The Biomedical instrumentation section is dedicated to research in both pure and applied science and integrated research field involving the principles of Physics, Chemistry, Biotechnology and Instrumentation with principal motives i) to develop the process technology of cholesterol biosensor, ii) to develop biosensors for cancer diagnosis, iii) to synthesize new materials for the development of biosensors for infectious diseases through sustained R&D, research publications, patents, technology transfer, consultancy to industry, national labs etc. The group has also undertaken the integrated M.Tech─Ph.D./ Ph.D. programme on biosensors under Academy of Scientific and Innovative Research (AcSIR) and other collaborative academic institutes. The group is concentrating on the following activities:
Technical Development of Cholesterol Device
Total cholesterol is a useful early indicator of cardiovascular problems; cholesterol contributes to the formation of arterial plaques. This work depicts a convenient analytical test (enzyme-linked) on paper to perform cholesterol detection as a result of Bio-chemical reaction analysis of human serum/blood. Measuring cholesterol level is significant for coronary diseases, liver function, biliary function, intestinal absorption, etc. This drop test mechanism of colour formation is similar to lateral flow test methods currently available in the market for infectious & virus infected disease detection.
Technical development of Paper based Immunosensors
For the low resource settings, WHO developed the ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable) criteria to define the characteristics of an ideal diagnostic test. Non-conventional paper based ELISA techniques have been evolving for the detection of various biomolecules such as glucose, urea and proteins with comprising the ASSURED criteria. In the proteomic approaches for the detection of biomarkers, Immunosorbent assay (ELISA) systems gaining much attention due to its robust platforms with high analytical sensitivity.
Fig 1. Block diagram of Paper based Immunosensor
In this context, the development of paper based sensors have attained lots of interest during recent years, not only because of their obvious advantages with respect to its chemical composition with conducive functional groups for the strong attachment of the sensing elements, but also because of the easy portability, lightweight (~10 mg cm-2), and can be tailored according to the end use. Besides this, paper can be modified chemically to incorporate a wide variety of favourable functional groups such as hydroxyl, carboxyl, amino, that can be covalently bound to proteins, DNA, or small molecules. White Paper matrix for the colorimetric biosensor fabrication is advantageous and preferable, because it provides strong contrast with coloured substrates.
Biosafety management has also become one of the greatest concerns to prevent the transmission of infection. In this regard, fabrication of user friendly biodegradable diagnostic kits and diagnostic tools is urgently required for new generation biosensors.
We have developed the low-cost, smart, intelligent paper based sensor for the qualitative and quantitative detection for cardiovascular disease (Troponin) and cancer
Chitosan encapsulated quantum dots platform for leukemia detection
We report results of the studies relating to electrophoretic deposition of nanostructured composite of chitosan (CS)–cadmium-telluride quantum dots (CdTe-QDs) onto indium-tin-oxide coated glass substrate. The high resolution transmission electron microscopic studies of the nanocomposite reveal molecular level coating of the CdTe-QDs with CS molecules in the colloidal dispersion medium. This novel composite platform has been explored to fabricate an electrochemical DNA biosensor for detection of chronic myelogenous leukemia (CML) by immobilizing amine terminated oligonucleotide probe sequence containing 22 base pairs, identified from BCR–ABL fusion gene. The results of differential pulse voltammetry reveal that this nucleic acid sensor can detect as low as 2.56 pM concentration of complementary target DNA with a response time of 60 s. Further, the response characteristics show that this fabricated bioelectrode has a shelf life of about 6 weeks and can be used for about 5–6 times.
schematic showing fabrication of NA/CS-CdTe/ITO bioelectrode and detail mechanism for EPD of Cs-CdTe colloids.