uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Modulating thiol pKa promotes disulfide formation at physiological pH: An elegant strategy to design disulfide cross-linked hyaluronic acid hydrogels
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
Bioengineering and Nanomedicine Lab, Faculty of Medicine and Health Technologies and BioMediTech Institute, Tampere University, Korkeakoulunkatu 3, Tampere 33720, Finland.ORCID iD: 0000-0003-2768-0133
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.ORCID iD: 0000-0001-6947-9601
Show others and affiliations
2019 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, no 3, p. 1412-1420Article in journal (Refereed) Published
Abstract [en]

The disulfide bond plays a crucial role in protein biology and has been exploited by scientists to develop antibody-drug conjugates, sensors and for the immobilization other biomolecules to materials surfaces. In spite of its versatile use, the disulfide chemistry suffers from some inevitable limitations such as the need for basic conditions (pH > 8.5), strong oxidants and long reaction times. We demonstrate here that thiol-substrates containing electron-withdrawing groups at the β-position influence the deprotonation of the thiol group, which is the key reaction intermediate in the formation of disulfide bonds. Evaluation of reaction kinetics using small molecule substrate such as L-cysteine indicated disulfide formation at a 2.8-fold higher (k1 = 5.04 x 10-4 min-1) reaction rate as compared to the conventional thiol substrate, namely 3-mercaptopropionic acid (k1 = 1.80 x 10-4 min-1) at physiological pH (pH 7.4). Interestingly, the same effect could not be observed when N-acetyl-L-cysteine substrate (k1 = 0.51 x 10-4 min-1) was used. We further grafted such thiol-containing molecules (cysteine, N-acetyl-cysteine, and 3-mercaptopropionic acid) to a biopolymer namely hyaluronic acid (HA) and determined the pKa value of different thiol groups by spectrophotometric analysis. The electron-withdrawing group at the β-position reduced the pKa of the thiol group to 7.0 for HA-cysteine (HA-Cys); 7.4 for N-acetyl cysteine (HA-ActCys) and 8.1 for HA-thiol (HA-SH) derivatives respectively. These experiments further confirmed that the concentration of thiolate (R-S-) ions could be increased with the presence of electron-withdrawing groups, which could facilitate disulfide cross-linked hydrogel formation at physiological pH. Indeed, HA grafted with cysteine or N-acetyl groups formed hydrogels within 3.5 minutes or 10 hours, respectively at pH 7.4. After completion of crosslinking reaction both gels demonstrated a storage modulus G’ ≈3300–3500 Pa, indicating comparable levels of crosslinking. The HA-SH gel, on the other hand, did not form any gel at pH 7.4 even after 24 h. Finally, we demonstrated that the newly prepared hydrogels exhibited excellent hydrolytic stability but can be degraded by cell-directed processes (enzymatic and reductive degradation). We believe our study provides a valuable insight on the factors governing the disulfide formation and our results are useful to develop strategies that would facilitate generation of stable thiol functionalized biomolecules or promote fast thiol oxidation according to the biomedical needs.

Place, publisher, year, edition, pages
2019. Vol. 20, no 3, p. 1412-1420
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-375001DOI: 10.1021/acs.biomac.8b01830ISI: 000461270500028PubMedID: 30726668OAI: oai:DiVA.org:uu-375001DiVA, id: diva2:1282442
Funder
Swedish Foundation for Strategic Research , 139400127EU, FP7, Seventh Framework Programme, 607868Swedish Foundation for Strategic Research , 139400126Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2019-04-11Bibliographically approved
In thesis
1. Insights into Covalent Chemistry for the Developmen­t of Biomaterials
Open this publication in new window or tab >>Insights into Covalent Chemistry for the Developmen­t of Biomaterials
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Covalent cross-linking chemistry is currently exploited in the preparation of biomaterial for biomedical applications. Choice of these chemistries for the preparation of biomaterials and bioconjugates strongly influences the biological output of these materials. Therefore, this thesis aims to develop novel bioconjugation strategies understanding their advantages and drawbacks. Our results provide new insight to adapt these chemical transformations for a specific application.

The first part of this thesis points out the relevance of tuning different properties of biomaterials with specific emphasis on the development of hyaluronic acid (HA) hydrogels. The second part of the thesis describes how different chemical transformations including hydrazone formation (Paper I), thiazolidine formation (Paper II), cross-aldol addition reaction (Paper III) and disulfide formation (Paper IV) dictate material properties.

This thesis explores both basic organic reaction mechanism and application of these reactions to influence material characteristics. The detailed study of the reaction conditions, kinetics, and stability of the products will help to understand the mechanical properties, hydrolytic stability, and degradability of the materials described here.

Additionally, we performed degradation studies of gadolinium labeled HA hydrogels using magnetic resonance imaging. Furthermore, we also explored post-synthetic modification of hydrogels to link model fluorescent moieties as well as explored the tissue adhesive properties using Schiff-base formation.

In summary, this thesis presents a selection of different covalent chemistries for the design of advanced biomaterials. The advantages and disadvantages of these chemistries are rigorously investigated. We believe, such an investigation provides a better understanding of the bioconjugation strategies for the preparation of biomaterials with potential clinical translation.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 64
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1768
Keywords
hyaluronic acid, hydrogel, biomaterials, covalent chemistry, biomedical applications, MRI
National Category
Materials Chemistry Polymer Chemistry Organic Chemistry
Research subject
Chemistry with specialization in Materials Chemistry; Chemistry with specialization in Polymer Chemistry
Identifiers
urn:nbn:se:uu:diva-375002 (URN)978-91-513-0564-6 (ISBN)
Public defence
2019-03-14, Häggsalen, 10132, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2019-02-21 Created: 2019-01-24 Last updated: 2019-02-21

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textPubMed

Authority records BETA

Bermejo-Velasco, DanielHilborn, JönsVarghese, Oommen P.

Search in DiVA

By author/editor
Bermejo-Velasco, DanielOommen, Oommen P.Hilborn, JönsVarghese, Oommen P.
By organisation
Polymer Chemistry
In the same journal
Biomacromolecules
Materials Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 169 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf