Nanofluidic and Nanophotonic Study of Biomolecular Interactions

• Applicant: Siddharth Ghosh, Ph.D.
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Biophysics
• Term: from 2018 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 405479535

The current biochemical assays available in diagnostic laboratories are not sensitive to single molecules, which is crucial for detecting early biomolecular interactions responsible for neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, prion diseases, and amyotrophic lateral sclerosis. There are two primary problems behind the limited sensitivity. First is the diffusion or random walk of molecules in fluid, and second is tagging/labelling the molecules of interest with an efficient and stable fluorescent dye for optical detection. We propose an integrated single molecule handling device or chip to circumvent these problems by transporting single molecules one by one and detecting them using more than one on-chip graphene detectors without employing any fluorescent labels (label-free). The device will contain fluidic channels of diameters in the order of molecules’ size (i.e., couple of nanometres (nm) – 100,000 times smaller than the diameter of a human hair) – nanochannel; to avoid diffusion induced escape of single molecules from the detection volume. The nanochannels will be integrated with nm wide graphene nanoribbons (mono-atomic layered thick crystalline sheets of carbon atoms, they have exceptional size dependent optical and electronic properties) which will be optically excited and recorded electronically. The discrete transits of single molecules through nanochannels will interrupt the electronic excited states of the graphene due to weak coupling. The recorded interruptions from more than one adjacent nanoribbons will be correlated to determine the biomolecular interactions at single-molecule level in a controlled nanofluidic environment by analysing the diffusion coefficient and fluid flow of biomolecules.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Tuomas Knowles, Ph.D.