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1

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

Rył Anna, Owczarz Piotr

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 2

art. no. e9

EN

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.

2

Influence of fish collagen on viscoelastic properties and sol-gel phase transition of chitosan solutions

Rył A., Owczarz P.

Acta Innovations

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2018

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no. 27

14--23

EN

The thermosensitive hydrogels are widely used in tissue engineering due to their non-invasive application. Special interest of researchers, due to the specific characteristics of both materials, is aimed at composites of natural origin obtained from chitosan hydrogels combined with collagen. The mechanical properties of the thermosensitive chitosan-fish collagen hydrogels and the sol-gel phase transition parameters were determined by the rotational rheometry measurement techniques. Based on comparison of the obtained storage modulus G' curves, it was found that the addition of collagen negatively affects the mechanical properties of composite scaffolds. The addition of this protein substance decreases their elasticity. Only the smallest concentration (0.25g collagen/1 g chitosan) of collagen improves the mechanical properties of composite hydrogels, from 56 kPa to 61 kPa. Conducted non-isothermal studies allowed to conclude that the addition of collagen causes an increasing temperature of sol-gel phase transition. However, the observed changes are not a monotone function of the biopolymer concentration.

3

Układy polimerowe formowane in situ do zastosowań biomedycznych. Cz. I. Implanty wstrzykiwalne

Śmiga-Matuszowicz M., Korytkowska-Wałach A., Łukaszczyk J.

Polimery

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2015

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T. 60, nr 3

149--159

PL

Artykuł stanowi przegląd literatury (111 poz. lit.) dotyczącej polimerowych implantów formowanych w miejscu wprowadzenia do organizmu. Materiały takie mogą pełnić zarówno funkcję konstrukcyjną, jak też służyć jako nośnik substancji bioaktywnych. Implanty formowane in situ (ISFI) można otrzymać w wyniku reakcji grup funkcyjnych składników układu lub w wyniku procesów fizycznych. Omówiono ISFI stosowane w charakterze rusztowań wstrzykiwalnych, przeznaczonych do wspomagania regeneracji tkanek, a także wykorzystywane jako układy kontrolowanego uwalniania leków, ze szczególnym uwzględnieniem preparatów używanych w praktyce klinicznej. Skoncentrowano się na układach formowanych w wyniku separacji fazy stałej, opartych na poliestrach alifatycznych zaakceptowanych do zastosowań biomedycznych. Omówiono skład takich układów oraz wpływ rodzaju rozpuszczalnika i masy molowej użytego polimeru na szybkość tworzenia implantu, a także kinetykę uwalniania zawartej w nim substancji bioaktywnej.

EN

The paper is a literature review with 111 references on the polymeric implants forming in the site of incorporation into organism. This kind of materials may have only a structural function, but they can also serve as carriers of bioactive compounds in the treated site. In situ forming implants (ISFI) can be obtained by reaction of functional groups contained in the system components or as a result of physical processes. ISFI serving as injectable scaffolds intended for tissue regeneration and the requirements that should be fulfilled by these materials are presented. Also, various ideas for using ISFI as controlled drug delivery systems, in particular clinically used materials, are described. The attentionis focused on the systems solidifying by solid phase separation, based on aliphatic polyesters accepted for biomedical applications. The composition of these systems and the influence of solvent and polymer molecular weight on the rate of implant formation as well as kinetics of bioactive substance release are discussed.