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TiO 2 nanohelices (NHs) have attracted extensive attention owing to their high aspect ratio, excellent flexibility, elasticity, and optical properties, which endow promising performances in a vast range of vital fields, such as optics, electronics, and micro/nanodevices. However, preparing rigid TiO 2 nanowires (TiO 2 NWs) into spatially anisotropic helical structures remains a challenge. Here, a pressure-induced hydrothermal strategy was designed to assemble individual TiO 2 NWs into a DNA-like helical structure, in which a Teflon block was placed in an autoclave liner to regulate system pressure and simulate a cell-rich environment. The synthesized TiO 2 NHs of 50 nm in diameter and 5−7 mm in length approximately were intertwined into nanohelix bundles (TiO 2 NHBs) with a diameter of 20 μm and then assembled into vertical TiO 2 nanohelix arrays (NHAs). Theoretical calculations further confirmed that straight TiO 2 NWs prefer to convert into helical conformations with minimal entropy (S) and free energy (F) for continuous growth in a confined space. The excellent elastic properties exhibit great potential for applications in flexible devices or buffer materials.

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