Scientists at the CSIC and at the IRB Barcelona –based in the Parc Científic de Barcelona–have obtained a nanosensor based on small DNA fragments, using an advanced technique known as DNA origami. It has the size of 100 nanometres: it is a thousand times smaller than a bacteria and it would be necessary millions of sensors like this to fill the hole in a sewing needle.

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The new molecular sensor can detect the activity of the human enzyme hAGT. This is interesting for anticancer research, as this enzyme is one of the targets for new drugs and it is one of the markers that can predict the success of a new treatment. It is, also, a substantial step in the control of DNA as building material for biomedical devices at the nanometric scale.

The work, published in the magazine Angewandte Chemie (doi: 10.1002/anie.201301293), has been developed by the group of Nucleic Acids Chemistry at the Institut de Química Avançada de Catalunya (IQAC-CSIC). The main author is Carmen Fàbrega, who is working in the same group but assigned to the IRB Barcelona.

In the DNA origami technique -named after the traditional oriental art of folding paper to obtain figures- a long chain of DNA is naturally folded with small DNA segments (oligonucleotides) which work as staples, until the wanted structure is obtained.

The structure, which can have different shapes, can be used as a template to place proteins, nanoparticles, enzymes, nanowires or any other functional molecule following a predetermined pattern. The DNA has other advantages: it is rigid at the nanometric scale, it has an extraordinarily small size and an almost infinite possibility of combinations.

“In our work”, explains Ramon Eritja, leader of the Nuclei Acids Chemistry group, “we have used a single strand of viral DNA and 250 oligonucleotides ‘staples’ with which we did fold the DNA until we got a flat structure, with a rectangular shape”.

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