Electrochemical Diffusion Study in Poly(Ethylene Glycol) Dimethacrylate-Based Hydrogels.

Area of Science:

• Materials Science
• Biotechnology
• Analytical Chemistry

Background:

• Hydrogels are crucial for functionalizing sensors and microfluidics.
• Poly(ethylene glycol) dimethacrylate (PEG-DMA) is a common viscosifier for printable hydrogel precursor inks.

Purpose of the Study:

• To characterize PEG-DMA hydrogels for sensor applications.
• To investigate the diffusivity of small molecules and proteins within these hydrogels.
• To explore the potential of hydrogels as reagent reservoirs for biosensing.

Main Methods:

• Characterization of 1-10 kDa PEG-DMA hydrogels using gravimetric and electrochemical methods.
• Calculation of swelling ratios (SRs) and mesh sizes (ξ).
• Electrochemical measurement of methylene blue (MB) and MB-conjugated proteins on modified sensors.

Main Results:

• Swelling ratio (SR) correlates with PEG-DMA molar concentration (MCI).
• Mesh size (ξ) correlates with PEG-DMA molecular weight (Mw).
• Hydrogel modification reduced peak currents for MB, MB-BSA, and MB-IgG, with diffusivity increasing with mesh size.
• Successful detection of MB-BSA release after hydrogel drying.

Conclusions:

• PEG-DMA hydrogel properties can be tuned by concentration and molecular weight.
• Hydrogel mesh size influences small molecule and protein diffusion, impacting sensor performance.
• Dried PEG-DMA hydrogels show promise as stable reagent reservoirs for biosensing applications.