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Researchers led by Professor Yi-Tsu Chan at National Taiwan University have created a giant molecular cage that mimics nature's nested structures. This layered nanocage is remarkably stable and can serve as a miniature reactor for producing gold nanoparticles.

Nested structures—where one architecture is enclosed within another—are common in nature, from the protective shells of viruses to the compartmentalized organization of living cells. These sophisticated designs allow biological systems to perform multiple functions within confined spaces. Yet, reproducing such complexity at the molecular level in the laboratory has remained a formidable challenge.

A research team at National Taiwan University, led by Professor Yi-Tsu Chan, has now taken a major step forward by designing a new type of molecular building block that self-assembles into a highly stable, layered cage.

The resulting nanocage features two distinct layers: an inner octahedron encapsulated within an outer truncated tetrahedron. Together, they form a giant supramolecular structure weighing more than 44,000 daltons.

The study is in the Journal of the American Chemical Society.

The breakthrough was made possible by creating a complementary pair of chemical "ligands," or connectors, that attach to metal ions in a way that is both dynamic and highly selective. This design prevents unwanted side reactions and locks the structure into place, giving the nanocage exceptional stability over extended periods.

To confirm the intricate structure, the researchers combined state-of-the-art imaging and analytical methods, including high-field nuclear magnetic resonance (NMR), small-angle X-ray scattering (SAXS), cryo-electron microscopy (cryo-EM), and high-resolution electron microscopy. These techniques provided a detailed view of the architecture down to the single-molecule level.

Beyond its striking structural design, the nanocage also demonstrates functional potential. Its hollow interior can act as a nanoscale reaction chamber. In one test, the team successfully generated gold nanoparticles inside the cavity, showcasing its promise as a tiny chemical reactor.

"This work shows how carefully designed molecular interactions can lead to precise and durable architectures that echo nature's complexity. We believe our approach opens new opportunities in advanced materials, nanotechnology, and catalysis," says Prof. Yi-Tsu Chan, corresponding author of the study.