Fig 1.
Schematic of stamping method for fragmenting surface-adsorbed.
A PDMS stamp in the form of a grating is ‘inked’ with DNase I cutting enzyme and is brought into contact with a surface on which DNA molecules have been deposited. The substrate is a polished silicon wafer coated with a 70nm PMMA film.
Fig 2.
Apparatus for dip-coating (‘combing’) DNA molecules onto a substrate by withdrawal from solution.
Fig 3.
(A) AFM topographical image of a silicon grating used as a master mold for making silicone elastomer stamps. (B) Height cross-section along the white line in (A).
Fig 4.
Optical micrograph of a cross-section of a soft lithographic grating.
Fig 5.
End-on and side views of a silicone grating with appended fluid reservoir.
The grating is placed in contact with the substrate containing the surface-adsorbed DNA and the DNase I enzyme and BSA surface coating are applied through the reservoir.
Fig 6.
Fluorescence image of SyBr Gold labeled DNA.
Upper left area was covered with a solution containing 0.095U/μl of DNase I in NEB DNase I Reaction Buffer and shows effective digestion of DNA in that region.
Fig 7.
Fluorescence image of fragmented DNA remaining after digestion by DNase I diffusing through microfluidic channels.
Distance from reservoir inlet is 1.1mm.
Fig 8.
Measured diffusion distance of FITC-labeled BSA through micorfluidic channels versus (diffusion time) 1/2.
Fig 9.
DNA (at high density) fragmented on a surface by DNase I.
Distance from inlet is 8.7mm.