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Advanced graphene nanodevices with functional hydrogels for DNA sequencing

Periodic Reporting for period 1 - GRAPHNANOGEL (Advanced graphene nanodevices with functional hydrogels for DNA sequencing)

Reporting period: 2018-09-01 to 2020-08-31

Real time reading of individual nucleotides in a DNA molecule using a graphene nanopore has been significantly hampered from two aspects: one is the very fast translocation speed of single DNA molecules, and the other is the extremely high low frequency noise. The aim of this project is to develop a versatile (chemical) route inspired from DNA gel electrophoresis to i) significantly reduce the speed of DNA translocation through a nanopore, and ii) to reduce any possible mechanical vibrations of the free-standing graphene membrane, to reach a good signal to noise ratio (SNR) and hence a low error rate conducing to DNA sequencing applications.
We fabricated positively charged functional polyacrylamide hydrogel by copolymerization of acrylamide-containing amines and sole acrylamides. Such hydrogel can have high affinity with negatively charged DNA and later we combine this chemistry with a graphene nano platform. That is, we successfully fabricated a graphene nanopore supported on a glass micropore inside hydrogel using pulsed voltage fabrication method, which suggests a new avenue for realizing cost-efficient, high-performance graphene nanodevices. With such a glass micropore supported graphene-hydrogel system, we found that the low frequency noise of the graphene nanopore inside hydrogel is much lower than the one that without hydrogel. DNA translocation experiments performed on this electrical pulse fabricated graphene-on-glass (GOG) nanopore, demonstrated the suitability of the GOG nanopore for single molecule measurements. Strikingly, compared to previously reported translocation time on ssDNA in solid state nanopores, the results on hydrogel functionalized GOG nanopores indicate deceleration of DNA translocation as much as one order of magnitude.
During the fellowship, I joined a chemical biology and electrical physics environment with my polymer chemistry and physics back-ground. I learnt knowledge that are complementary to my current backgrounds. Such experiences will put me on track for a tenured scientist by combining both fields. I am also very pleased that the host group is very friendly and active. I am involved in many cutting-edge research activities and established many new collaborations and connections. During the period of fellowship, I also cosupervised PhD students and bachelor students’ LO2 training, gave presentations on conferences (e.g. Dutch Polymer Days) and visited and collaborated with many groups in other Universities.
Along with the help of my interdisciplinary networks, this project help to enable the widespread application of graphene-based nanopore biosensors for ultra-sensitive in vitro diagnostics. Companies which my host supervisor also has contacted with) and deal with the strict regulatory issues that exist in the health care system. The research can therefore foster the European economic competitiveness and the global economic performance. In the long term, the main societal impact is the low-cost graphene-based nanopore biosensors with ultrahigh sensitivities will pave the way towards a radically changed healthcare scenario, where DNA/protein sequencing will enable to tailor personnel medicine and treatments on genetic/proteomic maps of the individual patients.