A new technique for evaluating drug safety can detect stress on cells at earlier stages than conventional methods, which mostly rely on detecting cell death. The new method uses a fluorescent sensor that is turned on in a cell when misfolded proteins begin to aggregate—an early sign of cellular stress. The method can be adapted to detect protein aggregates caused by other toxins, as well as diseases such as Alzheimer’s or Parkinson’s. A paper describing the new method, by a team of researchers at Penn State University, appears in the journal Angewandte Chemie International Edition.