Executive Summary : | Objective: Overall aim of the proposal is to investigate the potential of catechol/catecholamine rich polymers (CRP), carbon nanomaterials (CN) and metal nanoparticles (MNP) based smart nanocomposite to develop electrochemical biosensors for Mycobacterium tuberculosis (Mtb) detection Chemical synthesis of CRP/CN/MNP based smart nanocomposites and their detailed physical, chemical and electrochemical characterization Development of nanocomposite based bioelectrodes by first depositing them on screen printed electrodes or glassy carbon electrodes followed by covalent immobilization of probe DNA specific to M. Tuberculosis on the electrode surface. Investigating the biosensing performance of the designed bioelectrodes for Mtb detection using electrochemical techniques including cyclic voltammetry, electrochemical impedance spectroscopy etc. Miniaturization of the optimized bioelectrodes by integrating it with the microfluidics technology.Validation of all the fabricated bioelectrodes with standard laboratory and clinical samples Summary: In recent years, biosensors opened up a new horizon in fast, sensitive and selective detection of the disease, reducing interval time between sampling and diagnostic result. Herein, we are proposing a new material based strategy to design highly sensitive DNA based electrochemical TB biosensor using smart conducting nanocomposite constituted of carbon nanomaterials (CN; Graphene, Carbon Nanotubes, Carbon Dots), metal nanoparticles (MNP) and catechol/catecholamine rich polymers [CRP; e.g. Polydopamine (pDA)]. Discovered in 2007, pDA surface modification has been emerged as very efficient and universal approach in modifying and functionalizing any material surface without hampering their intrinsic properties. Integrating CRP in CN/MNP will provide following benefits in biosensor designing: i) CRP surface modification will enrich material surface with nucleophilic –NH2, –OH and =O (quinone) moieties which can be used for covalent immobilization of biomolecules through Schiff base formation and Michael addition. This will help bypassing the –OH and –COOH group functionalization of CN (by strong acid treatment) that usually leads to partial destruction of their sp2 network and thus lowering their conductivity ii) CRP is found to enhance the electrocatalytic and photoluminescence properties of CN thus improves the sensitivity of biosensors. CRP consists of quinone and hydroquinone sub-units to facilitate efficient biomolecule-matrix electron transfer. iv) CRP provides inert, biocompatible and anti-biofouling coating to the material surface. v) CRP based bioinspired surfaces can be easily used as a support to anchor active MNP. Thus, CRP/CN/MNP nanocomposites enfolds all promising features required to design efficient biosensor system and are worth-exploring materials for the development of robust, highly sensitive and selective electrochemical genosensors for TB diagnosis. The best performed biosensing systems will then be integrated with microfluidics technique to develop a point-of-care portable device for Mtb detection. This work can be extended further to design sensors/biosensors for other clinically and environmentally important contaminants/toxicants/analytes. |
