Factors That Influence Base-Catalyzed Thiol-Ene Hydrogel Synthesis

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Injectable hydrogels for localized drug delivery offer tunable release and non-swelling properties.
• Current ethoxylated trimethylolpropane tri-3-mercaptopropionate (ETTMP) and poly(ethylene glycol) diacrylate (PEGDA) hydrogel synthesis faces challenges including poor solubility, slow gelation, and reproducibility issues.

Purpose of the Study:

• To develop a reliable and reproducible synthesis procedure for ETTMP-PEGDA hydrogels.
• To overcome limitations of existing synthesis methods, including slow gelation and poor ETTMP solubility.

Main Methods:

• Investigated the impact of residual mercaptopropionic acid and alumina purification column height on gelation time.
• Premixed ETTMP and PEGDA to enhance ETTMP solubility in water.
• Conducted a sensitivity analysis of key variables in the synthesis process.

Main Results:

• Achieved hydrogel synthesis with polymer concentrations from 15 to 90 wt%.
• Reduced gelation times to under 2 minutes.
• Obtained tunable hydrogel moduli ranging from 3.5 to 190 kPa.
• Demonstrated ETTMP-PEGDA mixture stability at -20 °C for up to 2 months.

Conclusions:

• The developed synthesis procedure provides a reliable method for producing ETTMP-PEGDA hydrogels.
• These improved hydrogels are suitable for injectable, localized drug delivery with controllable drug release.
• The enhanced storage stability facilitates easier handling, storage, and shipment of the hydrogel precursor mixture.