Observation of DNA Molecules Using Fluorescence Microscopy and Atomic Force Microscopy

Abstract

This article describes experiments for an undergraduate instrumental analysis laboratory that aim to observe individual double-stranded DNA (dsDNA) molecules using fluorescence microscopy and atomic force microscopy (AFM). dsDNA molecules are observed under several different conditions to discuss their chemical and physical properties. In particular, immobilization of dsDNA molecules on a planar substrate in their stretched form permits students to measure the size of the dsDNA molecules using these microscopic techniques. Comparison between the measured size and literature values provides a means for teaching the characteristics of the microscopic techniques. The experiments can be completed within four hours and are suitable to introduce these modern microscopic methods as well as the basics of nanotechnology to undergraduate students during limited lab hours.