Instrument: Suspended Microchannel Resonator

A high-precision instrument for measuring single-cell mass, volume, and density using one or two resonators connected by a serpentine fluidic channel. During operation of the dual SMR, a dilute cell population suspended in cell media, Fluid 1, is delivered to the sample bypass via pressure-driven flow (Figure 2A, Supplementary Figure 1), and single cells flow into the first SMR (SMR1) for the first buoyant mass measurement. The cells then travel through a microchannel to a cross-junction, where a second fluid of different density is introduced. After the cross-junction, cells continue through a long serpentine channel, which facilitates mixing of the two fluids. The cells next enter a second cantilever (SMR2) for a buoyant mass measurement in the mixed fluid, Fluid 2. As cells flow through each cantilever, a change in resonance frequency is recorded (Figure 2B), which is determined by each cell's buoyant mass in each cantilever's corresponding fluid.

Reference: Bryan, A.K. et al. (2015) Measuring single cell mass, volume, and density with dual suspended microchannel resonators. Proc Natl Acad Sci USA 108: 10992–10996 doi:10.1073/pnas.1104651108. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3895367/