{"id":5762,"date":"2012-07-18T22:27:43","date_gmt":"2012-07-18T22:27:43","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2012\/?p=5762"},"modified":"2012-07-18T22:27:43","modified_gmt":"2012-07-18T22:27:43","slug":"measuring-single-cell-density","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2012\/measuring-single-cell-density\/","title":{"rendered":"Measuring Single-cell Density"},"content":{"rendered":"

We have used a microfluidic mass sensor to measure the density of single living cells. By weighing each cell in two fluids of different densities (see Figure 1), our technique measures the single-cell mass, volume, and density of approximately 500 cells per hour with a density precision of 0.001 g mL\u22121<\/sup>. We observe that the intrinsic cell-to-cell variation in density is nearly 100-fold smaller than the mass or volume variation.\u00a0 As a result, we can measure changes in cell density indicative of cellular processes that would be otherwise undetectable by mass or volume measurements. Here, we demonstrate this with four examples: identifying erythrocytes infected with Plasmodium falciparum malaria in a culture, distinguishing transfused blood cells from a patient\u2019<\/em>s own blood (as in Figure 2), identifying irreversibly sickled cells in a sickle cell patient, and identifying leukemia cells in the early stages of responding to a drug treatment. These demonstrations suggest that the ability to measure single-cell density will provide valuable insights into cell state for a wide range of biological processes.<\/p>\n\n\t\t