MicroRNAs (miRNAs), a kind of single-stranded small RNA molecules, play a crucial role in physiological and pathological processes in human beings. We describe here the detection of miRNA, by side-by-side self-assembly of plasmonic nanorod dimers in living cells, which gives rise to a distinct intense chiroplasmonic response and surface-enhanced Raman scattering (SERS). The dynamic assembly of chiral nanorods was confirmed by fluorescence resonance energy transfer (FRET), also in living cells. Our study provides insights into in situ self-assembly of plasmonic probes for the real-time measurement of biomarkers in living cells. This could improve the current understanding of cellular RNA-protein complexes, pharmaco-genomics, and genetic diagnosis and therapies.

Chiral inorganic nanomaterials have recently attracted significant attention because of their many important applications, such as in asymmetric catalysis and chiral sensing. Here, chiral iron disulfide quantum dots (FeS2 QDs) are synthesized via chirality transfer using l/d‐cysteine (Cys) as chiral ligands. The chiral FeS2 QDs are coassembled with two gelators to produce a cogel (l‐ or d‐[Gel+FeS2]) with a g‐factor value of ±0.06. Interestingly, the cogels display intense circularly polarized luminescence. More significantly, the degree of twisting (twist pitch) and the diameter of the cogels can be markedly regulated by illumination with circularly polarized light (CPL) in the ranges of 120–213 and 37–65 nm, respectively, which is caused by the CPL‐induced electron transfer. This research opens the way for the design of chiroptical devices with a wide range of functions and applications.

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