Prof Pandey introduced Biosensors research in India contributing innovative development on the technology of electrochemical biosensors that involve the immobilization of biological/chemical sensing elements within thin membrane at the surface of electrochemical transducers. His contributions on microporous thin film goes to the electro-synthesis of polyindole introducing the novel synthetic rout for deriving hydrophobic polyindole and simultaneously hydrophilic polymer from indole derivative for desired processing of porous membrane. The contribution on other conducting polymer e.g. ion sensing polyaniline and polypyrrole add further innovative approach. Owing to the known limitation of microporous thin film derived from conducing polymer such as limited control of sensing element within membrane matrix and sluggish charge transport during electrochemical sensing, He contributed on understanding the bioelectrochemistry of tetracyaboquinodimethane-as electron transfer relay within graphite paste electrode for developing various enzyme biosensors and for which he received US Patent and PCT Patent. The problem associated to leaching out of sensing components from such microporous membrane, directed to develop nanoporous thin film derived from functional alkoxysilanes first time in India. He first time reported the specific interaction of amine- and epoxy-functionality linked to alkoxysilane precursors for developing biocompatible nanoporous membrane/thin film of organically modified silicate (Ormosil) that introduced bioelectrocatalysis within nanostructured domains. The finding on the electrochemical generation of redox enzyme and electrocatalysis of H2O2 within such nanostructured films has been major finding. While incorporating electron-transfer relay like ferrocene derivative together redox enzyme, sluggish electrochemistry and poor mediated bio-electrochemical response led to introduce electrocatalytic material within nano-structured matrix of ormosil. He investigated first time the specific interaction of palladium chloride and 3-glycidoxypropyltrimethoxysilane yielding the formation palladium linked nanoporous membrane useful for faciliated bioelectrocatalysis introducing novelty in both scienctific and technological developments. In order to further increase the content of palladium within nanostructured network, He investigated first time the formation of- Pd-Si- linkage while going through the interaction between palladium chloride and trimethoxysilane. The presence of -Pd-Si- linkage and Pd-glymo-complex yielded into the formation of nanostructured membrane behaving as solid-solution. Such matrix yielded excellent redox electrochemistry of ormosil-encapsulated ferrocene monocarboxylic acid even better than that recorded in homogeneous solution and was able to efficiently catalyze the regeneration of various redox enzyme encapsulated within nanoporous thin film. The demand of further enhancing the presence of noble metal component within such nanoporous thin film, He first time invented the role of functional alkoxysilane in the controlled synthesis of gold, silver and palladium nanoparticle introducing new and novel rout of noble metal nanoparticle synthesis for wider practical appllication as compared to that of the same derived from conventional processes . He investigated that 3-aminopyltrimethoxysilane capped noble metal ions are precisely converted into respecting nanoparticles in the presence of 3-glycodoxupropyltrimethoxysilane silane inventing novel rout of functional nanoparticle synthesis that can be converted into nanostructured thin film or may be used as homogeneous suspension with tunable functionality and nanogeometry. The role of many organic reagents along with 3-APTMS has been invented for controlling the dispersibility in desired solvents and for specific applications of all noble metal nanoparticles.
While working on oxidase catalyzed reaction in commercial biosensors development, the requirement of hydrogen peroxide sensing has been another innovative finding by Prof Pandey. Poor sensitivity of electrochemical reduction and large overvoltage in direct oxidation of the same directed for innovative research. His innovation start from the observation on electrocatalytic oxidation and reduction of H2O2 on nanostructured thin film modified electrode made derived from the specific interaction of functional alkoxysilanes. A library of electrocatalytic sites involving the combination of nanostructured domains have been innovative finding. Such innovation again let to the novel rout of polycrystalline processable Prussian blue nanoparticles, commonly referred as artificial peroxidase, synthesis involving 3-APTMS mediated controlled conversion of potassium hexacyanoferrate in the presence of cycloheanone having excellent redox activity with electron transfer rate constant to the order of 32s-1. The novel nanomaterial display excellent electrocatalytic and peroxidase mimetic ability for practical applications in hydrogen peroxide sensing. The process again allow controlled synthesis of polycrystalline mixed metal hexacyanoferrate with nearly all combination of transition metal ions displaying super peroxidase mimetic ability. Further innovation was made on these lines by the use of tetrahydrofuran hydroperoxide that allow PBNPs synthesis even in absence of 3-APTMS.
Purification of biomolecules has been one of the prime attention for biosensors resurch that enabled 100% purification of many active biomolecules like urease, bacteriorhodopsin and chlorophyll. The isolaton and purification of Bacteriorhodopsin has been first time successfully completed in India and the material is available at commercial scale for users in Indian continent.