@article { ISI:000294701600022, title = {Functionalization of SBA-15 mesoporous materials using {\textquoteleft}{\textquoteleft}thiol-ene click{\textquoteright}{\textquoteright} michael addition reaction}, journal = {Journal of Physical Chemistry C }, volume = {115}, number = {36}, year = {2011}, month = {SEP}, pages = {17774-17781}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Methacrylate-labeled SBA-15 has been successfully synthesized from calcined SBA-15 and commercially available 3-trichlorosilyl propylmethacrylate. This material undergoes efficient thiol-ene {\textquoteleft}{\textquoteleft}click reaction{\textquoteright}{\textquoteright} with a variety of both thiol and disulfide-containing substrates in aqueous and organic media. The products were thoroughly characterized by a variety of analytical techniques including multinuclear (C-13, Si-29) solid-state NMR, TG-DTA, and nitrogen adsorption desorption studies. Disulfide-containing substrates in which the TCEP-mediated reduction of the disulfide bond and its subsequent addition to the methacrylate group anchored in SBA-15 in one-pot were used to synthesize a silica-protein hybrid material composed of biotin-labeled SBA-15 and streptavidin. Electrochemically active material was synthesized from the reaction of ferrocene-containing thiol and the methacrylate-labeled SBA-15. The ease of synthesis for the methacrylate-labeled SBA-15 material together with its ability to undergo efficient chemoselective thiol-ene reaction would make it a very attractive platform for the development of covalently anchored enzymes and sensors.

}, issn = {1932-7447}, doi = {10.1021/jp2056442}, author = {Kumari, Sushma and Malvi, Bharmana and Ganai, Anal Kumar and Pillai, Vijayamohanan K. and Sen Gupta, Sayam} } @article { ISI:000303442500017, title = {Synthesis of functional hybrid silica scaffolds with controllable hierarchical porosity by dynamic templating}, journal = {Chemical Communications}, volume = {48}, number = {43}, year = {2012}, month = {MAR}, pages = {5292-5294}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report a facile one-pot synthesis of hierarchically porous scaffolds, with independent control over nanoparticle mesoporosity and scaffold macroporosity. Our technique combines the chemistry of mesoporous silica nanoparticles with the control afforded by dynamic templating of surfactant mesophases. These materials are readily functionalizable and allow controllable spatial variation in macroporosity.

}, issn = {1359-7345}, doi = {10.1039/c2cc30885a}, author = {Ganai, Anal Kumar and Kumari, Sushma and Sharma, Kamendra P. and Panda, Chakadola and Kumaraswamy, Guruswamy and Sen Gupta, Sayam} } @article { ISI:000328437300022, title = {Large centimeter-sized macroporous ferritin gels as versatile nanoreactors}, journal = {Chemistry of Materials}, volume = {25}, number = {23}, year = {2013}, month = {DEC}, pages = {4813-4819}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Organized assemblies of bionanoparticles such as ferritin provides templates that can be exploited for nanotechnological applications. Organization of ferritin into well-defined three-dimensional assemblies is challenging and has attracted considerable attention recently. We have synthesized, for the first time, large (centimeter-sized) self-standing macroporous scaffold monoliths from ferritin bionanoparticles, using dynamic templating of surfactant H-1 domains. These scaffolds comprise three-dimensionally connected strands of ferritin, organized as a porous gel with porosity similar to 55 mu m. The iron oxide inside the ferritin scaffold can be easily replaced with catalytically active monodisperse zerovalent transition metal nanoparticles using a very simple protocol. Since the ferritin is cross-linked in the scaffold, it is significantly robust with enhanced thermal stability and better tolerance toward several organic solvents in Comparison to the native ferritin bionanoparticle. In addition, the scaffold macropores facilitate substrate and reagent transport and hence the monoliths containing active Pd or iron oxide nanoparticles inside apo-ferritin bionanoparticles were used as a recyclable heterogeneous catalyst for the oxidation of 2,3,6-trimethyl phenol to 2,3,6-trimethyl-1,4-benzoquinone (precursor for Vitamin E synthesis) and for Suzuki-Miyaura cross-coupling reaction in both aqueous and organic solvents. The protein shell around the nanoparticles protects them from agglomeration, a phenomenon that otherwise plagues nanoparticles-based catalysis. The presence of macropores allow the ferritin scaffold to act as catalytic monolith for continuous flow reactions having rapid reaction rates, while offering a low pressure drop. Finally, the Pd@apo-ferritin scaffold was immobilized inside a steel cartridge and used for the continuous flow hydrogenation of alkenes to their corresponding alkanes for 15 cycles without any loss of activity.

