Measurement of the volume growth rate of single budding yeast with the MOSFET-based microfluidic Coulter counter

Abstract

We report on measurements of the volume growth rate of ten individual budding yeast cells using a recently developed MOSFET-based microfluidic Coulter counter. The MOSFET-based microfluidic Coulter counter is very sensitive, provides signals that are immune from the baseline drift, and can work with cell culture media of complex composition. These desirable features allow us to directly measure the volume growth rate of single cells of Saccharomyces cerevisiae LYH3865 strain budding yeast in YNB culture media over a whole cell cycle. Results indicate that all budding yeast follow a sigmoid volume growth profile with reduced growth rates at the initial stage before the bud emerges and the final stage after the daughter gets mature. Analysis of the data indicates that even though all piecewise linear, Gomperitz, and Hill’s function models can fit the global growth profile equally well, the data strongly support local exponential growth phenomenon. Accurate volume growth measurements are important for applications in systems biology where quantitative parameters are required for modeling and simulation.

A microfluidic tubing method and its application for controlled synthesis of polymeric nanoparticles

“…Microfluidic channels are fabricated using standard soft-lithography techniques with an SU8 master mold on a silicon substrate. 4 The microfluidic chip for leakage tests has a straight channel which is 50 μm wide (or 300 μm wide), 50 μm deep, and 6 cm long (Fig. 1a).…”

Using the fringing electric field in microfluidic volume sensors to enhance sensitivity and accuracy

“…Events shown in B and C are for particles suspended in a 21% glycerol solution, making them practically neutrally buoyant. The 21% glycerol solution has a density of 1.065 g/cm 3 , which only slightly differs from that of the microspheres (1.062 g/cm 3 ). This small difference in densities is sufficient to cause a slight settling along the vertical axis in the timeframe of the experiment.…”

“…Each buffer contained 0.1% bovine serum albumin (BSA), 0.1 M KCl, and varying concentrations of glycerol (0%, 21%, or 42%). Carrier fluid densities were quantified with a suspended microchannel resonator (SMR): 10 1.004 6 0.001 g/cm 3 , 1.065 6 0.001 g/cm 3 , and 1.121 6 0.001 g/cm 3 for 0%, 21%, and 42% glycerol solutions, respectively. To prevent beads from non-specifically interacting with microchannel surfaces, 0.1% g/ml of detergent (Contrex, Decon Labs Inc.) was added prior to experimentation to both the water and glycerol heavy solutions.…”

Quantifying the volume of single cells continuously using a microfluidic pressure-driven trap with media exchange

“…Time-lapse fluorescence microscopy can provide valuable information as to the cell cycle progression of individual cells, 5 but 2D optics requires geometric assumptions, and, thus, can provide an incomplete picture of growth. 6,7 Microfluidic lab-on-chip devices with integrated sensors can provide high-resolution growth tracking of individual cells, either through mass, volume, or density monitoring. 4,7,8 Recently, a microfluidic mass sensor was used to track the buoyant mass of individual cells using a suspended microchannel resonator (SMR).…”

“…6,7 Microfluidic lab-on-chip devices with integrated sensors can provide high-resolution growth tracking of individual cells, either through mass, volume, or density monitoring. 4,7,8 Recently, a microfluidic mass sensor was used to track the buoyant mass of individual cells using a suspended microchannel resonator (SMR). 4,9 Monitoring growth can also be accomplished by tracking volume using microfluidic volume sensors 7 operating on the Coulter principle.…”