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Ultra-high density three dimentional DNA arrays for biosensing

Periodic Reporting for period 1 - NanoPorous DNA-array (Ultra-high density three dimentional DNA arrays for biosensing)

Reporting period: 2016-09-01 to 2018-08-31

Biosensors are now among essential equipment and facilities in hospitals and health-care centers. Early diagnosis can save lives and therefore there is a great need for sensitive sensors that can detect minor amount of molecular markers in a body fluid. Nanosensors are among the most promising devices for such requirement.
In the context of nanobiosensors it is important to achieve a method in which precise modification of the nanosensor is possible. This is a great challenge in the field of nanotechnology and it is not easy to produce nanomaterials with high precision. As at nanoscale the size of the material has a significant effect on its properties, it is necessary to precisely control the dimension of the nanomaterial for biosensing applications. In a series of work we aimed to introduce a method that can be used for precise manipulation of nanomterials which have potential applications is biosensing. We used helium ion microscope to reduce the pore size of a nanoporous membrane with a resolution of less than 1 nm. With the results of this successful study we made an overall objective to implement the new technique to combine nanofluidics and atomic force microscopy for localized detection of biomolecules.
We used helium ion microscope to reduce the pore size of a nanoporous membrane with a resolution of less than 1 nm (DOI: 10.1038/s41467-018-03316-7 , Open Access).
The same method was applied to produce extremely thin nanowires with high precision and control over the dimensions (DOI: 10.1002/pssr.201700333 , Open Access).
Both nanoporous membranes and nanowires studied, are of great interest as biosensing platform. Therefore it is expected that the reported results will make a big impact in the field, enabling the researchers to further investigate and optimize the introduced method for more practical application.
Moreover, we used the same technique to produce nanoholes (< 10 nm in size with <1 nm resolution) on top of a cantilever which is then mounted on an Atomic Force Microscope (AFM). The probe acts as a nanopore sensors and it allows localized detection of ions and biomolecules. For example, the force feedback of the AFM enables precise localization of the cantilever inside of a living cell or a tissue. The nanopore sensors records translocation of the biomolecules which appear as a transient jump in the current signal. The shape and the length of the transient signal provides information regarding the type and length of the translocating molecules. This platform is used for molecular level sensing inside and outside of a live cell and the new technology is called scanning nanopore microscope. (the results of this work will be published in the future)
In a parallel study, we characterized the physical properties of the scanning nanopore microscope and found out its potentials and limitations in studying nano-structured surfaces. This detailed study shows that the size and shape of the fabricated pores are of great importance in the functionality of the device (the results will be published online in Journal of Applied Physics 2018).
The introduced nanopore platform with its high sensitivity can be implemented to overcome the current limitations in biomolecular detection in biofluids. Moreover, it can be used for delivery of molecules to the cells and tissues which can have an impact for drug discovery research.