title: 'Living cantilever arrays' for characterization of mass of single live cells in fluids.
abstract: The size of a cell is a fundamental physiological property and is closely regulated by various environmental and genetic factors. Optical or confocal microscopy can be used to measure the dimensions of adherent cells, and Coulter counter or flow cytometry (forward scattering light intensity) can be used to estimate the volume of single cells in a flow. Although these methods could be used to obtain the mass of single live cells, no method suitable for directly measuring the mass of single adherent cells without detaching them from the surface is currently available. We report the design, fabrication, and testing of 'living cantilever arrays', an approach to measure the mass of single adherent live cells in fluid using silicon cantilever mass sensor. HeLa cells were injected into microfluidic channels with a linear array of functionalized silicon cantilevers and the cells were subsequently captured on the cantilevers with positive dielectrophoresis. The captured cells were then cultured on the cantilevers in a microfluidic environment and the resonant frequencies of the cantilevers were measured. The mass of a single HeLa cell was extracted from the resonance frequency shift of the cantilever and was found to be close to the mass value calculated from the cell density from the literature and the cell volume obtained from confocal microscopy. This approach can provide a new method for mass measurement of a single adherent cell in its physiological condition in a non-invasive manner, as well as optical observations of the same cell. We believe this technology would be very valuable for single cell time-course studies of adherent live cells.
authors.affiliation: Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Kidong
authors.initials: K
authors.lastname: Park
authors.forename: Jaesung
authors.initials: J
authors.lastname: Jang
authors.forename: Daniel
authors.initials: D
authors.lastname: Irimia
authors.forename: Jennifer
authors.initials: J
authors.lastname: Sturgis
authors.forename: James
authors.initials: J
authors.lastname: Lee
authors.forename: J Paul
authors.initials: JP
authors.lastname: Robinson
authors.forename: Mehmet
authors.initials: M
authors.lastname: Toner
authors.forename: Rashid
authors.initials: R
authors.lastname: Bashir
mesh_terms: D018929:Cell Culture Techniques; D048429:Cell Size; D002470:Cell Survival; D006367:HeLa Cells; D006801:Humans; D044085:Microfluidics / Q000379:methods*; D018613:Microscopy, Confocal; D055095:Optics and Photonics; D012825:Silicon / Q000737:chemistry*; D013997:Time Factors
chemical_list: D012825:Silicon