►Research Interests
►Research Interests
Design and development of low cost, portable and user-friendly analytical methodologies are pressing need in various practical applications. In this respect, we are successful in developing disposable type of screen-printed electrodes and its chemically- or biochemically- modified matrixes suitable for selective sensing of target molecules which including biomedical, industrial, pharmaceutical samples with qualitative and quantitative manner. Hence our research topics span over Materials Science and Physical Chemistry to search for active reagents suitable for chemically modified SPE preparation and further to analytical measurements.
Note: Such a technological Advancements are still at R & D level and commercial application is not yet achieved in India so for.
1. High-Valent RuVIIOx stabilized matrixes
First time in the literature, we discovered unusual stabilization of a high-valent Ru(VII) oxidation state (Eo ~1.45 V vs RHE) in within low-valent RuO2 and macromolecular Prussian blue RuOx combinatory matrixes (RuOx-PB) without any classical disproponation-decomposition reaction in acidic pH’s and further demonstrated for an efficient electrocatalytic oxidation to carbohydrates (glucose), alcohol and aldehydes. Note that the Ru(VII) so for believed to stable in strong-alkaline condition and at pH<12, it tends to decompose to lower oxidation state like Ru(IV) and Ru(IV).
2. Biomimicking enzyme analogues
2a. Lead-Ruthenium Oxide-Pyrochlore (Pb2RuO7)/polymeric Nafion ® catalyst
Nafion (Nf) + {Ru2(m-O)}complex ® Nf-{Ru2(m-OH)}colloids
Lead-ruthenium oxide pyrochlore internally precipitated Nafion® membrane ((½NPycx-Ru(bpy) ½) discovered as a stable, easy recoverable, highly reusable and selective catalyst for benzyl alcohol oxidation to benzaldehyde reaction (solution phase catalysis). Similarly, Lead-ruthenium oxide pyrochlore (Pyc) catalyst internally precipitated and photosensitizer (Ru(bpy)32+) doped Nafion® membrane system (½Npycx-Ru(bpy) ½) has been demonstrated for selective and efficient heterogeneous organic sulfur (RSCH3) photo-oxidation to sulfoxide (RSOCH3) reaction using O2 as a co-oxidant (scheme given in left side; three-phase membrane catalyst).
2b. Artificial Peroxidase
Ruthenium purple (Fe-RuCN) anchored industrially waste cinder is discovered for the stable artificial peroxidase analogue suitable to glucose biosensor application in couple with bovine albumin serum (BSA), glucose Oxidase enzyme (GOD) and a Tosflex® polymer over-layer coating.
2c. Biomimicking of Non-Heme enzymes
Effective biomimicking enzyme sensor (scheme given in left side) is developed on a glassy carbon electrode (GCE) surface and further to sensing of various biological (cysteine, dopamine, hypoxathine, xanthine & uric acid), environmental (dissolved oxygen, codeine and amitrole) and industrial (hydrazine) samples by suitably tuning the sensor and solution characteristics with a detection range down to nanomolar levels. In this model, the Nafion® core and catalyst mimics the macro-protein structure and active sites corresponding in the enzyme systems.
Non-heme enzymes comprise of m-OH and m-carboxylato diiron core applicable for many significant chemical transformations including a membrane bound bacterial nitric oxide reductase (NOR-FeB) for irreversible nitric oxide (NO) reduction reaction. Even though variety of biomimicing models were developed, functional applications is almost nil so for. The m-OH core always gets decomposed in acidic solutions. We first developed a Nafion® membrane stabilized diruthenium non-heme complex (Nf-{Ru2(u-OH)}) matrix (active particle size = 4.1nm) for a selective electrocatalytic reduction of nitrosonium ion in aqueous solution. The approach can be extendable for practical sensor applications.
3. Hybrid Prussian Blue (PB) Catalyst
First time in the literature, we synthesized a hybrid PB analogue PB directly inside the iron ion rich clay (nontronite) or industrially waste cinder matrix. PB (-AxByCN-) has macromolecular structure with zeolite type internal framework used and stable in acidic pH’s. The new hybrid system showed fascinating property with stable internal structure even to neutral pH’s also (which is suitable to biosensor in physiological systems). The new system has tremendous application in electro-chromic devices, chemical sensor, and catalytic applications.
4. Nanoparticle for Bio-molecular recognition
Electrochemical plating methods were developed to prepare fine metal-nano particle electrodes suitable for selective biochemical applications. In this regards, 100 nm particle size copper (Cun)-plated screen-printed type disposable electrodes is demonstrated for selective amino acids recognition through specific complexation mechanism.
5. Biosensor
Copper screen-printed system is first time introduced for the glucose biosensor applications and intriguing mechanistic aspects were evaluated in term of mixed-potential pathways.
6. Chemically Modified Electrodes (CMEs)
Tailor made CMEs were developed suitable for the selective recognition and catalysis of target molecules from industrial, environmental, biochemical and clinical samples. The approach includes preparation, characterization and applications of new and novel CMEs.
7. Heterogenous (multi-component) membrane catalyst
8. Screen-printed electrodes (SPEs) based chemical & Bio-chemical sensor