Solid state dna sizing by atomic force microscopy

Sizing DNA molecules is our of the most widely used analytiial approaches in molecular biology and biochemistry. Although several alternate approaches have been proposed, most of DNA sizing is performed by gel elect rophoresi-,. Alotnic force microscopy (AKM) allows rapid, accurate and reproducible visialization ol DNA molecules adsorbed onto solid substrate. Mere we propose a solid state DNA si/ing method based on ATM. Substrates suitable for rapid and easy immobilization of DNA, and subsequent ATM imaging have been developed. DNA images are subjected to automatic length determination us ing pattern-recognition software. At present when processing a single sample, sample preparation, AKM imaging and analysis takes l-ri-2U minutes. However, we experte that the average sizing time will eventually be less than 60 seconds. Currently solid st ate DNA sizing yields results comparable to agarose gel elect rophoresis for many types of samples. Decoration of DNA fragments by inactive restriction enzymes or other sequence specific binding/modifications should provide important information in addition to the size.