A simplified template-assisted layering approach for preparing catalytic conical tube microjet engines based on sequential deposition of platinum and gold on an etched silver wire template followed by dicing and dissolution of the template is described. The method allows detailed control over the tube parameters and hence upon the performance of the microengine. The recoiling bubble propulsion mechanism of the tubular microengine, associated with the ejection of internally generated oxygen microbubbles, addresses the ionic-strength limitation of catalytic nanowire motors and leads to a salt-independent movement. Similar rates of bubble generation and motor speeds are observed in salt-free and salt-rich media (at elevated ionic-strength environments as high as 1 M NaCl). Plating of an intermediate nickel layer facilitates a magnetically guided motion as well as the pickup and transport of large (magnetic) "cargo". Surfactant addition is shown to decrease the surface tension and offer a more frequent formation of dense smaller bubbles. The new and improved motor capabilities along with the simple preparation route hold great promise for using catalytic micromotors in diverse and important applications.

An electrochemically-controlled movement of catalytic nanomotors, including a cyclic 'on/off' activation of the nanomotor motion and a fine speed control, is illustrated.

The addition of ATP under dissipative conditions to a complex mixture causes the transient upregulation of hydrazone-bond formation.

No abstract

Precise control over specific functions in the time domain is ubiquitous in biological systems. Here, we demonstrate time-gated fluoroscence signalling under dissipative condition exploiting an ATP-fueled self-assembly process. A temporal...