Title: "Fabrication and Characterization of Thin Film Nanomaterials based Biosensing Devices for Assigning dynamic behavior of mammalian cells"
Summary: Cell-based biosensors (CBBs) are endowed with certain advantages compared to molecule-based approaches such as non-invasive long-term recordings, label-free detection, reduced response time, etc. CBBs have the ability to use the living cells directly, and hence, the biochemical effect of the direct spatial contact of living cells is converted into quantitative electrical signals by sensors or transducers, bridging the gap between electronics and biology. The signal comes to the transducer due to various phenomena of the cell, such as a change in ion transportation, metabolic pathway, membrane potential, barrier resistance, and morphology of the cells. In vitro cell-surface interaction is influenced by the substrate’s physicochemical and structural properties. The adherent cell establishes an active communication with the extracellular microenvironment via the membrane proteins; resulting in the formation of a cellular monolayer on the surface of an artificial substrate. Therefore, it is essential to understand the physicochemical and topographical properties of the choice of nanomaterial interested in interfacing with the adherent cells. Moreover, it was also desirous to use biocompatible, electrochemically, and thermally stable material with other characteristics such as reliability, accuracy, selectivity (or specificity), response time, and sensitivity, while considering material for the signal transduction purpose. Therefore, we investigated the functional behaviour of myoblast (C2C12) cells using a co-planar silver metal electrode system integrated to a low-cost ECIS system. Typically, the silver metal was thermally coated on the conventional glass substrate to construct a metal-insulator-metal (MIM) structure via the shadow mask method, to achieve an active layer’s dimensions of 1.5 mm wide and 4 mm length. At the same time, we developed a low-cost ECIS system using the electronic components available at the laboratory to construct a low-cost impedance measuring circuitry and calibrated the developed circuit, against the standard commercial resistor. Further, the MIM device was integrated to the developed impedance measuring circuitry to study the phenotypic change of adherent mammalian cells under the influence of an applied electric field, this was published in Journal of Analytical Science and technology (10.1186/s40543-020-00223-9). Then, we investigated the effect induced by cellular functional behaviour on the characteristic electrical properties of the e-beam deposited aluminum oxide (Al₂O₃) thin-film nanomaterial-based metal-insulator-metal (MIM) device. To fabricate the MIM device, Al₂O₃ thin film of ∼100 nm thickness was deposited on ITO electrode system and used as the active sensing interface. The fabricated MIM device was used as a platform to study the phenotypic change of adherent mammalian cells under the influence of an applied electric field, this was published in IEEE Transactions on NanoBioscience Journal (10.1109/TNB.2021.3068318). We also investigated the effect induced by cellular functional behaviour on the characteristic electrical properties of the sol-gel synthesized spin-coated zinc oxide (ZnO) thin film nanomaterial-based metal-semiconductor-metal (MSM) device. To fabricate the MSM device, ZnO thin film of ∼100 nm thickness was deposited on ITO electrode system and used as the active sensing interface. The MSM device was used as a platform to study the phenotypic change of adherent mammalian cells under the influence of the applied electric field, this work was published in IEEE Sensors Journal (10.1109/JSEN.2020.2990919). We also fabricated a larger area heterojunction device, ZnO thin film of ∼200 nm thickness was deposited p-type Si substrate, and to create ohmic contact, the aluminum metal electrode was used on both p-Si and n-ZnO. While ZnO was used as the active sensing interface. The fabricated heterojunction device was functionalized with poly-L-lysine and characterized for assessing the cell-induced electrical characteristic property change, this work was published in IEEE Sensors Journal (10.1109/JSEN.2021.3072448). All the above-fabricated biosensors were electrically and optically characterized to validate the outcome.
Supervisor: Prof. Neeraj Sharma & Dr. Sanjeev Kumar Mahto, School of Biomedical Engineering, IIT (BHU), Varanasi, India
Research outcome: 1 Indian patent (status-Filed)
5 research articles (published).
2 Awards & 1 Travel grant