Synthesis and characterization of cyclic acetal based degradable hydrogels

Area of Science:

• Biomaterials Science
• Polymer Chemistry

Background:

• Many synthetic degradable hydrogels produce acidic byproducts, limiting their biomedical applications.
• There is a need for hydrolytically degradable hydrogels with neutral degradation products.

Purpose of the Study:

• To develop and characterize novel hydrogels based on a cyclic acetal monomer that degrades into neutral diols and propanals.
• To overcome monomer hydrophobicity challenges in hydrogel fabrication using a co-monomer system.
• To investigate the physicochemical properties of the resulting hydrogels for potential biomedical uses.

Main Methods:

• Free radical polymerization of 5-ethyl-5-(hydroxymethyl)-beta,beta-dimethyl-1,3-dioxane-2-ethanol diacrylate (EHD) and poly(ethylene glycol)diacrylate (PEGDA) using benzoyl peroxide and N,N-dimethyl-p-toluidine.
• Utilized an acetone/water co-solvent system to facilitate polymerization of the hydrophobic EHD monomer.
• Characterized the EH-PEG hydrogel's chemical structure using FT-IR and determined swelling degree, sol fraction, and contact angle.

Main Results:

• Successful fabrication of EH-PEG hydrogels was achieved using the co-solvent system.
• Hydrogel swelling degree was found to be dependent on initiator concentration, monomer concentration, and monomer molar ratios.
• Sol fraction was significantly influenced by initiator and monomer concentrations.

Conclusions:

• The EHD and PEGDA co-monomer system enables the fabrication of novel cyclic acetal-based hydrogels.
• The study demonstrates control over hydrogel properties like swelling and sol fraction by adjusting polymerization parameters.
• These EH-PEG hydrogels show promise for drug delivery and tissue engineering applications due to their tunable and neutral degradation characteristics.