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.
A silicon carbonitride (SICN) ceramic microrobot, biocompatible and magnetically activable, is developed for the delivery of viable cells to defective tissue by sequential steps of microstructuring, magnetization, and cell loading. The ceramic carrier of porous cylindrical framework is fabricated by 3D laser lithography using a photocurable preceramic polymer, chemically modified polyvinylsilazane, and subsequent pyrolysis at 600 °C under an inert atmosphere. Magnetic nanoparticles (MNP) are integrated into the surface‐modified ceramic carrier by thiol‐ene click reaction. Finally, the microrobot is loaded with fibroblast cells, which can be guided by a rotating external magnetic field. The proposed ceramic microrobot is mechanically durable, adequately controllable with external magnetic field, and quite compatible with mammalian cells.
Robotic magnetic manipulation systems offer a wide range of potential benefits in medical fields, such as precise and selective manipulation of magnetically responsive instruments in difficult‐to‐reach vessels and tissues. However, more preclinical/clinical studies are necessary before robotic magnetic interventional systems can be widely adopted. In this study, a clinically translatable, electromagnetically controllable microrobotic interventional system (ECMIS) that assists a physician in remotely manipulating and controlling microdiameter guidewires in real time, is reported. The ECMIS comprises a microrobotic guidewire capable of active magnetic steering under low‐strength magnetic fields, a human‐scale electromagnetic actuation (EMA) system, a biplane X‐ray imaging system, and a remote guidewire/catheter advancer unit. The proposed ECMIS demonstrates targeted real‐time cardiovascular interventions in vascular phantoms through precise and rapid control of the microrobotic guidewire under EMA. Further, the potential clinical effectiveness of the ECMIS for real‐time cardiovascular interventions is investigated through preclinical studies in coronary, iliac, and renal arteries of swine models in vivo, where the magnetic steering of the microrobotic guidewire and control of other ECMIS modules are teleoperated by operators in a separate control booth with X‐ray shielding. The proposed ECMIS can help medical physicians optimally manipulate interventional devices such as guidewires under minimal radiation exposure.
CdxHg1−xSe/HgS/CdyZn1−yS core/multi‐shell quantum dots (QDs) exhibiting bright tissue‐penetrating shortwave infrared (SWIR; 1000–1700 nm) photoluminescence (PL) are engineered. The new structure consists of a quasi‐type‐II CdxHg1−xSe/HgS core/inner shell domain creating luminescent bandgap tunable across SWIR window and a wide‐bandgap CdyZn1−yS outer shell boosting the PL quantum yield (QY). This compositional sequence also facilitates uniform and coherent shell growth by minimizing interfacial lattice mismatches, resulting in high QYs in both organic (40–80%) and aqueous (20–70%) solvents with maximum QYs of 87 and 73%, respectively, which are comparable to those of brightest visible‐to‐near infrared QDs. Moreover, they maintain bright PL in a photocurable resin (QY 40%, peak wavelength ≈ 1300 nm), enabling the fabrication of SWIR‐luminescent composites of diverse morphology and concentration. These composites are used to localize controlled amounts of SWIR QDs inside artificial (Intralipid) and porcine tissues and quantitatively evaluate the applicability as luminescent probes for deep‐tissue imaging.
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