In Vivo Sampling: A Promising Technique for Detecting and Profiling Endogenous Substances in Living Systems

Endogenous substances, naturally occurring in living organisms, are critical components with physiological and biological functions. Discovery and quantitative measurement of endogenous substances in living biotas are important for food analysis, crop cultivation, and quality assessment. Low or non-invasive in vivo sampling techniques offer the advantages of minimal perturbation to the investigated system and potentially obtain more accurate feedback compared to in vitro sampling. In this perspective, we summarize the up-to-date progress in the development of microdialysis and solid-phase microextraction as valuable tools for in vivo sampling of endogenous substances in food and agriculture chemistry. We discuss their feasibility for on-site and real-time in vivo monitoring and highlight the prospects in searching for highly specific coatings, miniaturized sampling devices, and instruments that well meet the trend for high-efficient and high-throughput analyses.