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This is [Version unknown!] version of a paper presented at the 21th International Conference on Miniaturized Systems for Chemistry and Life Sciences (Micro TAS), The Chemical and Biological Microsystems Society.
Citation for the original published paper:
Guo, M., Hernández-Neuta, I., Madaboosi, N., Nilsson, M., van der Wijngaart, W.
(2017)
CROSS-MEMBRANE ELECTRICAL DETECTION OF DNA.
In: Academic Publishing International
N.B. When citing this work, cite the original published paper.
Permanent link to this version:
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-219945
CROSS-MEMBRANE ELECTRICAL DETECTION OF DNA M. Guo1, I. Hernández-Neuta
2, N. Madaboosi
2, M. Nilsson
2, and W. van der Wijngaart
1
1
KTH Royal Institute of Technology, Department of Micro and Nanosystems, Sweden;
2
Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Sweden
ABSTRACT
We introduce out-of-plane metallic nanowire formation on DNA templates, which are stretched through a porous membrane by applying a receding meniscus interface. We demonstrate the direct electrical detection of DNA using these gold nanowire bridges between the membrane’s opposite surfaces. Such a simple electrical read- out can be extended for biosensor applications, thanks to the high specificity and multiplexing offered by Rolling Circle Amplification (RCA).
INTRODUCTION
DNA stretching to form DNA nanowires on planar structures, such as glass slides [1], PDMS [2], or SU8 pil- lars [3], has previously been reported. This concept is promising for building molecular nanobridges that are use- ful in the electrical activation of DNA templates, for the construction of DNA–based nanocircuitry [4]. The poor electrical properties of DNA [5-6] can be overcome by creating metal nanowires, where the DNA acts as template for the seed-mediated growth of silver [7], gold [8-10], or palladium [11,12] wires. Most previous methods that build metal nanowires used DNA fixation to flat surfaces, followed by metal enhancement to create fixated con- ductive nanowires [7,8,10-12]; another study used a microwave process for nanowire synthesis in bulk solution [12], later extended by Russell et al. [10] for electrical biosensing of DNA, however, with only limited efficiency and sensitivity.
Here, we utilize specific padlock probes (PLPs) and RCA to synthesize long ssDNA concatemers (Rolling Circle Products-RCPs) on a gold-modified porous membrane (Fig. 1). Thereafter, the RCPs are stretched by forced convection through the membrane pores, followed by gold enhancement chemistry to convert the stretched DNA into gold nanowires (AuNWs). These out-of-plane AuNWs are detected by direct electrical measurement of the resistance between the membrane’s surface electrodes.
RESULTS
We successfully generated cross-membrane gold wires. The cross-membrane electrical resistance value was measured and noticed to drop from an open circuit resistance (prior to gold enhancement) to below 20 Ohm (=
setup Limit of Detection ) after enhancement from 10 min to 55 min, for all positive assays. Control measurements where one of the assay steps was omitted, e.g. zero PLP concentration, no stretching by convection, or omitting gold chemistry steps, resulted in no detectable RCP stretching, as characterized by optical measurements including SEM and Confocal Laser Scanning Microscopy (CLSM).
CONCLUSION
The advantages of the demonstrated system including technical simplicity and assay efficiency, combined to- gether with the high signal-to-noise ratio, makes it appealing for multiplexed point-of-care sensing of biomole- cules in diverse fields such as clinical (e.g., for infectious diseases and cancer diagnostics), military and environ- mental monitoring settings. The formation of out-of-plane AuNWs based on the porous membrane geometry is promising to improve the detection of low-abundant DNA and promote the bio-compatibility with nanocircuit systems, thank to the generation of the stretched DNA. Commendable molecular specificity arising from PLPs and enhanced sensitivity due to the assay design allow for a large dynamic range for measurement of both nucleic acids and proteins (when combined with proximity ligation assay), thus extending the flexibility of the system for precise biomolecule sensing.
ACKNOWLEDGEMENTS
We acknowledge the support from European Union’s Horizon 2020 research and innovation programe ND4ID under the Marie Sklodowska-Curie grant agreement No. 675412. We also acknowledge the Swedish Re-
search Council (VR) and Swedish Foundation for Strategic Research (SSF) grant (Flu-ID project No. SBE13- 0125). MG acknowledges the financial support from the China Scholarship Council in China. We also express our gratitude to Cecilia Aronsson for the help with the sample preparation.
Figure 1:Schematic illustration of synthesis of gold nanowires from stretched RCPs, coated with complementary Au-seed particle oligonucleotides between the porous polymer membrane surfaces
REFERENCES
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[2] B. Charlot1 et al. Biomicrofluidics, 2014, 8, 014103.
[3] Miele E et.al. Small, 2015, Jan 7;11(1):134-40.
[4] Stoltenberg et al. Biomedical Microdevices, 2004, Vol.6, Issue 2, 105-111.
[5] A.J. Storm et al. APPL. Phys. Lett, 2001, 79,3881-3883.
[6] K. Welch et al., Nanotechnology, 2011, 22, 125707.
[7] E. Braun et al., Nature, 1998, 391, 775-778.
[8] E. Braun et al., Adv. in Physics, 2004, 53, 441-496.
[9] S. Kundu et al., Langmuir, 2008, 24, 9668-9674.
[10] C. Russell et al., ACS Nano, 2014, 8, 1147-1153.
[11] K. Nguyen et al., Adv. Mat., 2008, 20, 1099-1104.
[12] J. Richter et al., Nanoscale, 2000, 94, 8720.
CONTACT
* Wouter van der Wijngaart ; phone: +46-733-254021; wouter@kth.se
