Doctoral Thesis

Tuneable Viscoelastic Hydrogels from Sustainable Biopolymers: Design and Characterisation

Author of thesis: Ing. Nicole Talaš Černeková

Acad. year: 2025/2026

Supervisor: prof. Ing. Adriána Kovalčík, Ph.D.

Reviewers: doc. RNDr. Ondřej Sedláček, Ph.D., prof. Ing. Vladimír Sedlařík, Ph.D.

Abstract:

This dissertation thesis designs sustainable hydrogels with tuneable viscoelasticity, swelling and transport properties. The first part describes the preparation and characterisation of hydrogels based on agarose, gellan gum and carrageenan. Due to its low viscoelastic strength, carrageenan hydrogel was selected for further modification with two biopolymers – poly(3-hydroxybutyrate) (PHB) and lignin. Composite carrageenan hydrogels containing PHB nanoparticles, prepared via nanoprecipitation, exhibited higher viscoelastic strength, slightly reduced swelling and slower release of active substances. Lignin-modified hydrogels formed semi-interpenetrating networks with increased viscoelastic moduli and antioxidant properties. The addition of PHB or lignin allows regulation of swelling and release rates, which is valuable for biomedical applications. The next part focuses on hydrogels prepared directly from polyhydroxyalkanoates (PHAs) – PHB and its copolymer. Despite their hydrophobic nature, hydrophilic hydrogels were successfully prepared, and agarose and polyvinyl alcohol were tested as additives. These hydrogels showed high strength, flexibility and efficient absorption and release of model substances. In the final part, PHA hydrogels were coated with a layer of polypyrrole using oxidative chemical vapour deposition (oCVD). Optimisation of oxidant loading and deposition conditions yielded electrically conductive hydrogel composites. Overall, the dissertation establishes a toolbox for mechanical and transport tuning in sustainable hydrogels, spanning polysaccharide blends, PHA-based networks and oCVD-functionalised composites, highlighting their potential for controlled release, biointerfaces and soft bioelectronics.

Keywords:

Hydrogels; polysaccharides; viscoelasticity; nanoparticles; lignin; polyhydroxyalkanoates (PHA); release; atomic force microscopy (AFM); conductivity.

Date of defence

22.01.2026

Date of publish

21.01.2029

Result of the defence

Defended (thesis was successfully defended)

znamkaPznamka

Process of defence

Obhajoba proběhla v angličtině. Předseda komise představil doktorandku a předal jí slovo. Ing. Černeková absolvovala v roce 2025 zahraniční stáž v Nizozemí. Je spoluautorkou pěti publikací, ve dvou případech je uvedena na prvním místě. Je spoluautorkou celé řady konferenčních příspěvků.

Language of thesis

English

Faculty

Department

Study programme

Biophysical Chemistry (DKCP_BCH)

Composition of Committee

prof. Ing. Miloslav Pekař, CSc. (předseda)
doc. RNDr. Ondřej Sedláček, Ph.D. (člen)
prof. Ing. Vladimír Sedlařík, Ph.D. (člen)
prof. Ing. Marián Lehocký, Ph.D. (člen)
Ing. Adam Strachota, Ph.D. (člen)
Ing. Lukáš Nejdl, Ph.D. (člen)
prof. Ing. Martina Klučáková, Ph.D. (člen)

I have known Ing. Nicole Talaš Černeková for seven years, beginning with her bachelor thesis and continuing with her master thesis, both of which she completed under my supervision. These early works were of high quality and received awards, demonstrating her aptitude for independent research already at that stage. Over the years, she developed into a capable and reliable researcher who formulates clear scientific objectives and pursues them with precision and methodological discipline.
During her PhD studies and during her time as a member of my research team, Nicole demonstrated a high degree of independence and responsibility for her work. She consistently maintained a high standard of laboratory practice, approached scientific problems with critical and structured thinking, and delivered well-interpreted and thoroughly documented results. She integrated well into the group environment, readily assisted colleagues, including junior researchers, and contributed to a collaborative and supportive research atmosphere.
Nicole has mastered a range of experimental techniques that are central to her dissertation. She has extensive experience in determining antibacterial activity, performing rheological measurements, and preparing polymer films using solution casting. She also successfully prepared porous PHA-based monoliths using thermally induced phase separation and introduced suitable methodological modifications to meet the requirements of her dissertation project. In all these activities, she worked accurately, reliably, and with a clear understanding.
Her ability to operate effectively in an international research environment was demonstrated during her research stay at the University of Groningen, where she integrated smoothly into a multinational team and managed her tasks independently while contributing meaningfully to joint research efforts.
I consider her dissertation a substantive and original contribution to to the field of biophysical chemistry and I confidently recommend it for defense.
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Reasons for publication postponement

Publication of dissertation thesis is in accordance with the provision of § 47b, paragraph 4 of Act No. 111/1998 Coll., on Higher Education Institutions, postponed. The reason for postponing the publication is the fact that the dissertation thesis, contains information protected by special legal regulations (eg No. 527/1990 Coll., on Inventions and Improvement Proposals).

Responsibility: Mgr. et Mgr. Hana Odstrčilová