Proto-molecular nanotechnology – Programmable Molecular Fabrication of trillions of functionalized carbon nanotubes

New York-based Mattershift has managed to create large-scale carbon nanotube (CNT) membranes that are able to combine and separate individual molecules.

Mattershift designs and manufactures nanotube membranes for carbon-zero fuels, health and performance optimized air and water, and precision medicine. The startup was founded in 2013 to realize the potential of molecular factories, with the ultimate goal of printing matter from the air.

Science Advances – Large-scale polymeric carbon nanotube membranes with sub–1.27-nm pores

Abstract
Mattershift reports the first characterization study of commercial prototype carbon nanotube (CNT) membranes consisting of sub–1.27-nm-diameter CNTs traversing a large-area nonporous polysulfone film. The membranes show rejection of NaCl and MgSO4 at higher ionic strengths than have previously been reported in CNT membranes, and specific size selectivity for analytes with diameters below 1.24 nm. The CNTs used in the membranes were arc discharge nanotubes with inner diameters of 0.67 to 1.27 nm. Water flow through the membranes was 1000 times higher than predicted by Hagen-Poiseuille flow, in agreement with previous CNT membrane studies. Ideal gas selectivity was found to deviate significantly from that predicted by both viscous and Knudsen flow, suggesting that surface diffusion effects may begin to dominate gas selectivity at this size scale.

The most basic building block of a Mattershift Molecular Factory is the Programmable Molecular Gateway. It consists of a carbon nanotube fixed within a flexible polymer sheet and aligned so that both of its ends are open.

The gateways are called “programmable” because a great variety of gates can be added to their openings, allowing them to manipulate molecules in specific ways.

One example is a NEMS gate, which is a gateway with a Nano Electro Mechanical System (NEMS) attached. It’s similar to a Micro Electro Mechanical System (MEMS), like the kind used to create accelerometers in smartphones, for example, but NEMS are much smaller. The one shown above is a gate that can be opened and closed by sending an electrical signal through the nanotube to which it’s attached.

Another example is a catalyst gate. This is a gateway with a catalyst attached to the opening of the nanotube. All molecules passing through the gateway must interact with the catalyst, which may be active or passive, removing or adding electrons, combining or splitting molecular parts.

Protein gates may be used to allow only specific molecules to pass through the gateways, like therapeutically useful antibodies, ions, or anything else protein channels may select for. Protein gates consisting of enzymes may also be used for highly specific catalysis of reactions, like those involved in molecular assembly.

A great many types of gates are possible, and many have already been demonstrated in laboratories around the world

Each sheet is embedded with a large number of gateways to transform and transport molecules. A typical density of gateways is 250 Trillion per square meter of sheet.

By creating a series of gateway sheets that perform different functions — purification, catalysis, separation, concentration, further reactions, and so on, complex chemical synthesis can be achieved in compact, inexpensive devices. These factories may be as small as a shoebox or as large as a warehouse.

The key innovation at Mattershift has been to create an inexpensive and scalable platform for this library of gates. With the ability to deploy Programmable Molecular Gateways at scale, we believe practical molecular factories are now possible