title: Suspended microchannel resonators with piezoresistive sensors.
abstract: Precision frequency detection has enabled the suspended microchannel resonator (SMR) to weigh single living cells, single nanoparticles, and adsorbed protein layers in fluid. To date, the SMR resonance frequency has been determined optically, which requires the use of an external laser and photodiode and cannot be easily arrayed for multiplexed measurements. Here we demonstrate the first electronic detection of SMR resonance frequency by fabricating piezoresistive sensors using ion implantation into single crystal silicon resonators. To validate the piezoresistive SMR, buoyant mass histograms of budding yeast cells and a mixture of 1.6, 2.0, 2.5, and 3.0 µm diameter polystyrene beads are measured. For SMRs designed to weigh micron-sized particles and cells, the mass resolution achieved with piezoresistive detection (∼3.4 fg in a 1 kHz bandwidth) is comparable to what can be achieved by the conventional optical-lever detector. Eliminating the need for expensive and delicate optical components will enable new uses for the SMR in both multiplexed and field deployable applications.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: R
authors.initials: R
authors.lastname: Chunara
authors.forename: W
authors.initials: W
authors.lastname: Shen
authors.forename: K
authors.initials: K
authors.lastname: Payer
authors.forename: K
authors.initials: K
authors.lastname: Babcock
authors.forename: T P
authors.initials: TP
authors.lastname: Burg
authors.forename: S R
authors.initials: SR
authors.lastname: Manalis
mesh_terms: D017097:Electric Impedance; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008863:Microspheres; D008970:Molecular Weight; D015203:Reproducibility of Results; D004718:Saccharomycetales / Q000737:chemistry; D013696:Temperature