Faezeh Tajik

As a graduate student in bioengineering, I am passionate about developing new early cancer detection tools. Currently, I am working on a project focused on developing nanoscale devices for fluorescence detection of small DNA molecules to build a nanoscale single-molecule sequencing platform. Within this project, we are paving the way for single-molecule DNA sequencing using the XToF methods (ToF; i.e., electrophoretic mobility). X-ToF chip consists of a network of nanofluidic channels that has the ability to considerably decrease sequencing cost and library preparation time, and significantly improve call accuracy.

In our lab, XToF is fabricated by milling nanochannels on the surface of Si masters with a focused ion beam (FIB), then transferring the pattern from the Si master to a low Tg, low-cost thermoplastic (COP, COC, etc.)

We are developing an innovative Single-Molecule Sequencing (SMS) strategy that consists of enzymatically cleaving intact DNAs using a processive enzyme to generate individual deoxyribonucleotide monophosphates (dNMPs). Within the network of XToF, a solid-phase bioreactor will be placed where λ-Exo is covalently immobilized for processively cleaving λ-DNA. Following the clipping of DNA, the detection of single deoxyribonucleotide monophosphates (dNMPs) will be achieved by electrokinetically shuttling cleaved bases through a nanochannel containing two in-plane nanopores. Then the sequencing reaction will be performed in two steps using a two-channel TIA empowered by automated voltage control across the input/output nanochannels.

My proposed SMS approach addresses the limitations of moderate base call accuracy associated with current nanopore sequencing.