A new nanotechnology-based technique could lead to a test for diagnosing the early signs of Alzheimer’s disease. The Bio-Barcode-Assay can recognise ADDL, a protein that accumulates in the brains of sufferers. It is a million times more sensitive than conventional tests and could revolutionise disease detection. In future, it might form the basis not only of a test for Alzheimer’s but also for types of cancer, the human form of mad cow disease and HIV. Details of the technique have been outlined at a one-day conference in London. Doctors currently have no way of diagnosing Alzheimer’s disease in their patients. The disease can only be confirmed after death, by studying brain tissue. “Diagnosis [of Alzheimer’s] is 100% accurate post-mortem. What you want is the ability to detect the marker so you can begin to think about new types of therapies,” said Professor Chad Mirkin, of Northwestern University in Evanston, US. Professor Mirkin and his research group at Northwestern developed the highly sensitive test by manipulating molecules at the nanometre scale (one billionth of a metre).