title: E. coli imprinted nano-structured silica micro-granules by spray drying: optimization of calcination temperature.
abstract: We have synthesized nano-structured silica-Escherichia coli composite micro-granules by spray drying of mixed suspension of silica and E. coli through evaporation-induced assembly. Synthesized micro-granules were subjected to calcination in order to form shape-matched macro-pores by removing the bacterial cells. The optimization of calcination temperature is crucial because calcination process leads to two contrasting effects, namely, (i) removal of E. coli from the granules and (ii) alteration of mesoscopic structure in the silica network. We have used small-angle neutron scattering and thermo-gravimetric analysis to determine the optimum temperature for calcination of these granules. It was found that calcination in the temperature range of 200°C to 400°C removes the cells without significant alteration of the nano-structured silica network. However, beyond 500°C, calcination results significant coalescence between the silica particles. Calcination at 600°C eventually collapses the meso-pore network of silica interstices.
authors: Solid State Physics, Division Bhabha Atomic Research Centre, Mumbai 400085, India. Electronic address: debasis@barc.gov.in.
authors: D
authors: D
authors: Sen
authors: Solid State Physics, Division Bhabha Atomic Research Centre, Mumbai 400085, India.
authors: J
authors: J
authors: Bahadur
authors: Solid State Physics, Division Bhabha Atomic Research Centre, Mumbai 400085, India.
authors: Avik
authors: A
authors: Das
authors: Solid State Physics, Division Bhabha Atomic Research Centre, Mumbai 400085, India.
authors: S
authors: S
authors: Mazumder
authors: Nuclear Agriculture and Biotechnology, Division Bhabha Atomic Research Centre, Mumbai 400085, India.
authors: J S
authors: JS
authors: Melo
authors: Julich Centre for Neutron Science, FRM-II, Garching, Germany.
authors: H
authors: H
authors: Frielinghaus
authors: Atominstitut der Osterreichischen Universitaten, A-1020 Wien, Austria.
authors: R
authors: R
authors: Loidl
mesh_terms: D004926:Escherichia coli / Q000502:physiology* / Q000648:ultrastructure; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D033363:Neutron Diffraction; D053838:Scattering, Small Angle; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D012822:Silicon Dioxide
keywords: Calcination; E. coli; Evaporation induced assembly; Micro-granules; SANS; Spray drying