Stretching and selective immobilization of DNA in SU-8 micro- and nanochannels

Abstract

Nanoimprint lithography is used to fabricate 200nm–10μm wide SU-8 channels reversal imprinted onto Si substrates. The immobilization and stretching of double stranded λ-DNA molecules within the micro- and nanochannels are demonstrated and controlled by varying the hydrophobicity of SU-8 using oxygen plasma exposure. Site-directed immobilization of DNA is achieved by the integration of 10μm wide SU-8 patterns with 6μm gaps into 100μm wide and 1μm deep Si channels.

DNA combing on low-pressure oxygen plasma modified polysilsesquioxane substrates for single-molecule studies

“…Surface potential change measured using KPFM is hence attributed to the prolonged DNA immobilization on PSQ surface in LP plasma conditions, with some initial assistance from crests and valleys on the surface (surface roughness). Though DNA immobilization and stretching have been demonstrated earlier using polymers like SU-8 and PDMS, 43,44 after subjecting to O 2 plasma treatment, none of these works come up with a clear mechanism to explain the phenomena as we are attempting here. Zeta potential measurements of O 2 plasma treated PSQ surfaces using buffer conditions in our experiments could further reveal information on the contribution of surface charges but would be a separate work on its own to compare the two (dry and wet) conditions.…”

Beyond Gel Electrophoresis: Microfluidic Separations, Fluorescence Burst Analysis, and DNA Stretching

“…One can also use a motor driven, droplet spreading tool on an APTES-treated glass surface, 555 drag a micropipette tip across the surface 556 or incline the glass slide to produce a gravitational flow. 557 Other methods of fixation include DNA adsorption to hydrophobic SU-8 in nanochannels 558 and investigations of molecular combing of oligonucleotides. 559 …”

Fabrication of fluidic chips with 1-D nanochannels on PMMA substrates by photoresist-free UV-lithography and UV-assisted low-temperature bonding

“…For example, proteins can be enriched up to million folds via the electrokinetic concentration polarization occurred on nanofluidic filters (Wang et al 2005;Wu and Steckl 2009;Kim et al 2006). DNAs can be stretched when they are transported through nano-scale conduits (Yang et al 2007; Krishnan et al 2007). Furthermore, without using a gel matrix, DNAs can be separated with a nanofluidic device containing entropic traps (Han and Craighead 2000;Cabodi et al 2002) or with nanocapillaries .…”