Metal–Organic Frameworks in Motion

Abstract

During the last two decades, engineering motion with small-scale matter has received much attention in several areas of research, ranging from supramolecular chemistry and colloidal science to robotics and automation. The numerous discoveries and innovative concepts realised in motile micro-and nanostructures have converged in the field of small-scale swimmers. These manmade micro-and nanomachines can move in fluids by transforming different forms of energy to mechanical motion. Recently, metal-organic frameworks (MOFs), which are crystalline coordination polymers with high porosity, have been proposed as key building blocks in several small-scale swimmer designs. These materials possess the required features for motile micro-and nanodevices, such as high cargo-loading capacity, biodegradability, biocompatibility, and stimuliresponsiveness. In this review, we take a journey through the major breakthroughs and milestones realised in the area of MOF-based small-scale swimmers. First, a brief introduction to the field of small-scale swimmers is provided. Next, we review different strategies that have been reported for imparting motion to MOFs. Finally, we emphasise the incorporation of molecular machines into the MOF's architecture as the means to create highly integrated small-scale swimmers. The strategies and developments explored in this review pave the way towards the use of motile MOFs for a variety of applications in the fields of biomedicine, environmental remediation and on-thefly chemistry.

Lanthanide-Aromatic Iminodiacetate Frameworks with Helical Tubes: Structure, Properties, and Low-Temperature Heat Capacity

“…42 − 44 What is fascinating about them is not only enchanting motifs but also broad applications in the fields of chiral synthesis, optical devices, sensory functions, and drug delivery. 45 − 53 However, 3D helical frameworks with helical tunnels (not straight channel formed by helical chains) are not common to our knowledge.…”

Enzyme-Powered Porous Micromotors Built from a Hierarchical Micro- and Mesoporous UiO-Type Metal–Organic Framework

“…MOFs exhibit very high surface areas, tunable pore sizes and shapes, and adjustable pore-surface functionality, suggesting their potential for myriad applications, including gas-storage, separation, catalysis, contaminant removal, and drug delivery. 18,19 In fact, researchers have used MOFs to build stable and adaptable chassis for micro-and nanomotors, 20,21 in which motion is based on Marangoni effects, [22][23][24][25] magneticallydriven corkscrew locomotion 26,27 or bubble propulsion [28][29][30][31][32][33][34] . For the latter, studies are si far mostly limited to metallic catalytic materials (e.g.…”

Microplastic Removal and Degradation by Mussel‐Inspired Adhesive Magnetic/Enzymatic Microrobots

“…[ 5,6 ] Compared with their static counterparts, motile nano/micromotors powered by chemical fuels. [ 7–10 ] or external sources (e.g., magnetic field, [ 11–13 ] ultrasound wave, [ 14 ] and light [ 15 ] ) exhibit notably higher working efficiency for wastewater treatment due to the vigorous dynamic stirring via performing “chemistry‐on‐the‐fly.” [ 16 ] Although many researchers have confirmed the potential of microrobots for water purification in terms of removal, or degradation of heavy metals, [ 11,17 ] oil, [ 18,19 ] antibiotics, [ 20 ] organic contamination (e.g., biological and chemical warfare agents, [ 21–23 ] nerve agents, [ 24 ] explosives, [ 13,25–27 ] dye, [ 28–31 ] pesticides), sensing, [ 32 ] and microbial contamination, [ 33–36 ] investigations on exploiting nano/microrobots for the effective removal of microplastics are still rare.…”