In situ surface-enhanced Raman scattering detection of biomolecules in the deep ocean

In this study, we successfully developed a new type of surface-enhanced Raman scattering insertion probe (RiP-SERS) applicable to the deep sea using previously prepared Coccinella septempunctata-shaped SERS substrate, and successfully obtained the Raman spectrum of biomolecules in deep-sea cold seep vents. The experiment proved that the SERS substrate was not remarkably affected by the change in depth (pressure) in the deep sea; therefore, it had excellent pressure resistance. More importantly, Raman peaks of various biomolecules, including acetyl-CoA, β-carotene, and four amino acids, were successfully collected from the microbial communities at the seawater-sediment interface of cold seep vents. The successful application of SERS technology to deep-sea in situ biomolecule detection has added a new method for deep-sea biomolecule detection in the future. Meanwhile, the SERS substrate can withstand a complex deep-sea cold-seep environment (pressure, salinity, pH, and metal-salt presence), which also means that it can be applied to the detection of macromolecules in complex industrial systems.