What looks like a ribbon threaded through holes in a frosty surface is actually a tiny nanowire, just one twenty-fifth of the diameter of a human hair, made of DNA and gold. To make it, a liquid containing gold nanoparticles and little circles of DNA is poured over a membrane full of holes (the punctures in the surface), along with a cocktail of chemicals that turn the DNA circles into long strands. As the liquid dries and sinks through the pores it pulls these DNA strands down through the holes, coating them with gold along the way. Once connected, the nanowires can send an electrical signal from one side of the membrane to the other. By tweaking the chemical mixture so it only makes wires in the presence of specific biological substances – such as bacteria or damaged genes – researchers are developing this technology to build miniature biosensors to detect diseases.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.