Partial sequencing of a single DNA molecule by a scanning tunnelling microscope (CAT#: STEM-MIT-0323-LJX)

Introduction

The scanning tunnelling microscope is capable of the real-space imaging and spectroscopy of molecules on an atomic scale. Numerous attempts have been made to use the scanning tunnelling microscope to sequence single DNA molecules, but difficulties in preparing samples of long-chain DNA molecules on surfaces, and problems in reproducing results have limited these experiments. Single-molecule DNA sequencing service with a scanning tunnelling microscope is provided by using an oblique pulse-injection method to deposit the molecules onto a copper surface. First, we show that guanine bases have a distinct electronic state that allows them to be distinguished from the other nucleic acid bases. Then, by comparing data on M13mp18, a single-stranded phage DNA, with a known base sequence, the 'electronic fingerprint' of guanine bases in the DNA molecule is identified. It is possible to sequence individual guanine bases in real long-chain DNA molecules with high-resolution scanning tunnelling microscope imaging and spectroscopy.