As the electron beam evaporation method is a high-energy method, the reaction cannot be observed as it occurs. Thus, the current work attempts to use data from the two synthesized and particles to elucidate the mechanism by which the core–shell nanoparticles may form. As single-step synthesis of core–shell materials from elemental gas phase precursors has, to the authors’ knowledge, never been performed before, the mechanism of formation and the factors influencing the synthesis are unknown.
Previous nanopowders synthesized with this method have been produced at kg/h rates. Thus, this method may also be a more economical method of synthesising certain types of core–shell particles. The precursors used are elemental materials rather than chemical compounds which are degraded into the final core or shell materials. In this method, the core–shell particles are synthesized in one-step directly from the gas phase without substrates. Recently, the authors have synthesized core–shell Ag–Si and Cu–Si type particles in a new way using electron beam evaporation. For these established techniques, the mechanisms of formation have been investigated and the various parameters which affect the particle formation are known. However these techniques also involve multiple steps, usually depositing the shell material onto an already formed core structure, and use substrates. Gas-phase synthesis techniques exist and usually involve chemical vapour deposition (CVD) or pulsed laser deposition (PLD). The majority of core–shell particles are synthesised using solution methods and usually involve two steps: synthesis of the core structure followed by coating the core structure with the shell material. Thus, they have found wide applicability in fields such as biomedicine, electrical and semiconducting materials, and catalysts. Additionally, they have been designed so that the shell material can improve the reactivity, thermal stability, or oxidative stability of the core material or to use an inexpensive core material to carry a thin, more-expensive shell material. These particles have been of interest as they can exhibit unique properties arising from the combination of core and shell material, geometry, and design. This information could be used to predict and optimize the purification of large biomolecules and bioparticle in route to the establishment of more effective downstream processes.Core–shell type nanoparticles are a type of biphasic materials which have an inner core structure and an outer shell made of different components. This study provides qualitative and quantitative information about Capto™ Core 700 resin. The DBC 10% at 2 min residence time are 24 and 2 mg/mL for BSA and Tg, respectively. Effective pore diffusivities values in the core are 1.6 × 10 −7 and 0.16 × 10 −7 cm 2/s for BSA and Tg, respectively. For both proteins, the effective pore diffusivity in the core is smaller than in the shell due to additional hindrance by bound protein in the core area. The addition of 500 mM NaCl reduces the binding capacity by less than 50%, showing the ability of the resin to operate at high salt conditions. Both proteins present highly favorable binding isotherms with maximum binding capacities of 55 and 105 mg/mL of total bead volume for BSA and Tg, respectively. The resin average bead size is 90.7 μm with a range of 50–130 μm, the shell thickness is 4.18 µm with a range of 3–6 µm and a standard deviation of 0.55 µm, and the pore radius, obtained by inverse size exclusion chromatography, is 50.4 ± 1.3 nm. The functionalized adsorbing core and the inert shell have the same fibrous structure typical of agarose-based beads. The present study aims to characterize the structure and functional properties of this resin using bovine serum albumin (BSA, Mr~65 kDa) and thyroglobulin (Tg, Mr~660 kDa) as model impurity proteins. Capto™ Core 700 is a core-shell chromatographic support with an adsorbing core contained within an inert shell layer designed to purify larger biomolecules and bioparticles in a flow-through mode.
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