Adoptive cell transfers have emerged as a disruptive approach to treat disease in a manner that is more specific than using small-molecule drugs; however, unlike traditional drugs, cells are living entities that can alter their function in response to environmental cues. In the present study, we report an engineered particle referred to as a “backpack” that can robustly adhere to macrophage surfaces and regulate cellular phenotypes in vivo. Backpacks evade phagocytosis for several days and release cytokines to continuously guide the polarization of macrophages toward antitumor phenotypes. We demonstrate that these antitumor phenotypes are durable, even in the strongly immunosuppressive environment of a murine breast cancer model. Conserved phenotypes led to reduced metastatic burdens and slowed tumor growths compared with those of mice treated with an equal dose of macrophages with free cytokine. Overall, these studies highlight a new pathway to control and maintain phenotypes of adoptive cellular immunotherapies.

transition. We fabricated the conductive fibers by injecting a liquid metal, gallium, into stretchable hollow fibers formed by melt-spinning a commercial thermoplastic elastomer. The ability to change the core of the fiber from solid (with a modulus of a metal) to a liquid (with a viscosity near water) allows for dramatic changes in mechanical properties as well as the ability to have shape memory effects. Although the mechanism differs, this effect is similar to shape memory polymers (SMPs), [1][2][3][4][5][6][7][8][9][10] which are fascinating materials that can be programmed to store and recover elastic energy in response to external stimuli. SMPs can be deformed at elevated temperature and then cooled to retain their temporary shape. Heating the polymer again to the elevated temperature allows the stored strain to relax back to the original, predeformed shape. The use of metallic cores as a mechanism to retain elastic fibers in a temporary shape has several advantages relative to conventional shape memory polymers: Shape Memory Fibers

The inherent compliance of soft robots often makes it difficult for them to exert forces on surrounding surfaces or withstand mechanical loading. Controlled stiffness is a solution to empower soft robots with the ability to apply large forces on their environments and sustain external loads without deformations. Herein, a compact, soft actuator composed of a shared electrode used for both electrostatic actuation and variable stiffness is described. The device operates as a dielectric elastomer actuator, while variable stiffness is provided by a shared electrode made of gallium. The fabricated actuator, namely variable stiffness dielectric elastomer actuator (VSDEA), has a compact and lightweight structure with a thickness of 930 μm and a mass of 0.7 g. It exhibits a stiffness change of 183×, a bending angle of 31°, and a blocked force of 0.65 mN. Thanks to the lightweight feature, the stiffness change per mass of the actuator (261× g−1) is 2.6 times higher than that of the other type of VSDEA that has no shared electrode.

Semicrystalline polymeric materials possessing extraordinary mechanical properties were rapidly fabricated using light from low viscosity liquids at room temperature.