Synthetic DNA nanopores for direct molecular transmission between lipid vesicles.

Lipid vesicles hold potential as artificial cells in bottom-up synthetic biology, and as tools in drug delivery and biosensing. Transmitting molecular signals is a key function for vesicle-based systems. One strategy to achieve this function is by releasing molecular signals from vesicles through nanopores. Nevertheless, in this strategy, an excess of molecular signals may be required to reach the targets, due to the dispersion of the signals during diffusion. The key to achieving the efficient utilization of signals is to shorten the distance between the sender vesicle and the target. Here, we present a pair of DNA nanopores that can connect and form a direct molecular pathway between vesicles. The nanopores are self-assembled from nine single DNA strands, including six 14-nucleotide single-stranded overhangs as sticky-end segments, enabling them to bind with each other. Incorporating nanopores shortens the distance between different populations of vesicles, allowing less diffusion of molecules into bulk solution. To further reduce the loss of molecules, a DNA nanocap is added to one of the nanopore's openings. The nanocap can be removed through the toehold-mediated DNA strand displacement when the nanopore meets its counterpart. Our DNA nanopores provide a novel molecular transmission tool to lipid vesicles-based systems.

Lipid vesicle-based molecular robots.

A molecular robot, which is a system comprised of one or more molecular machines and computers, can execute sophisticated tasks in many fields that span from nanomedicine to green nanotechnology. The core parts of molecular robots are fairly consistent from system to system and always include (i) a body to encapsulate molecular machines, (ii) sensors to capture signals, (iii) computers to make decisions, and (iv) actuators to perform tasks. This review aims to provide an overview of approaches and considerations to develop molecular robots. We first introduce the basic technologies required for constructing the core parts of molecular robots, describe the recent progress towards achieving higher functionality, and subsequently discuss the current challenges and outlook. We also highlight the applications of molecular robots in sensing biomarkers, signal communications with living cells, and conversion of energy. Although molecular robots are still in their infancy, they will unquestionably initiate massive change in biomedical and environmental technology in the not too distant future.