The first black phosphorus (BP)-fiber-optic biosensor was proposed by Zhou et al. for the ultrasensitive detection of human neuron-specific enolase (NSE) cancer biomarkers [137], which has been shown in Figure 11A. This new optical nano-configuration, in which BP is biofunctionalized by poly-l-lysine as a key crosslinker, has been exploited to promote the bio-nano-photonic interface with extremely strong light-matter interaction. This evidence concerns the gene ENO2 and cancer.