A nanoprinter for cheaper diagnostics

Using strands of DNA as movable type, scientists have created a miniaturized printing technique for mass-producing medical-diagnostic chips.

In the technique, developed by Francesco Stellacci of the Massachusetts Institute of Technology (MIT) and his colleagues, scientists attach thousands or millions of customized DNA strands to a gold chip in a specific pattern. This becomes the master chip.

To mass-produce DNA chips, the researchers dunk the master into a solution containing sequences of DNA that are complementary to the strands on the master and are capped with a chemical that binds to gold. After the complementary strands bind to their DNA cohorts on the master, their ends adhere to a second gold surface gently pressed against the chip. Heating the entire complex causes the paired DNA strands to separate, yielding a new chip and liberating the master to be used again.

Called supramolecular nanostamping, the technique holds promise as an inexpensive way of churning out large numbers of diagnostic chips. A single chip could hold hundreds of thousands of snippets of DNA, each with a different sequence. By passing a tiny blood sample over the chip, doctors could screen for specific genes and patterns of gene activity underlying various genetic diseases and cancers.

Stellacci and his colleagues at MIT and Virginia Commonwealth University in Richmond describe the technique in the June Nano Letters.

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