and optimisation of label‐free immunosensors for Nerve Growth Factor (NGF) protein. Screen‐printed carbon electrodes were electrochemically coated with polyaniline, and onto this antibodies to NGF were immobilised using electrostatic or neutravidin‐biotin interactions. These were constructed manually or using an automated liquid dispensing system. QCM demonstrated deposition of individual layer stages and binding of NGF. Studies revealed clear increases in immunosensor impedance following antigen exposure. Automated methodologies produced sensors with lowered sample‐to‐sample variation. Affinity produced electrodes offered higher sensitivities than those produced utilising electrostatic interactions. NGF between 25–1000 pg mL−1 could be determined using the optimised sensor.