American scientists from the University of Michigan have developed a method to quickly diagnose lung cancer by blood test. The study was published in the scientific journal Matter. The new method picks up exosomes - tiny particles secreted by cells. They carry proteins, DNA and RNA fragments important for intercellular communication. Healthy cells' exosomes transmit important signals throughout the body, while cancerous exosomes can help tumors spread, preparing tissues to accept new growths before they arrive. In the new study, the team exploited a feature of cancer exosomes that causes proteins on their surfaces to mutate frequently. These changes can be detected during a particle's interaction with circularly polarized light. The scientists created gold nanoparticles shaped like twisted disks that can capture particles with their central cavity. Proteins on the captured exosomes immersed in the cavity can amplify or reduce the intensity of the return signal depending on their shape. Positioned along the tiny channels of the microfluidic chip, the gold cavities captured exosomes from blood plasma and revealed different signatures between samples provided by healthy study participants and lung cancer patients. The microfluidic chips, called CDEXO chips, can distinguish between certain lung cancer mutations, helping doctors make treatment decisions targeting the dominant mutations as they change. According to the authors of the development, the new method of diagnosing lung cancer through blood sampling was 10 times faster and 14 times more sensitive than previous methods. The researchers envision that the CDEXO chip will initially be used in conjunction with traditional diagnostic methods. As confidence in the technology develops, the chip could be used to screen other cancers to improve detection in the early stages.