Microrobots facilitate targeted therapy due to their small size, minimal invasiveness, and precise wireless control. A degradable hyperthermia microrobot (DHM) with a 3D helical structure is developed, enabling actively controlled drug delivery, release, and hyperthermia therapy. The microrobot is made of poly(ethylene glycol) diacrylate (PEGDA) and pentaerythritol triacrylate (PETA) and contains magnetic Fe3O4 nanoparticles (MNPs) and 5‐fluorouracil (5‐FU). Its locomotion is remotely and precisely controlled by a rotating magnetic field (RMF) generated by an electromagnetic actuation system. Drug‐free DHMs reduce the viability of cancer cells by elevating the temperature under an alternating magnetic field (AMF), a hyperthermic effect. 5‐FU is released from the proposed DHMs in normal‐, high‐burst‐, and constant‐release modes, controlled by the AMF. Finally, actively controlled drug release from the DHMs in normal‐ and high‐burst‐release mode results in a reduction in cell viability. The reduction in cell viability is of greater magnitude in high‐burst‐ than in normal‐release mode. In summary, biodegradable DHMs have potential for actively controlled drug release and hyperthermia therapy.

Microrobots for targeted drug delivery are of great interest due to their minimal invasiveness and wireless controllability. Here, a magnetically driven porous degradable microrobot (PDM) is reported that consists of a 3D printed helical soft polymeric chassis made of a poly(ethylene glycol) diacrylate and pentaerythritol triacrylate matrix containing magnetite nanoparticles and the anticancer drug 5‐fluorouracil (5‐FU). The encapsulated Fe3O4 nanoparticles render the PDM a precise wireless magnetic actuation by means of rotating magnetic fields (RMFs). The increased surface area of the porous PDM facilitates the acoustically induced drug release due to a higher response to the acoustic energy. The drug release profile from the PDM can be selected on command from three different modes, referred to herein as natural, burst, and constant, by differentiating the ultrasound exposure condition. Finally, in vitro test results reveal different therapeutic results for each release mode. The observed great reduction of cancer cell viability in the burst‐ and constant‐release modes confirms that ultrasound with the proposed PDM can enhance the therapeutic effect by increasing drug concentration and sonoporation.

A needle‐type microrobot (MR) for targeted drug delivery is developed to stably deliver drugs to a target microtissue (MT) for a given period time without the need for an external force after affixing. The MRs are fabricatedby 3D laser lithography and nickel (Ni)/titanium oxide (TiO2) layers are coated by physical vapor deposition. The translational velocity of the MR is 714 µm s−1 at 20 mT and affixed to the target MT under the control of a rotating magnetic field. The manipulability of the MR is shown by using both manual and automatic controls. Finally, drug release from the paclitaxel‐loaded MR is characterized to determine the efficiency of targeted drug delivery. This study demonstrates the utility of the proposed needle‐type MR for targeted drug delivery to MT with various flow rates in vitro physiological fluidic environments.

In article number 1901697 by Hongsoo Choi and co‐workers, a drug‐loaded micro‐robot can be attached to a target micro‐tissue by swimming in a corkscrew motion with magnetic torque under a rotating magnetic field. The needle‐type micro‐robot has the potential to improve targeted drug delivery to a micro‐tissue in vitro in physiological fluid environments.

Precise packaging of nanoliter amounts of liquid in a microsystem is important for many biomedical applications. However, existing liquid encapsulation technologies have limitations in terms of liquid waste, evaporation, trapped bubbles, and liquid degradation. In this study, multiple additive manufacturing techniques for nanoliter liquid packaging in bioresorbable microsystems is used. Two‐photon photolithography is used for bioresorbable reservoir fabrication, while inkjet printing (IJP) is used for precise nanoliter liquid packaging. Dual IJP allows for micro‐reservoirs to be filled with precise amounts of drug solution and subsequently and rapidly sealed with a layer of lipids mixed with Fe3O4 nanoparticles. Combining these two printing techniques can overcome the previous limitations of liquid encapsulation technologies. To demonstrate the relevance of this technique, a wirelessly activated, bioresorbable multi‐reservoir microcapsule that can be used for controlled drug delivery is presented. The microcapsules and their content are shown to be stable during fabrication, storage, and operation. Multiple cargo release events are triggered independently by the local melting of the sealing layer, resulting from magnetically induced Fe3O4 nanoparticle heating. The operation of the capsule is demonstrated in tissue phantoms and in vitro cell cultures.