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Soft hydrogels from tetra-functional PEGs using UV-induced thiol-ene coupling chemistry: a structure-to-property study
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.ORCID iD: 0000-0003-0319-6494
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.ORCID iD: 0000-0002-9200-8004
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.ORCID iD: 0000-0002-9372-0829
2014 (English)In: RSC Advances, ISSN 2046-2069, Vol. 4, no 57, 30118-30128 p.Article in journal (Refereed) Published
Abstract [en]

In this work, photo-induced thiol-ene coupling (TEC) was used to produce well-defined poly(ethylene glycol) (PEG)-based hydrogels. PEGs of four different molecular weights (2k, 6k, 10k, and 20k) were functionalized with G1-allyl dendrons using anhydride chemistry to produce tetra-functional TEC crosslinkable PEGs. The tetra-functional PEGs were subsequently crosslinked with a tri-functional thiol in ethanol to form hydrogels. The synthesized hydrogels were characterized with respect to swelling behaviour, rheological properties and hydrolytic degradation. It was found that the molecular weight of the PEG chain greatly influences the final properties of the hydrogel, where a higher molecular weight of PEG gives an increased weight swelling ratio from 240% for PEG-2k hydrogels to 1400% for PEG-20k hydrogels, as well as decreased elastic moduli, with Young's moduli ranging from 106 MPa to 6 MPa, for PEG-2k and PEG-20k hydrogels, respectively. It was also found that the hydrolytic stability in alkaline conditions (pH 10) decreased when the molecular weight of PEG in the hydrogels increased.

Place, publisher, year, edition, pages
2014. Vol. 4, no 57, 30118-30128 p.
National Category
Polymer Technologies
URN: urn:nbn:se:kth:diva-150946DOI: 10.1039/c4ra04335aISI: 000340497600022ScopusID: 2-s2.0-84904438439OAI: diva2:745925

QC 20140911

Available from: 2014-09-11 Created: 2014-09-11 Last updated: 2016-01-25Bibliographically approved
In thesis
1. Thiol-Ene CHemistry and Dopa-Functional Materials towards Biomedical Applications
Open this publication in new window or tab >>Thiol-Ene CHemistry and Dopa-Functional Materials towards Biomedical Applications
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Thiol-ene chemistry is versatile and efficient and can be used as a powerful tool in polymer synthesis. In this thesis, the concept of thiol-ene chemistry has been central, where it has been explored as a tool for the synthesis of well-defined hydrogels and dopa-functional materials towards biomedical applications; such as hydrogels, primers for adhesive fixation of bone fractures, self-healing gels, and micelles for drug-delivery.

Using thiol-ene chemistry, well-defined hydrogels were realized in order to study how the structure influences properties such as swelling, stiffness and hydrolytic degradation. It was found that all these characteristics are related to each other, as a more loosely crosslinked hydrogel experiences higher swelling, lower stiffness and higher degradation rates.

Dopa-functional materials have gained a lot of interest throughout the years due to the remarkable adhesive properties they possess in wet environments. In the pursuit of new primers towards thiol-ene functional crosslinked bone adhesives, compounds with dopa moieties were proposed. Primers derived from dopamine were found to enhance the adhesion towards bone, and it was concluded that addition of NaOH was essential to achieve good adhesion. The strongest adhesion was achieved when thiol and ene-functional primers were used in combination.

Most synthetic routes to dopa-functional polymers involve several protection and deprotection steps and a more simplistic synthetic route is therefore desired. The possibility of using UV-initiated thiol-ene chemistry to produce dopa-functional polymers was therefore investigated. The resulting polymers were shown to exhibit self-healing properties upon complexation with Fe3+ ions.

Finally, the developed synthetic route was used to produce dopa and allyl-functional triblock-co-polymers. These triblock-co-polymers were then used to form micelles and evaluated as drug-delivery vehicles for the cancer-drug doxorubicin. The micelles were found to have high drug-loading capacities and slow release profiles and showed promising results when evaluated against breast-cancer cells.

Abstract [sv]

Reaktioner mellan tioler och omättade kemiska föreningar utgör ett mångsidigt och effektivt redskap inom polymersyntes. I denna avhandling har begreppet tiol-en kemi varit centralt och kemin har använts för syntes av såväl väldefinierade hydrogeler som dopa-funktionella material. Dessa material har sedan utvärderats mot biomedicinska tillämpningar såsom hydrogeler, primers för fixering av benfrakturer, självläkande geler och kontrollerad läkemedelsleverans.

Tiol-en-kemi har i denna avhandling använts för att framställa väldefinierade hydrogeler som sedan utvärderats med avseende på hur strukturen påverkar egenskaper såsom svällningsgrad, styvhet och nedbrytningshastighet. Det visade sig att alla dessa egenskaper är relaterade till varandra och att lösare tvärbundna hydrogeler uppvisar högre svällning, lägre styvhet och högre nedbrytningshastigheter.

Marina musslor har en exceptionell förmåga att fästa mot olika ytor och på grund av detta har det visats en hel del intresse för dopa-funktionella material genom åren. På jakt efter en primer för att öka vidhäftningen hos benlim proponerades därför föreningar med dopafunktionella grupper. Det visade sig att dopaminderivat kunde förbättra vidhäftningen mot ben och det visade sig även att tillsats av natriumhydroxid var viktigt för att uppnå god vidhäftningsförmåga. Den starkaste vidhäftning uppnåddes när derivat med tiol och omättade bindningar användes i kombination.

Syntes av dopafunktionella material involverar ofta flera reaktionssteg och en förenklad syntesväg är därför att eftersträva. UV-initierad tiol-en-kemi undersöktes därför som en möjlig syntesväg för att framställa dopafunktionella polymerer. Polymererna visade sig ha självläkande egenskaper vid komplexbildning med järnjoner.

Slutligen användes denna syntesväg för att framställa blocksampolymerer. Dessa blocksampolymerer användes sedan för att bilda miceller med lovande resultat vid utvärdering för leverans av läkemedel mot bröstcancer.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. 52 p.
TRITA-CHE-Report, ISSN 1654-1081 ; 2016:3
Thiol-ene chemistry, DOPA, biomedical, UV
National Category
Polymer Chemistry
Research subject
Fibre and Polymer Science
urn:nbn:se:kth:diva-180716 (URN)978-91-7595-811-8 (ISBN)
Public defence
2016-02-19, F3, Lindstedtsvägen 26, KTH, Stockholm, 09:00 (English)

QC 20160125

Available from: 2016-01-25 Created: 2016-01-21 Last updated: 2016-01-29Bibliographically approved

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