Microfluidic Based In Situ Synthesis of Magneto-Responsive Microcarrier Hydrogel Bead and its Cell Seeding Applications

This study presents an approach to the synthesis of nanocomposite magnetic hydrogel microbeads using a microfluidic-assisted droplet method followed by in situ gelation in a heated oil column. The beads were fabricated from a semi-interpenetrating polymer network (semi-IPN) comprising gelatin, and vinylic monomers, with incorporation of iron oxide nanoparticles (Fe 3 O 4 ) synthesized via coprecipitation. The unique combination of pressure-mediated bead formation and controlled gelation kinetics enabled tunable porosity, as validated through SEM and pore size distribution analysis, where increased oil column height yielded narrower pore distributions due to enhanced gelation. Magnetic characterization confirmed strong superparamagnetic behavior, while FTIR and XRD analyses verified successful chemical integration of the polymeric and nanoparticle components. Rheological studies revealed enhanced elasticity and network strength in nanoparticle-loaded hydrogels, and swelling/deswelling tests, fitted with first-order and exponential decay models, demonstrated reversible, magnetically tunable water uptake. Furthermore, in vitro cell culture studies showed excellent cell attachment and proliferation on the bead surface, facilitated by the porous, wrinkled morphology. Collectively, these multifunctional beads exhibit significant promise for applications in cell delivery, magnetically guided therapies, and responsive tissue engineering platforms.