Surface functional DNA density control by programmable molecular defects

Abstract

Programmable surface-patterned functional DNA density is achieved via manipulation of molecular-level defects through chemical lift-off lithography. Artificial SAM defects are well-tunable by a contact-induced reaction, enabling molecular environment guidance and DNA insertion to be spatially and quantitatively addressable. This straightforward molecular density control creates an advanced avenue toward fabricating multiplexed bioactive substrates.

A Special Connection between Nanofabrication and Analytical Devices: Chemical Lift-Off Lithography

“…As investigated by current-voltage curves, a SAMcovered Au surface can be well-tuned through contact induced reactions to produce gradually changing active species characteristic redox signals. 30 This observation points to a surface defects tunable environment accomplished by simple stampsubstrate sealing duration conditions, and implies a convenient approach for subsequent surface anchoring probe quantity control. Important parameters in this surface probe density manipulation are dependent on available defect sites in conjunction with the insertion procedure, i.e.…”

“…These so-called "artificial defects" are attributed to the Au-thiolate rupturing process in CLL, which are namely distinguished from "natural defects" in a SAM system. 30,31 The primary advantages of these artificial defects are their convenience to produce large area production, and well-tunable properties. In a practical operation, generation of these defects can be manipulated by stamp-SAM contact seal condition and functional matrix selection.…”

“…In a practical operation, generation of these defects can be manipulated by stamp-SAM contact seal condition and functional matrix selection. 18,29,30 For example, the ability of CLL to remove surfaceanchored molecules depends on the selective interaction between an activated PDMS surface and alkanethiol tail moieties of SAMs. Mixtures of liftable and non-liftable molecules can therefore result in a different ratio of available surface defects (Figure 3), where the steric effect of alkanethiol molecule tail groups also contributes to the interface reaction yield.…”

“…17 Taking thiolated DNA molecule functionalization as an example, these probes can be inserted into molecular defects in this matrix to give clear surface pattern boundaries while maintaining their functionalities. 29,30,34 Similarly, well-defined surface patterns can also be produced using aptamers, and most importantly, these anchored probes present a self-standing behavior which recognizes themselves as active probes for corresponding target recognition ( Figure 5). 31 A practical aptamer based sensor is therefore generated by this approach, where target recognition-induced aptamer three-dimensional geometry change triggers the move of aptamer tail-linked fluorophore and initiates the fluorescence quenching via nonradiative energy transfer through Au.…”

“…By changing aptamer sequences, this analytical platform can detect metal ions, organic molecules, and toxic drugs selectively, which is crucial in a practical sensor design. 18,30 Compared to colloidal type sensors, surface-based analytical devices benefit from their reusability, and repetitive signal responses lying on fluorescence on/off cycles can also be obtained on this platform. Besides, long-term storage of these sensing matrix encounters no obvious feature degradation and this active interface simultaneously maintains high capability toward target recognition.…”