Magnetically Controlled Polymer Giant Unilamellar Vesicles

Giant unilamellar vesicles (GUVs) are essential tools for mimicking cellular processes such as membrane transport and for applications including sensing or protocell development. While it is often desirable to immobilize GUVs in these contexts, many immobilization approaches are irreversible, or limited in flexibility and scalability. Here, PDMS₂₅-b-PMOXA₁₀-based polymer GUVs equipped with superparamagnetic nanoparticles (SPIONs) that can be manipulated and reversibly immobilized on solid supports by magnetic fields are presented. A scalable double-emulsion microfluidic technique serves to form GUVs and simultaneously encapsulate desired cargos, including proteins, together with SPION clusters. SPION clusters act as "magnetic controllers" for the reversible positioning of the resulting magnetic GUVs (M-GUVs). Systematic optimization of M-GUV production has overcome stability challenges associated with the interaction between hard SPION clusters and soft polymer membranes in the presence of the magnetic field, and M-GUV integrity is preserved when exposed to various stresses (vibrations, temperature, magnetic fields). The M-GUVs allow controlled movement, rearrangement, and immobilization through an external magnetic field, with release upon field removal. The straightforward co-loading of proteins and SPION clusters inside M-GUVs together with the potential insertion of molecules into their membrane open new avenues in various applications such as biosensing, surface-based assays, and environmental remediation.