Publications by authors named "Andrzej Pacek"

Background: Traditional large-scale culture systems for human mesenchymal stem/stromal cells (hMSCs) use solid microcarriers as attachment substrates. Although the use of such substrates is advantageous because of the high surface-to-volume ratio, cell harvest from the same substrates is a challenge as it requires enzymatic treatment, often combined with agitation. Here, we investigated a two-phase system for expansion and non-enzymatic recovery of hMSCs.

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Background: Human mesenchymal stem/stromal cells (hMSCs) are at the forefront of regenerative medicine applications due to their relatively easy isolation and availability in adults, potential to differentiate and to secrete a range of trophic factors that could determine specialised tissue regeneration. To date, hMSCs have been successfully cultured in vitro on substrates such as polystyrene dishes (TCPS) or microcarriers. However, hMSC sub-cultivation and harvest typically employs proteolytic enzymes that act by cleaving important cell membrane proteins resulting in long-term cell damage.

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The effect of ionic strength of agarose solution and quenching temperature of the emulsion on the structure and mechanical strength of agarose-based chromatographic adsorbents was investigated. Solutions of agarose containing different amounts of NaCl were emulsified at elevated temperature in mineral oil using a high-shear mixer. The hot emulsion was quenched at different temperatures leading to the gelation of agarose and formation of soft particles.

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The kinetics of deagglomeration in diluted suspensions of goethite nanopowder, as well as the rheology and morphology of the resulting suspensions, strongly depends on pH. At pH 3, nanopowder can be dispersed as separate nanoparticles, and the resulting suspension is Newtonian, with the viscosity only marginally higher than the viscosity of water. At pH between 5 and 12, nanoparticles tend to reaggregate and form weak aggregates/flocs.

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A novel prototype adsorbent, designed for intensified fluidised bed adsorption processes, was assembled by the emulsification coating of 4% (w/v) porous agarose upon a zirconia-silica solid core. The adsorbent, designated ZSA (particle density 1.75 g/ml, maximum pellicle depth 40 microm), was subjected to physical and biochemical comparison with the performance of two commercial adsorbents (Streamline and Macrosorb K4AX).

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