As these microsized tubes spin through this solution, they help researchers do Raman spectroscopy. The tubes were made in the lab of Teng Qiu of Southeast University in China using three layers: nanotextured gold on the outside, silicon oxide in the middle, and iron on the inner wall. The gold outer shell does the heavy-lifting spectroscopy-wise: it can bind molecules in solution, and because of the textured surface, it can boost the Raman signal the molecules produce in what’s called surface-enhanced Raman spectroscopy, or SERS. This surface effect can make it 100,000 times easier to sense compounds. The silicon oxide layer helps the tubes initially roll up from flat multilayer disks, and lastly, the iron layer makes the tubes ferromagnetic and lets researchers steer them around using a rotating magnetic field.
Credit: Xingce Fan and Teng Qiu. Read the paper here in ACS Applied Materials & Interfaces (2020, DOI: 10.1021/acsami.0c05371).
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