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New instrumental criterion for evaluating the potential of injectable scaffolds for biomedical engineering applications

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Rył A. , Owczarz P.

Chemical and Process Engineering : New Frontiers

2023

tom Vol. 44, nr 2

art. no. e9

When designing injectable scaffolds for biomedical applications, it is crucial to determine the conditions for the formation of unlimited structures, in particular the kinetics at constant temperature. Despite many studies, these conditions have not been characterized so far after injection, which is such an important application aspect. The aim of the research is to discuss the impact of the injection application on the polymer structure and to propose new criteria for assessing the potential of thermosensitive biopolymer sols, considering the flow under high shear rates during the administration. Based on the analysis of the obtained results of rheological tests, it was shown that the flow through the needles causes a significant change in the elastic properties that define the polymer structure, with almost unchanged viscous properties. As a consequence, the parameters characterizing the polymer coil change, which, combined with the quantitatively proven fragmentation, indicates that injection application may affect the size of the coils that will not reach the critical size of the aggregating nucleus. Finally, extended research procedures for the conscious design of injectable scaffolds are proposed as well as key rheological parameters to ensure thermoinduced aggregation preceded by shear during injection are provided.

Influence of shear direction on gelation ability of colloidal chitosan solutions

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Rył A. , Owczarz P.

Chemical and Process Engineering

2019

tom Vol. 40, nr 2

207–-212

This paper discusses the influence of the direction of applied deformation on the ability to gelation of thermosensitive chitosan hydrogels. The application of the shear rate equal in value to the classically performed oscillatory measurements leads to significantly different shapes of experimental curves. It was found that the type of mechanically applied deformation has a significant impact on the gelation ability of colloidal chitosan solutions and conditions of sol-gel phase transition. Simple shear leads to a phase transition at a lower temperature or in a shorter time compared to oscillatory tests. Moreover, based on the final values of dynamic viscosity in rotational measurements, it was found that stronger crosslinking of the polymer structure was observed.

Badanie wpływu konfekcjonowania na właściwości fizyczne emulsji kosmetycznych

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Sobiecka E. , Jaśniewskia P. , Szymańska K. , Owczarz P. , Olejnik T. P.

Przemysł Chemiczny

2020

tom T. 99, nr 6

957--960

Określono gęstość, lepkość oraz właściwości reologiczne wybranej emulsji produkowanej w skali przemysłowej na dwóch etapach procesu jej konfekcjonowania (półprodukt oraz wyrób gotowy). Dozowanie półproduktu do opakowań końcowych nie wpływało na gęstość emulsji, ale zmieniało lepkość produktu końcowego i jego właściwości reologiczne. Przeprowadzone badania pozwoliły ustalić optymalne parametry procesu konfekcjonowania.

Five samples of semi-finished and 5 samples of final cosmetic emulsions were studied for rheol. properties at 2 stages of the confectioning process. D., viscosity and dynamic viscosity were detd. and used for establishing flow curves according to Ostwald-de Waele and Herschel-Bulkley models. The shearing stress increased and the dynamic viscosity of all emulsions decreased with increasing the shearing rate both for semi-finished and final emulsions.