Refillable Fuel-Loading Microshell Motors for Persistent Motion in a Fuel-Free Environment

Polysaccharide-Based Micro/Nanomotors for Active Ingredient Delivery in Food

Micro/nanomotors (MNMs) are miniature devices that can generate energy through chemical reactions or physical processes, utilizing this energy for movement. By virtue of their small size, self-propulsion, precise positioning within a small range, and ability to access microenvironments, MNMs have been applied in various fields including sensing, biomedical applications, and pollutant adsorption. However, the development of food-grade MNMs and their application in food delivery systems have been scarcely reported. Currently, there are various issues with the decomposition, oxidation, or inability to maintain the activity of some nutrients or bioactive substances, such as the limited application of curcumin (Cur) in food. Compared to traditional delivery systems, MNMs can adjust the transport speed and direction as needed, effectively protecting bioactive substances during delivery and achieving efficient transportation. Therefore, this study utilizes polysaccharides as the substrate, employing a simple, rapid, and pollution-free template method to prepare polysaccharide-based microtubes (PMTs) and polysaccharide-based micro/nanomotors (PMNMs). PMNMs can achieve multifunctional propulsion by modifying ferrosoferric oxide (Fe3O4), platinum (Pt), and glucose oxidase (GOx). Fe-PMNMs and Pt-PMNMs exhibit excellent photothermal conversion performance, showing promise for applications in photothermal therapy. Moreover, PMNMs can effectively deliver curcumin, achieving the effective delivery of nutrients and exerting the anti-inflammatory performance of the system.

Dual-source powered nanomotors coupled with dual-targeting ligands for efficient capture and detection of CTCs in whole blood and in vivo tumor imaging

Circulating tumor cells (CTCs) are important biomarkers in cancer diagnosis. However, the specific labeling of CTCs with high capture efficiency in whole blood remains a problem. Herein, a dual-source-driven nanomotor coupled with dual-targeting ligands (CD@NM) was designed for efficient capture, specific imaging and quantitative detection of CTCs. In both water and biological fluid, CD@NMs moved autonomously under the propulsion of a magnetic field and H2O2 solution, which improved the capture efficiency of CTCs to 97.50 ± 2.38%. More importantly, specific labeling of CTCs was achieved by fluorescence quenching and recovery of fluorescent carbon dots modified on the CD@NMs. As a result, the CD@NMs exhibited efficient CTC capture, specific CTC imaging and recognition in whole blood. CD@NMs were also successfully deployed in the specific imaging of tumor tissues in vivo. On this basis, CD@NMs are expected to provide a new platform for tumor diagnosis both in vitro and in vivo.

Enzyme-powered micro- and nano-motors: key parameters for an application-oriented design

Nature has inspired the creation of artificial micro- and nanomotors that self-propel converting chemical energy into mechanical action. These tiny machines have appeared as promising biomedical tools for treatment and diagnosis and have also been used for environmental, antimicrobial or sensing applications. Among the possible catalytic engines, enzymes have emerged as an alternative to inorganic catalysts due to their biocompatibility and the variety and bioavailability of fuels. Although the field of enzyme-powered micro- and nano-motors has a trajectory of more than a decade, a comprehensive framework on how to rationally design, control and optimize their motion is still missing. With this purpose, herein we performed a thorough bibliographic study on the key parameters governing the propulsion of these enzyme-powered devices, namely the chassis shape, the material composition, the motor size, the enzyme type, the method used to incorporate enzymes, the distribution of the product released, the motion mechanism, the motion media and the technique used for motion detection. In conclusion, from the library of options that each parameter offers there needs to be a rational selection and intelligent design of enzymatic motors based on the specific application envisioned.