In vivo bioprinting has recently emerged as a direct fabrication technique to create artificial tissues and medical devices on target sites within the body, enabling advanced clinical strategies. However, existing in vivo bioprinting methods are often limited to applications near the skin or require open surgery for printing on internal organs. Here, we report a ferromagnetic soft catheter robot (FSCR) system capable of in situ computer-controlled bioprinting in a minimally invasive manner based on magnetic actuation. The FSCR is designed by dispersing ferromagnetic particles in a fiber-reinforced polymer matrix. This design results in stable ink extrusion and allows for printing various materials with different rheological properties and functionalities. A superimposed magnetic field drives the FSCR to achieve digitally controlled printing with high accuracy. We demonstrate printing multiple patterns on planar surfaces, and considering the non-planar surface of natural organs, we then develop an in situ printing strategy for curved surfaces and demonstrate minimally invasive in vivo bioprinting of hydrogels in a rat model. Our catheter robot will permit intelligent and minimally invasive bio-fabrication.

Cerebral aneurysms and brain tumors are leading life-threatening diseases worldwide. By deliberately occluding the target lesion to reduce the blood supply, embolization has been widely used clinically to treat cerebral aneurysms and brain tumors. Conventional embolization is usually performed by threading a catheter through blood vessels to the target lesion, which is often limited by the poor steerability of the catheter in complex neurovascular networks, especially in submillimeter regions. Here, we propose magnetic soft microfiberbots with high steerability, reliable maneuverability, and multimodal shape reconfigurability to perform robotic embolization in submillimeter regions via a remote, untethered, and magnetically controllable manner. Magnetic soft microfiberbots were fabricated by thermal drawing magnetic soft composite into microfibers, followed by magnetizing and molding procedures to endow a helical magnetic polarity. By controlling magnetic fields, magnetic soft microfiberbots exhibit reversible elongated/aggregated shape morphing and helical propulsion in flow conditions, allowing for controllable navigation through complex vasculature and robotic embolization in submillimeter regions. We performed in vitro embolization of aneurysm and tumor in neurovascular phantoms and in vivo embolization of a rabbit femoral artery model under real-time fluoroscopy. These studies demonstrate the potential clinical value of our work, paving the way for a robotic embolization scheme in robotic settings.

One-dimensional all-inorganic halide perovskites have emerged as one of the most prominent materials in the application of optoelectronic devices due to their remarkable properties such as a low number of defects, morphological anisotropy, mechanical flexibility and fast charge transfer capability. Particularly, cubic (α) phase CsPbI₃ has the narrowest band gap of 1.73 eV among all-inorganic lead halide perovskites, exhibiting the greatest potential in solar cell applications. However, the direct synthesis of room temperature stabilized α-CsPbI₃ nanowires is challenging and remains unfulfilled because the synthesis reaction usually involves a phase change process, resulting in an undesired orthorhombic (δ) phase with a wider bandgap of 2.82 eV. Here, we report a low-temperature approach to directly synthesize highly stabilized α-CsPbI₃ nanowires. Low reaction temperature, capping ligand protection, and extended growth time are employed to successfully grow α-CsPbI₃ nanowires. The as-synthesized α-CsPbI₃ nanowires are 10–20 μm in length and 5–80 nm in diameter. The X-ray diffraction (XRD), photoluminescence (PL), and UV-vis absorption results verify that these cubic phase nanowires maintain excellent stability at room temperature for 90 days. The CsPbI₃ nanowires show a PL peak located at around 685 nm and the UV-vis absorption spectrum further reveals that the band gap is about 1.77 eV. The excellent optical properties of the phase-stable CsPbI₃ nanowires offer great potential in the field of optoelectronic devices.