Ecoflex-Hydrogel Bilayer Soft Robot for pH-Controlled Drug Protection and Delivery

Conventional anticancer therapies remain limited by inadequate tumor-specific delivery and substantial off-target toxicity. Although hydrogel-based drug delivery systems offer high biocompatibility and tunable release profiles, their clinical translation is often impeded by uncontrolled diffusion and premature drug leakage inherent to their porous networks. Here, we introduce a multifunctional silicone-hydrogel bilayer soft robotic platform designed to achieve precise, stimuli-responsive drug delivery with enhanced retention and spatiotemporal control. Unlike conventional hydrogel-based systems, the proposed platform employs an Ecoflex–hydrogel bilayer architecture in which the elastomeric Ecoflex layer acts as a protective barrier that mechanically confines the hydrogel and suppresses premature drug leakage. The bilayer architecture integrates a hydrophobic silicone layer, which effectively suppresses unintended drug leakage, with a pH-responsive poly( N -isopropylacrylamide-co-acrylic acid) (p(NIPAM-co-AAc)) hydrogel layer that enables on-demand release via reversible swelling-deswelling behavior. Incorporation of magnetic iron(III) oxide (Fe 2 O 3 ) nanoparticles within the silicone matrix further allows remote, non-invasive actuation under external magnetic fields. The platform exhibits excellent thermal stability at physiological temperature (36.5 °C) and demonstrates selective drug release under alkaline conditions representative of the intestinal microenvironment. Repeated pH cycling confirms robust structural integrity and highly reversible actuation over multiple cycles. Collectively, this work establishes the silicone-hydrogel bilayer soft robot as a versatile, magnetically actuated, pH-responsive drug delivery system with significant potential for precision cancer therapy. Thermo- and pH-responsive, magnetically actuated silicone/hydrogel bilayer soft robot for site-specific drug delivery. A bilayer platform combines a hydrophobic Ecoflex silicone barrier with thermo- and pH-responsive p(NIPAM-co-AAc) hydrogel, ensuring secure drug detention under acidic conditions and controlled release in alkaline environments. Embedded Fe2O3 nanoparticles enable remote magnetic locomotion, allowing precise navigation and on-demand drug delivery for targeted cancer therapy. • A bilayer soft robotic design based on Ecoflex/p(NIPAM-co-AAc) is developed for programmable, site-specific drug delivery, integrating magnetic navigation and pH-triggered release. • The p(NIPMA-co-AAc) hydrogel exhibits shear-thinning behavior, pH-responsive swelling, and reversible actuation, enabling controlled shape transformation. • The hydrophobic Ecoflex layer suppresses premature drug leakage while maintaining structural integrity under repeated actuation cycles. • Magnetic Fe 2 O 3 nanoparticles allow remote, non-invasive navigation, and the platform remains biocompatible and mechanically stable under physiological conditions, suitable for gastrointestinal applications.