Applications of Nano/Micromotors for Treatment and Diagnosis in Biological Lumens

Abstract

Natural biological lumens in the human body, such as blood vessels and the gastrointestinal tract, are important to the delivery of materials. Depending on the anatomic features of these biological lumens, the invention of nano/micromotors could automatically locomote targeted sites for disease treatment and diagnosis. These nano/micromotors are designed to utilize chemical, physical, or even hybrid power in self-propulsion or propulsion by external forces. In this review, the research progress of nano/micromotors is summarized with regard to treatment and diagnosis in different biological lumens. Challenges to the development of nano/micromotors more suitable for specific biological lumens are discussed, and the overlooked biological lumens are indicated for further studies.

Nano/Micromotors for Cancer Diagnosis and Therapy: Innovative Designs to Improve Biocompatibility

“…Thus, it is necessary to use a microswarm with cooperation behavior. Another medical imaging technology, positron emission tomography (PET), has also been used to track microswarms, in which short-lived radioactive substances, including 124 I on gold nanoparticles or 18 F-labeled urease, were labeled on nanomotors with an enzyme-based engine that showed swarm behavior. During in vivo experiments, the radio-labeled nanomotors underwent positive beta decay and emitted positrons to further interact with ordinary electrons, followed by particle annihilation, γ-ray emission, and, finally, ray detection.…”

“…Table 1 provides some typical examples of the use of biocompatible energy for nano/micromotor propulsion. showing 18 F-and 124 I-radio-labeled nanomotors that can be tracked by positron emission tomography (PET). Adapted from [134] with permission, copyright American Association for the Advancement of Science, Washington, DC, USA, 2023.…”

“…However, biotoxicity remains a challenge that restricts them from moving from the laboratory to clinical applications. These include (a) The toxicology of nano/micromotor components (for instance, by assessing cell viability, previous research reported that Mg/Pt Janus micromotors show a concentration-dependent toxic trend) [ 13 ]; (b) The generation of harmful byproducts [ 14 ]; (c) The use of toxic fuels at high concentrations [ 15 ]; and (d) The immune response caused by nondegradable components and the use of sperm derived from other species [ 16 , 17 , 18 ]. Recent advances show the great efforts made by researchers to improve the biocompatibility of nano/micromotors.…”

“…Adapted from [133], permission not needed for this open-access article, copyright American Association for the Advancement of Science, Washington, DC, USA, 2023. (B) Schematic illustration showing18 F-and 124 I-radio-labeled nanomotors that can be tracked by positron emission tomography (PET). Adapted from[134] with permission, copyright American Association for the Advancement of Science, Washington, DC, USA, 2023.…”

Applications and Future Prospects of Micro/Nanorobots Utilizing Diverse Biological Carriers

“…For instance, chemical fuel-driven motors might not be suitable for microvascular applications, as exhaust gases can cause embolization in small blood vessels in the lungs or brain. As the micromotor travels deeper into the body, external power decreases, limiting its ability to move farther [ 24 ]. To overcome these challenges, researchers have turned to hybrid MNRs and bio-motors, which are highly biocompatible and specific [ 25 ].…”