Enzyme Catalysis To Power Micro/Nanomachines

Abstract

Enzymes play a crucial role in many biological processes which require harnessing and converting free chemical energy into kinetic forces in order to accomplish tasks. Enzymes are considered to be molecular machines, not only because of their capability of energy conversion in biological systems but also because enzymatic catalysis can result in enhanced diffusion of enzymes at a molecular level. Enlightened by nature’s design of biological machinery, researchers have investigated various types of synthetic micro/nanomachines by using enzymatic reactions to achieve self-propulsion of micro/nanoarchitectures. Yet, the mechanism of motion is still under debate in current literature. Versatile proof-of-concept applications of these enzyme-powered micro/nanodevices have been recently demonstrated. In this review, we focus on discussing enzymes not only as stochastic swimmers but also as nanoengines to power self-propelled synthetic motors. We present an overview on different enzyme-powered micro/nanomachines, the current debate on their motion mechanism, methods to provide motion and speed control, and an outlook of the future potentials of this multidisciplinary field.

Medical microbots need better imaging and control

“…For example, they could burn a pollutant in water as fuel, or be used for on-chip chemical and biological sensing. For in vivo uses, they need to co-opt fuels that are present in the body, such as glucose, urea or other physiological fluids 2 . For example, tubular micromotors have been propelled by dissolving zinc in acid in a mouse's stomach 3 .…”

Micro- and nano-motors: the New Generation of Drug Carriers

“…The oxygen bubbles were expelled from one side of the carbon nanotube, inducing its forward motion [61]. From then on, different synthetic structures such as porous Janus nanomotors, [62] rolled-up microtubes [31] and stomatocytes [63,64] have been used to immobilize or carry enzymes which can react with the surrounding environment, leading to self-propulsion of the microand nano-motors via enhanced diffusion or bubble formation [65]. Recently, Sanchez's group reported the use of enzymatic mesoporous nanomotors which move in urease-based media to carry and deliver DOX onto cancer cells in vitro, showing that the drug-loaded nanomotors were more effective in killing cancer cells when they were in presence of urea, compared to passive carriers, due to the motor kinetics and the ammonia production by the catalytic decomposition of urea ( Figure 1D & Table 1) [51].…”

Electric-Field-Guided Precision Manipulation of Catalytic Nanomotors for Cargo Delivery and Powering Nanoelectromechanical Devices

“…[1][2][3][4][5][6][7][8][9] Catalytic micro/nanomotors that convert chemical energy into mechanical motions, are one of the most widely exploited autonomous nanomotors. [10][11][12][13][14][15][16][17][18] Billions of catalytic nanomotors can be facilely fabricated by using a variety of techniques, such as electrodeposition into nanoporous templates and electron beam deposition on monolayer nanospheres. [1][2] They self-propel by harvesting chemical energies from fuels in suspension, such as hydrogen peroxide.…”