Simultaneous optical measurements of cell motility and growth

Shamira Sridharan,Mustafa Mir,Gabriel Popescu

doi:10.1364/boe.2.002815

Abstract

It has recently been shown that spatial light interference microscopy (SLIM) developed in our laboratory can be used to quantify the dry mass growth of single cells with femtogram sensitivity [M. Mir et al., Proc. Nat. Acad. Sci. 108, 32 (2011)]. Here we show that it is possible to measure the motility of single cells in conjunction with the dry mass measurements. Specifically the effect of poly-L-lysine substrate on the dry mass growth of Drosophila S2 cells is studied. By measuring the mean square displacement of single cells and clusters it is shown that cells that adhere better to the surface are unable to grow. Using such a technique it is possible to measure both growth and morphogenesis, two of the cornerstones of developmental biology.

Highlights

The fundamental processes of developmental biology are cell differentiation, cell growth, and morphogenesis [1]
It has recently been shown that spatial light interference microscopy (SLIM) developed in our laboratory can be used to quantify the dry mass growth of single cells with femtogram sensitivity [M
We show that it is possible to measure the motility of single cells in conjunction with the dry mass measurements

Summary

Introduction

The fundamental processes of developmental biology are cell differentiation, cell growth, and morphogenesis [1]. To achieve morphogenesis motility is crucial as it enables cells to position themselves in space and time before undergoing growth or differentiation [2]. It has been calculated that in order to answer the simple question of whether the cells are growing exponentially or linearly, a resolution of less than 6% in cell size is required [3]. This requirement translates into sub-picogram mass resolution and sub-micron in size. Additional constraints to these measurements are due to the fact that cells are highly motile and morphologically dynamic

Methods

Results

Conclusion