02834nas a2200253   4500008004100000022001400041245007900055210006900134260007100203300001400274490000700288520198600295653001402281653002002295653001302315653000802328653002602336653001802362100001902380700001902399700002702418700002202445856011302467       2013                        eng d  a0897-475600aLarge centimeter-sized macroporous ferritin gels as versatile nanoreactors0 aLarge centimetersized macroporous ferritin gels as versatile nan  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC  a4813-48190 v253 a<p>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.</p>10acatalysis10acontinuous flow10aferritin10agel10amacroporous materials10aSelf-assembly1 aKumari, Sushma1 aKulkarni, Amol1 aKumaraswamy, Guruswamy1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/large-centimeter-sized-macroporous-ferritin-gels-versatile-nanoreactors-002193nas a2200253   4500008004100000022001400041245016500055210006900220260000800289300001400297490000700311520130700318653002201625653001201647653002401659653001301683653001801696100002001714700001601734700002001750700001801770700002201788856012901810       2020                        eng d  a2192-650600aSynthesis of phospho-polypeptides via phosphate-containing N-carboxyanhydride: application in enzyme-induced self-assembly, and calcium carbonate mineralization0 aSynthesis of phosphopolypeptides via phosphatecontaining Ncarbox  cMAY  a1053-10640 v853 a<p>An easy synthetic strategy was developed to synthesize the phosphate-functionalized amino acid N-carboxyanhydride (NCA), using simple primary amine initiators to obtain homo and block phospho-polypeptides with controlled molecular weight and molecular weight distribution. The methodology was extended to the synthesis of the end-functionalized homo polypeptides (15 to 50 repeat unit) and block co-polypeptides with PEG (0.7 K, 2 K, and 5 K) and glycopolypeptide (15-unit mannose glycopolypeptide) as one of the blocks. The deprotected fully water-soluble anionic phosphate-based polypeptides showed pH-dependent helical conformation with a helical content of 20 %, which further changed to beta-sheets upon addition of the enzyme alkaline phosphatase (ALP) due to dephosphorylation. The block co-polypeptide containing PEG as one of the blocks led to its self-assembly into colloidal structures, such as vesicles with a hydrodynamic diameter of similar to 250 nm, due to the formation of amphiphilic block co-polymer upon dephosphorylation. The nature of the colloidal structures formed can be temporally controlled by the extent of dephosphorylation. Finally, the phospho-polypeptides serve as a template for the mineralization of calcium carbonate with varying polymorphs and morphologies.</p>
10aBiomineralization10aenzymes10aphosphopolypeptides10aProteins10aSelf-assembly1 aMondal, Basudeb1 aDas, Soumen1 aPanda, Sidharth1 aDutta, Tahiti1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/synthesis-phospho-polypeptides-phosphate-containing-n-carboxyanhydride-application-enzyme