The glycocalyx surrounds each cell in the human body like a coat. This complex sugar layer plays a key role in the progression of numerous diseases, such as cancer and autoimmune diseases. Researchers at the Max Planck Institute for the Science of Light (MPL) have succeeded for the first time in imaging individual sugars within the glycocalyx at molecular resolution and linking their spatial arrangement to their biological function. The findings, recently published in the journal “Nature Nanotechnology”, open up completely new perspectives for understanding this important cell structure – with far-reaching consequences for diagnosis and therapy.