Selective probing of mRNA expression levels within a living cell

Abstract

We report on a selective and nondestructive measurement of mRNA (messenger ribonucleic acid) expression levels within a living cell. We first modify an atomic force microscope tip to create a tapered nanoscale coaxial cable. Application of an ac (alternating potential) between the inner and outer electrodes of this cable creates a dielectrophoretic force attracting mRNA molecules toward the tip-end which is pretreated with gene specific primers. We selectively extracted and analyzed both high ( ∼ 2500 ) and extremely low ( 1 1 ¯ 0 ) copy number mRNA from a living cell mRNA in less than 10 s.