NMR spectroscopy of a single mammalian embryo

Abstract

The resolving power, chemical sensitivity and non-invasive nature of NMR has made it an established technique for in vivo studies of large organisms both for research and clinical applications. These features would clearly be beneficial at the nanoliter scale (nL), typical of early development of mammalian embryos, microtissues and organoids, the scale where the building blocks of complex organisms could be observed. However, the handling of such small samples (about 100 micrometers) and sensitivity issues have prevented the widespread adoption of NMR. Recently we have shown how these limitations can be overcome with ultra-compact single-chip probes. In this article we show that such probes have sufficient sensitivity to detect and resolve NMR signals from individual bovine pre-implantation embryos. In less than 1 hour these spherical samples of just 130-190 micrometers produce distinct spectral peaks, largely originating from lipids contained inside them. We further observe how the spectral features, namely the peak intensities, vary from one sample to another despite their optical and morphological similarities.