First steps towards simultaneous isolation and detection of exosomes with carbon nanotube-based SMRs

Exosomes are small (20-150nm) intercellular vesicles carrying valuable information regarding disease presence or evolution. Their isolation from body fluids is one of the most challenging targets. Although many techniques already exist, these are still inefficient, expensive and time-consuming. One of these new methods is nanofiltration. Within this technique, carbon nanotube (CNT) forests have been proposed as good candidates owing to their easily controllable tube separation and growth. Previous works have proven the isolation of different particles; however, optical read-out methods are still needed to confirm the success of the process. Here we propose and start studying the integration of CNT forests in solidly mounted resonators to simultaneously isolate exosomes and gravimetrically estimate the trapped amount. As a first step we prove the ability of our devices to trap and detect CD63 antibodies, due to their high affinity to exosomes. We demonstrate a frequency shift of around 280±8 kHz with an antibody concentration of 8 nM, four times lower than previously reported concentrations used for the detection of antibodies with thin film acoustic resonators, for similar frequency shifts