Nano-vaccine cancer treatment research. Scanning electron micrograph (SEM) of a dendritic cell (part of the immune system) being presented with nano-vaccines (yellow discs). These are porous silicon particle discs loaded with immune-stimulating molecules and tumour antigens. The now-activated dendritic cells are then injected back into the host to stimulate an anti-tumour response to treat cancers. This work was carried out by researchers from the Texas Center for Cancer Nanomedicine (TCCN), USA. Image produced in 2012.