Three million times smaller than an expectant crowd, these tiny needles of black silicon are nevertheless waiting for something. Surface-enhanced Raman spectroscopy (SERS) is a common technique used to spot harmful substances, looking for tell-tale chemical fingerprints in potentially carcinogenic or even explosive samples. But this is only possible after the mystery molecules have attached to a microscopic platform, or substrate. There’s a problem though, many substrates used in SERS react in some way with the chemicals they grab on to, clouding accurate analysis. Black silicon is inert – it doesn’t react with chemical samples, making it ideal as a substrate. Pictured here using scanning electron microscopy, its crystalline prongs are just waiting to grab onto something dangerous.
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.