Disulfide-Cross-Linked Tetra-PEG Gels
Zhao Meng1,2, Lucas Löser3, Kay Saalwächter3
1Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL), Bâtiment MXD, Station 12, CH-1015 Lausanne, Switzerland.
Macromolecules
|April 15, 2024
Summary
This study explores creating disulfide-cross-linked polymer gels using self-reactive poly(ethylene glycol) macromers. Network structure depends on macromer concentration, offering potential for reduction-sensitive hydrogels in biomedical applications.
Area of Science:
- Polymer Chemistry
- Materials Science
- Biomedical Engineering
Background:
- Polymer gels with defined topologies are often made using specific cross-linking methods.
- Four-arm star-shaped poly(ethylene glycol) (Tetra-PEG) is a versatile precursor for network synthesis.
- Traditional Tetra-PEG gels use heterocomplementary reactive precursors.
Purpose of the Study:
- To investigate the formation and structure of disulfide-cross-linked Tetra-PEG gels using self-reactive thiol-end functional Tetra-PEG macromers.
- To understand how macromer concentration influences network connectivity and topology.
- To evaluate the potential of these disulfide-cross-linked gels as reduction-sensitive hydrogels.
Main Methods:
- Synthesis of disulfide-cross-linked Tetra-PEG gels from thiol-end functional Tetra-PEG macromers.
- Characterization of gel structure using multiple-quantum NMR (MQ-NMR) spectroscopy.
- Analysis of network connectivity and topology via small-angle neutron scattering (SANS) experiments.
Main Results:
- Network connectivity strongly depends on the concentration of the thiol-end functional Tetra-PEG macromer.
- Gels synthesized below the overlap concentration exhibit a higher proportion of defect connectivity motifs (loops, dangling ends).
- Above the overlap concentration, disulfide-cross-linked gels show similar single-link connectivities to amide-cross-linked Tetra-PEG gels.
Conclusions:
- Self-reactive thiol-end functional Tetra-PEG macromers can form disulfide-cross-linked gels with tunable network structures.
- Macromer concentration is a critical parameter controlling gel topology and defect formation.
- The susceptibility of disulfide bonds to reductive cleavage makes these gels promising for biomedical applications requiring sensitivity to reduction.
