Gellan gum hydrogel as a platform for oxygen monitoring: Covalent immobilization of PtTFPP
Sirén, Sumu (2024)
2024
Bioteknologian ja biolääketieteen tekniikan kandidaattiohjelma - Bachelor's Programme in Biotechnology and Biomedical Engineering
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
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Hyväksymispäivämäärä
2024-04-23
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202404183767
https://urn.fi/URN:NBN:fi:tuni-202404183767
Tiivistelmä
Oxygen monitoring in cell cultures has become increasingly relevant. Ability to monitor oxygen concentrations in cell cultures gives information about cell metabolism and lifespan. This ability combined with hydrogels, biomimicing the biological environments of soft tissues, could allow more detailed monitoring of tissues and their metabolism. Gellan gum has been established as a suitable material for tissue engineering since it has biomimicking properties and is easy to modify. The aim of this work was to establish a protocol for oxygen sensing gellan gum hydrogel. Oxygen sensing molecules, probes, must be covalently immobilized to prevent cytotoxic leaching. In this work an optical oxygen sensing probe, platinum-based porphyrin (PtTFPP), is used. Oxygen sensing is based on the luminescence emission of the molecule that changes when oxygen concentrations vary.
For this, gellan gum hydrogel was modified. First gellan gum was oxidated and the modification degree was analysed with TNBS assay. Then, oxidized gellan gum was thiolated to enable click-chemistry reaction. Two methods were considered in thiolation. Thiolation was confirmed with Ellman’s essay. PtTFPP was immobilized with three varying methods. After covalent immobilization of PtTFPP a UV-analysis and gelation test were performed.
Based on the analysis of aldehydes, 28,3% oxidized gellan gum was modified. From Ellman’s assay, the method that used excessively reagents lead into amend yield of thiolated gellan gum. UV-analysis of covalent immobilization of PtTFPP showed that the method that had the most organic solvent had PtTFPP covalently immobilized. The gelation test showed the side reaction in thiolated gellan gum and none of the samples formed true self-supporting hydrogels.
In future some development for fully functioning oxygen sensing hydrogel must be done. A common solvent that dissolves PtTFPP and gellan gum needs to be found to have the best possible yield. The concentration of PtTFPP in gellan must be adjusted for the true gelation of the hydrogel.
For this, gellan gum hydrogel was modified. First gellan gum was oxidated and the modification degree was analysed with TNBS assay. Then, oxidized gellan gum was thiolated to enable click-chemistry reaction. Two methods were considered in thiolation. Thiolation was confirmed with Ellman’s essay. PtTFPP was immobilized with three varying methods. After covalent immobilization of PtTFPP a UV-analysis and gelation test were performed.
Based on the analysis of aldehydes, 28,3% oxidized gellan gum was modified. From Ellman’s assay, the method that used excessively reagents lead into amend yield of thiolated gellan gum. UV-analysis of covalent immobilization of PtTFPP showed that the method that had the most organic solvent had PtTFPP covalently immobilized. The gelation test showed the side reaction in thiolated gellan gum and none of the samples formed true self-supporting hydrogels.
In future some development for fully functioning oxygen sensing hydrogel must be done. A common solvent that dissolves PtTFPP and gellan gum needs to be found to have the best possible yield. The concentration of PtTFPP in gellan must be adjusted for the true gelation of the hydrogel.