Acoustically‐Propelled Rodlike Liquid Metal Colloidal Motors

Abstract

We report an acoustically‐propelled rodlike liquid metal eutectic gallium‐indium alloy (EGaIn) colloidal motor capable of actively seeking and internalizing into cancer cells. These rod‐shaped EGaIn colloidal motors with a length of 1 μm and a diameter of 200 nm are prepared by a simple sonication crushing method, which is demonstrated to be a core‐shell structure with a 30 nm GaOOH shell and zero‐valent liquid core. A wide spectrum range of light absorbance is demonstrated by using UV‐vis‐NIR spectroscopy and confocal laser scanning microscopy with excitation wavelengths of 488 nm, 543 nm, and 633 nm. Upon exposure to the acoustic field, the rodlike EGaIn colloidal motors can autonomously move at a speed of up to 34.5 μm s−1 without addition of any chemical fuels. The speed of motion is also able to be modulated by adjusting the acoustic voltage. Furthermore, these rodlike EGaIn colloidal motors could actively target and internalize into cancer cells which could be real‐time monitored due to their photoluminance feature. Such rodlike liquid metal colloidal motors have promising applications in biomedical fields.

Using H2O2 as a green oxidant to produce fluorescent GaOOH nanomaterials from a liquid metal

“…Fluorescence imaging is widely used for in vitro and in vivo studies in a wide range of academic, industrial, and medical fields and can in principle be used in real-time to monitor drug transit and accumulation, cell growth, and cell function. 12 As a result, fluorescence imaging has emerged as a viable approach for enhanced disease detection, diagnosis, and identification of surgical effectiveness. 13 However, many of the currently used fluorescent nanoparticles and dyes in the biomedical field still have some disadvantages like poor photostability and lack of biocompatibility.…”

Liquid Metal Swimming Nanorobots

“…The rodlike EGaIn swimming nanorobots had a similar motion mode and ability to penetrate cancer cells, and results show that a large amount of nanorobots would penetrate the cancer cells. 36,40 The application of liquid metal swimming nanorobots to kill bacteria had a special effect. The trivalent gallium cation itself is a kind of antibacterial drug with good performance, which can block the metabolism of bacteria.…”

“…Liquid metal swimming nanorobots had their autofluorescence signal under irradiation, so they could be applied in biomedical applications without additional fluorescent labeling. 40 Surface modification helped liquid metal swimming nanorobots get new functions, such as gallium liquid metal nanorobots were camouflaged by leukocyte membranes, inheriting the antibiofouling ability and cancer cell recognizability of the leukocyte. When moving in biofluids in vitro, the needlelike Ga swimming nanorobots with leukocyte membrane camouflaging had a higher diffusion coefficient.…”

Powering and Fabrication of Small-Scale Robotics Systems

“…4(G). He's group has recently reported the acoustic propulsion of liquid-alloy colloidal nanorods [56]. Interestingly, the 1-µm nanorods were fabricated by means of acoustic crushing of the liquid metal in a fluid.…”