Preparation and characterization of magnetic PEGDA beads for enhanced construction of hydrogel assembly

Magnetic hydrogel microbeads have wide applications in the fields of biological engineering and regenerative medicine. In the paper, we proposed a new method for fabricating the magnetic hydrogel beads by encapsulating the magnetic resonance imaging (MRI) contrast media inside the polyethylene glycol diacrylate (PEGDA) solution. Then a microfluidic device was prepared for crosslinking the magnetic PEGDA under the ultraviolet (UV) exposure. A thin layer of polydimethylsiloxane (PDMS) was coated on the glass substrate of the microfluidic device to avoid the adhesion of the fabricated magnetic hydrogel beads with the glass substrate. The thickness of the magnetic hydrogel beads can be controlled by the thickness of the microfluidic device and the shape can be adjusted by the shadow mask. In the experiments, magnetic beads with a thickness of 35 μm and a diameter of 100 μm were successfully fabricated. Different types of PEGDA were evaluated for the solubility of MRI with PEGDA. The MRI contrast media mixed with PEGDA 400 solution showed good solubility and no particle aggregation was observed. The fabricated hydrogel beads showed good potential in the application of active drug delivery and enhanced construction of hydrogel assembly for tissue engineering.