DNA bridges: A novel platform for single-molecule sequencing and other DNA-protein interaction applications

Microfluidic delivery of cutting enzymes for fragmentation of surface-adsorbed DNA molecules

We describe a method for fragmenting, in-situ, surface-adsorbed and immobilized DNAs on polymethylmethacrylate(PMMA)-coated silicon substrates using microfluidic delivery of the cutting enzyme DNase I. Soft lithography is used to produce silicone elastomer (Sylgard 184) gratings which form microfluidic channels for delivery of the enzyme. Bovine serum albumin (BSA) is used to reduce DNase I adsorption to the walls of the microchannels and enable diffusion of the cutting enzyme to a distance of 10mm. Due to the DNAs being immobilized, the fragment order is maintained on the surface. Possible methods of preserving the order for application to sequencing are discussed.

Molecular combing and its application in clinical settings

Molecular combing technology (MCT) is an effective means for stretching DNA molecules and making them thus accessible for in situ studies. MCT uses the force exerted in the process of liquid flow via surface tension to stretch DNA molecules and spread them on solid surfaces, i.e. glass cover slips. Many DNA molecules can be stretched at the same time in parallel and neatly arranged side-by-side, making the approach convenient for statistical analysis. Accordingly, DNA replication and transcription can be studied at the single molecule level. In this paper, the principle, experimental methods, important applications, advantages and shortcuts of MCT in medical field are presented and discussed.