High-throughput measurement of mass at the attogram scale for nanoparticles in solution using Suspended Nanochannel Resonators

In this Master’s Degree Thesis work I present the technological improvements of the Suspended Nanochannel Resonator (SNR) buoyant mass sensor technology developed in collaboration between the Manalis lab at the Koch Institute for Cancer Research – MIT and the CEA/Leti research center in Grenoble, France. 100nm thick piezoresistive gauges have been embedded in the hollow cantilevers of the SNR devices to allow a fully electrical piezoresistive readout mechanism of the beam’s resonance frequency. This achievement made it possible to design arrays of SNR sensors that are fluidically connected either in series or in parallel to perform different functions. Here, I compare the piezoresistive readout mechanism to the previously used optical lever scheme showing that they have equivalent performances: the optimized design of the piezoresistive gauge element has no negative impact on the SNR noise and a limit of detection in the attogram order of magnitude can be achieved. Then, I describe the parallel SNR array technology and the way I characterized its performances and compared them to the well-established single-resonator SNR. The results show an order of magnitude improvement in the measurement throughput of nanoparticles with buoyant mass down to 10 ag, in aqueous solutions at concentrations as low as 10^8 particles/mL; polydisperse samples of particles with different sizes and mass can be measured using this technology and less than 20 nm resolution in size difference can be achieved for gold nanoparticles. The simultaneous implementation of piezoresistive gauges for electrical readout and of parallel SNR arrays effectively lowers the measurement time for this technology making it competitive with other established techniques for mass sensing in solution: future industrial applications are envisioned.