lifedetection

Lifedetection refers to the identification or confirmation of living organisms or biological activity in a sample, environment, or signal. It spans disciplines such as microbiology, medicine, environmental science, and astrobiology. The goal is to determine presence, abundance, viability, and, when possible, metabolic activity or ecological role.

Methods include molecular techniques like DNA/RNA sequencing and polymerase chain reaction (PCR), including quantitative PCR, which identify genetic material from organisms. Immunoassays detect specific proteins or antigens. Microscopy visualizes cells and structures. Culture-based methods recover living organisms. Metabolic indicators such as ATP assays, respiration measurements, or gas production signal activity. Biosensors—optical, electrochemical, or aptamer-based—provide real-time detection. Environmental DNA (eDNA) sampling detects traces of DNA shed by organisms into the environment. Spectroscopic approaches and imaging techniques can infer biosignatures, and in space missions, remote sensing and rover-based instruments are used to search for potential signs of life.

Applications include clinical lifedetection for pathogen identification and viability assessment; environmental monitoring of water quality, soil microbiology, and ecosystem health; industrial bioprocess monitoring; and astrobiology, which seeks biosignatures and, where relevant, technosignatures on other worlds, while emphasizing rigorous controls to avoid contamination and misinterpretation.

Challenges involve achieving sufficient sensitivity and specificity, avoiding contamination, distinguishing living signals from abiotic processes, interpreting ambiguous data, and addressing regulatory, ethical, and safety considerations in field or space contexts.

See also biosignature, astrobiology, microbiology, biosensor.