Self-assembling nanodevices can move and change shape on demand

Posted by Emma Woollacott

A Harvard-led team has created nanodevices made of DNA that self-assemble and can be programmed to move and change shape. They're perfect for medical applications, says the team, because DNA is biocompatible and biodegradable.

Each device is made of a circular, single-stranded DNA molecule that, when mixed together with many short pieces of complementary DNA, self-assembles into a predetermined 3D structure.

Double helices fold up into larger, rigid linear struts that are connected by single-stranded DNA. These single strands pull the struts up into a 3D form.

"These little Swiss Army knives can help us make all kinds of things that could be useful for advanced drug delivery and regenerative medicine," said lead investigator William Shih, Harvard Wyss Institute core faculty member and associate professor of biological chemistry and molecular pharmacology at HMS and Dana-Farber Cancer Institute.

"We also have a handy biological DNA Xerox machine that nature evolved for us, making these devices easy to manufacture."

"This new self-assembly based nanofabrication technology could lead to nanoscale medical devices and drug delivery systems, such as virus mimics that introduce drugs directly into diseased cells," said co-investigator and Wyss Institute director Don Ingber.

A nanodevice that can spring open in response to a chemical or mechanical signal could ensure that drugs are released when and where desired. Similar devices could even one day reprogram human stem cells to regenerate injured organs.

This new capability "is a welcome element in the structural DNA nanotechnology toolbox," said Ned Seeman, professor of chemistry at New York University.