}, keywords = {catalysis, continuous flow, ferritin, gel, macroporous materials, Self-assembly}, issn = {0897-4756}, doi = {10.1021/cm403240j}, author = {Kumari, Sushma and Kulkarni, Amol and Kumaraswamy, Guruswamy and Sen Gupta, Sayam} } @article { ISI:000341122000068, title = {Fe-TAML encapsulated inside mesoporous silica nanoparticles as peroxidase mimic: femtomolar protein detection}, journal = {ACS Applied Materials \& Interfaces}, volume = {6}, number = {16}, year = {2014}, month = {AUG}, pages = {13866-13873}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Peroxidase, such as horseradish peroxidase (HRP), conjugated to antibodies are routinely used for the detection of proteins via an ELISA type assay in which a critical step is the catalytic signal amplification by the enzyme to generate a detectable signal. Synthesis of functional mimics of peroxidase enzyme that display catalytic activity which far exceeds the native enzyme is extremely important for the precise and accurate determination of very low quantities of proteins (fM and lower) that is necessary for early clinical diagnosis. Despite great advancements, analyzing proteins of very low abundance colorimetrically, a method that is most sought after since it requires no equipment for the analysis, still faces great challenges. Most reported HRP mimics that show catalytic activity greater than native enzyme (similar to 40-fold) are based on metal/metal-oxide nanoparticles such as Fe3O4. In this paper, we describe a second generation hybrid material developed by us in which approximately 25 000 alkyne tagged biuret modified Fetetraamido macrocyclic ligand (Fe-TAML), a very powerful small molecule synthetic HRP mimic, was covalently attached inside a 40 nm mesoporous silica nanopartide (MSN). Biuret-modified Fe-TAMLs represent one of the best small molecule functional mimics of the enzyme HRP with reaction rates in water close to the native enzyme and operational stability (pH, ionic strength) far exceeding the natural enzyme. The catalytic activity of this hybrid material is around 1000-fold higher than that of natural HRP and 100-fold higher than that of most metal/metal oxide nanoparticle based HRP mimics reported to date. We also show that using antibody conjugates of this hybrid material it is possible to detect and, most importantly, quantify femtomolar quantities of proteins colorimetrically in an ELISA type assay. This represents at least 10-fold higher sensitivity than other colorimetric protein assays that have been reported using metal/metal oxide nanoparticles as HRP mimic. Using a human IgG expressing cell line, we were able to demonstrate that the protein of interest human IgG could be detected from a mixture of interfering proteins in our assay.

}, keywords = {colorimetrically, immuno assay, MSN, peroxidase mimic, signal amplification}, issn = {1944-8244}, doi = {10.1021/am503275g}, author = {Kumari, Sushma and Dhar, Basab B. and Panda, Chakadola and Meena, Abhishek and Sen Gupta, Sayam} } @article { ISI:000363167000007, title = {Molecular Fe-complex as a catalyst probe for in-gel visual detection of proteins via signal amplification}, journal = {Chemical Communications}, volume = {51}, number = {83}, year = {2015}, month = {JUL}, pages = {15257-15260}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report the use of a molecular peroxidase mimic biuret-Fe-TAML for chemoselective labeling of proteins and the subsequent visual detection (\<0.1 pmoles) of the conjugate in a polyacrylamide gel by catalytic signal amplification. Use of this probe in activity based protein profiling (ABPP) of serine proteases is also demonstrated.

}, issn = {1359-7345}, doi = {10.1039/c5cc04399a}, author = {Kumari, Sushma and Panda, Chakadola and Mazumdar, Shyamalava and Sen Gupta, Sayam} } @article { ISI:000353702500026, title = {Self-templated chemically stable hollow spherical covalent organic framework}, journal = {Nature Communications}, volume = {6}, year = {2015}, month = {APR}, pages = {6786}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

Covalent organic frameworks are a family of crystalline porous materials with promising applications. Although active research on the design and synthesis of covalent organic frameworks has been ongoing for almost a decade, the mechanisms of formation of covalent organic frameworks crystallites remain poorly understood. Here we report the synthesis of a hollow spherical covalent organic framework with mesoporous walls in a single-step template-free method. A detailed time-dependent study of hollow sphere formation reveals that an inside-out Ostwald ripening process is responsible for the hollow sphere formation. The synthesized covalent organic framework hollow spheres are highly porous (surface area similar to 1,500m(2) g(-1)), crystalline and chemically stable, due to the presence of strong intramolecular hydrogen bonding. These mesoporous hollow sphere covalent organic frameworks are used for a trypsin immobilization study, which shows an uptake of 15.5 mu mol g(-1) of trypsin.

}, issn = {2041-1723}, doi = {10.1038/ncomms7786}, author = {Kandambeth, Sharath and Venkatesh, V. and Shinde, Digambar B. and Kumari, Sushma and Halder, Arjun and Verma, Sandeep and Banerjee, Rahul} } @article {43560, title = {Catalytic macroporous biohydrogels made of ferritin-encapsulated gold nanoparticles}, journal = {Chempluschem}, volume = {82}, year = {2017}, month = {FEB}, pages = {225-232}, abstract = {Reported is a modular approach for the incorporation and stabilization of gold nanoparticles inside a three-dimensional macroporous hydrogel made of ferritin. The strategy, which involves the dynamic templating of surfactant H-1 domains, demineralization, and remineralization helps to overcome aggregation and degradation issues usually associated with bare-metal-based nanocatalysts. The catalytic activity of the so-synthesized bionanocomposite hydrogel was demonstrated in both nitroaldol (Henry) and nitroreduction model reactions in aqueous solution at room temperature. An interesting synergistic effect between basic residues of the protein and the gold nanoparticles was found in the nitroaldol reaction when carried out in water in the presence of a phase-transfer catalyst. Furthermore, the reduction of 4-nitrophenol and 4-nitroaniline catalyzed by the nanocomposite scaffold in the presence of NaBH4 proceeded significantly faster than that using other known Au- and Ag-based catalysts under similar conditions.}, doi = {10.1002/cplu.201600454}, author = {Kumari, Sushma and Haring, Marleen and Sen Gupta, Sayam and Diaz, David Diaz} }