Microscopic metal boxes that hold a few nanolitres of liquid each have been developed by US researchers. They say the tiny containers could someday be used for precision chemistry or even drug delivery inside the body.
The tiny boxes are made from flat templates that self-assemble due to liquid surface tension during the production process. Once constructed, they can be also moved around remotely using magnetic fields. This means they could carry small chemical samples around or possibly even deliver drugs within the human body, the researchers say.
"We have shown that we can bring two or more of them together to allow the chemicals they hold to react," explains researcher David Gracias, a chemical engineer at Johns Hopkins University, US.
The sides of each box are made using an established manufacturing method called electrodeposition. This involves chemically depositing layers of nickel on top of a polymer-coated silicon wafer and then applying an electric current to bind them together.
They have built nano-containers with capacities ranging from 230 picolitres (trillionths of a litre) to 8 nanolitres (billionths of a litre). The boxes are reconfigurable and an alternative to microfluidic chips.