Development and characterization of a third-generation S-protected alginate-cystine thiomer
Tomás Fernández-Martínez1, Joao Aguilar2, Susana A Sánchez2
1Biobased and Bioinspired Biomaterials Research Group and Laboratory of Functional Polymers and Environment, Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
International Journal of Biological Macromolecules
|July 5, 2026
Summary
This study introduces a stable, S-protected thiomer based on alginate and cystine. This advanced thiomer demonstrates significantly enhanced mucoadhesion and biocompatibility for drug delivery applications.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Drug Delivery
Background:
- Thiomers enhance mucoadhesion via disulfide bonds with mucin.
- Conventional thiomers have oxidative instability and limited shelf life due to free thiol groups.
Purpose of the Study:
- To synthesize and characterize a stable, 3rd-generation S-protected thiomer.
- To improve mucoadhesion and shelf life compared to 1st-generation thiomers.
Main Methods:
- Alginate was modified with cystine using carbodiimide chemistry.
- Characterization involved FTIR, 13C NMR, TGA, and thiol/disulfide quantification.
- Mucoadhesion was assessed using rheology with porcine mucin and ex vivo fish intestine models.
Main Results:
- The S-protected thiomer exhibited enhanced structural stability and a higher disulfide-to-thiol ratio.
- Rheological studies showed a significant increase in elastic behavior and viscosity.
- Ex vivo assays confirmed mucoadhesiveness, and biocompatibility was validated through hemolysis and cytotoxicity tests.
Conclusions:
- The cystine-modified alginate (S-protected thiomer) offers improved chemical stability and mucoadhesion.
- This 3rd-generation thiomer presents a promising platform for advanced drug delivery systems.
- The developed thiomer demonstrates excellent biocompatibility and stability for pharmaceutical applications.
