Bioinspired claw-engaged and biolubricated swimming microrobots creating active retention in blood vessels

Abstract

Swimming microrobots guided in the circulation system offer considerable promise in precision medicine but currently suffer from problems such as limited adhesion to blood vessels, intensive blood flow, and immune system clearance—all reducing the targeted interaction. A swimming microrobot design with clawed geometry, a red blood cell (RBC) membrane–camouflaged surface, and magnetically actuated retention is discussed, allowing better navigation and inspired by the tardigrade’s mechanical claw engagement, coupled to an RBC membrane coating, to minimize blood flow impact. Using clinical intravascular optical coherence tomography in vivo, the microrobots’ activity and dynamics in a rabbit jugular vein was monitored, illustrating very effective magnetic propulsion, even against a flow of ~2.1 cm/s, comparable with rabbit blood flow characteristics. The equivalent friction coefficient with magnetically actuated retention is elevated ~24-fold, compared to magnetic microspheres, achieving active retention at 3.2 cm/s, for >36 hours, showing considerable promise across biomedical applications.

High-performance magnetic metal microrobot prepared by a two-photon polymerization and sintering method

“…, red cells), the swimming situation of the Ni-MAR in blood is extraordinarily complicated. 40 This is a simple simulated experiment by actuating the Ni-MAR in moderate-viscosity liquid, without considering the interaction between the Ni-MAR and other blood components. Nevertheless, our result can be a guideline to design and conduct the swimming experiment of microrobots in real blood in the future.…”

Ultrasound-propelled nanomotors for efficient cancer cell ferroptosis

“…15–17 It has many advantages including tiny size, controllable motion, and easy functionalization, thus showing potential for broad applications in many areas, such as environmental governance, biomedicine, and multi-responsive actuators nanofabrication. 18–23 The movement of ultrasound (US)-propelled nanomotors can be controlled using an ultrasonic wireless system. 24,25 This non-contact control method has unique advantages for the practical biological application of nanomotors at the cellular level.…”

Untethered Small-Scale Machines for Microrobotic Manipulation: From Individual and Multiple to Collective Machines

“…The advances in developing USSMs with high manipulation precision and multiple degrees-of-freedom (DoFs) of motion have been recently demonstrated thanks to the development of manipulation mechanisms and the in-depth understanding of fundamental science. Here the USSMs are defined as mobile miniature devices in dimensions from micro/nanometers to millimeter-scale that can perform tasks under wireless control. − This definition is from the view of the microrobotic manipulation system since a moving structure or particle itself cannot be defined as a machine. The mechanically connected manipulators are replaced with USSMs that can be wirelessly actuated by several types of external powers (e.g., magnetic, acoustic, electric fields, and light), − self-generated propulsion, − and hybrid power. , The progress in the untethered system-based microrobotic manipulation has benefited from the distinctive ability of USSMs, such as wireless feedback control and on-demand actuation in complex environments. − …”