New immunoassay technique measures extremely low concentrations of small molecules using single-molecule detection
(PHYSorg.com Chemistry)

As medical science has come to understand that the human body is controlled on the molecular level by various proteins, hormones, drugs, and other substances, technologies have developed to detect levels of these molecules in order to monitor health and diagnose disease. However, many of these molecules are so small that they cannot be detected by the most widely available analysis techniques, leaving questions about crucial substances like amino acids, sugars, and lipids largely unanswered.