Förster resonance energy transfer (FRET) probes are unique tools in biology, as they allow for a non-destructive monitoring of a certain state of a biomolecule or of an artificial substrate within living cells in real time. FRET substrates indicate their relative cleavage rate and thus the in situ activity of a given enzyme. In contrast to quenched probes or turn-on probes, one of the two separate signals of the FRET probes can be used as internal reference, which makes ratio-imaging and quantitation of cleavage events independent of cellular delivery possible. In this review, we describe the first examples of sphingolipid FRET probes in comparison to different alternative probes. Finally, we give an outlook on future probes and their potential application.

Förster共振能量转移（FRET）探针是生物学中的独特工具，因为它们允许对生物分子或活细胞内人工底物的某种状态进行实时无损监测。FRET底物表明它们的相对裂解率，从而表明给定酶的原位活性。与淬灭探针或开启探针相反，FRET探针的两个单独信号之一可以用作内部参考，这使得比率成像和裂解事件定量与细胞递送无关。在这篇综述中，我们描述了与不同的替代探针相比的鞘脂FRET探针的第一个例子。最后，我们对未来的探针及其潜在应用进行了展望。