The modification of erythrocyte membrane properties provides a new tool towards improved drug delivery and biomedical applications. The fabrication of hybrid erythrocyte liposomes is presented by doping red blood cell membranes with synthetic lipid molecules of different classes (PC, PS, PG) and different degrees of saturation (14:0, 16:0–18:1). The respective solubility limits are determined, and material properties of the hybrid liposomes are studied by a combination of X‐ray diffraction, epi‐fluorescent microscopy, dynamic light scattering (DLS), Zeta potential, UV‐vis spectroscopy, and Molecular Dynamics (MD) simulations. Membrane thickness and lipid orientation can be tuned through the addition of phosphatidylcholine lipids. The hybrid membranes can be fluorescently labelled by incorporating Texas‐red DHPE, and their charge modified by incorporating phosphatidylserine and phosphatidylglycerol. By using fluorescein labeled dextran as an example, it is demonstrated that small molecules can be encapsulated into these hybrid liposomes.

We report the preparation and mechanical properties of highly swellable, spherical polymer microgels synthesized by precipitation copolymerization of divinylbenzene‐55 (DVB), 4‐methylstyrene (4MS), and maleic anhydride (MA) at different cross‐linker contents, in a range of methylethylketone (MEK) and heptane solvent mixtures. Microgels were characterized by optical and confocal microscopy, and their mechanical properties tested using real‐time deformability cytometry (RT‐DC), a technique developed to analyze cell properties by measuring deformation under shear stress. Hydrolysis of anhydride groups gave microgels with diameters ranging from 10 to 22 μm when swollen in saline, depending on vol% MEK and cross‐linker loading. Young's moduli of the microgels could be tuned from 0.8 to 10 kPa by adjusting cross‐linker content and MEK/heptane solvent composition, showing an inverse relationship between the effects of vol% MEK and %DVB on microgel properties. These microgels also show strain‐stiffening in response to increasing shear stresses. Extension of the RT‐DC method to the study of polymer colloids thus enables high‐throughput analysis of microgels with tunable mechanical characteristics.

In article number 1900185, Maikel C. Rheinstädter and co‐workers prepare hybrid red blood cell liposomes with tunable membrane properties (e.g. morphology, charge, mechanical properties) by modifying red blood cell membranes with synthetic lipids of different classes. By encapsulating small molecules, the perfect carriers for targeted drug delivery are developed, which minimize immune reactions while circulating in the blood stream for extended periods of time.

The synthesis and properties of micron-sized particles by precipitation polymerization of maleic anhydride (MAn), styrene (Sty), 4-methylstyrene (4MS), and divinylbenzene (DVB-55) in methylethylketone (MEK)/heptane cosolvent mixtures are described. Particles were narrowly dispersed with diameters varying as a function of reaction solvent, cross-linker type and loading, and 4MS/Sty ratios. Diameters ranged from 1 to 14 μm when swollen in good organic solvents, with the largest sizes observed at low cross-linker loadings and for polymerization solvents containing ≥70 vol % MEK. At constant cross-linker loading and solvency, increasing the 4MS/Sty ratio from 0.1 to 1 more than doubled the particle diameters, illustrating the impact of comonomer composition on particle nucleation. Switching entirely from 4MS to Sty shifted solvency requirements for microgel formation by 10 vol % of the good solvent, MEK. Similarly, replacing DVB-55 with a diacrylate cross-linker restricted microgel formation to lower solvency regimes. Hydrolysis of anhydride groups gave microgels with pH-dependent swelling and volume swelling ratios of up to 40 depending on the degree of cross-linking.