The next big wave in imaging technology is terahertz radiation, now probing everything from cells to stars. Rheinisch-Westfälische Technische Hochschule scientists have used terahertz radiation to spot particular sequences of DNA in a sample. This technique is quicker and more accurate than current fluorescent-labelling methods.

To detect changes in the tiny amounts of material that are typically involved in gene-chip analysis, the researchers built guide channels, just a few micrometres wide. These channels usher the terahertz signal to and from a patch of probe DNA. Comparing the signal before and after it passes through the DNA patch revealed the resonances that accompany pairing between probe molecules and their complementary strands in a sample.

Terahertz resonances were different for samples containing fragments of the healthy and mutated gene, reflecting the difference in binding to the probe strands.

Very short pulses of terahertz radiation can yield deeper images of damaged tissues (such as cancers and skin burns) faster and in more detail than can X-rays or ultrasound, according to researchers at the Rensselaer Polytechnic Institute in Troy, New York.