Biomimetic Metal–Organic Nanotubular Host for Straight-Chain Fatty Acids Recognition

Subtle structural variations among
fatty acids significantly influence
their biological roles and health effects. However, molecular recognition
of their long, flexible, and chemically inert hydrocarbon chains remains
a challenge. Inspired by natural fatty acid-binding proteins (FABPs),
we designed and synthesized nanotubular metallo-cavitands, termed
metal–organic pillars, through the coordination-driven assembly
of pillararene-derived ligands with Ag(I) salts. These biomimetic
hosts feature continuous interior channels exceeding 2.6 nm, selectively
binding long-chain fatty acids through precise size and shape complementarity.
Saturated and trans fatty acids, with linear conformations,
are effectively encapsulated and stabilized by C–H···π
and van der Waals interactions. In contrast, coiled cis-polyunsaturated fatty acids, such as docosahexaenoic acid (DHA),
cannot be accommodated due to structural incompatibility. This work
highlights the ability of artificial receptors to emulate the recognition
capabilities of natural proteins, enabling the targeting of “bad”
fatty acids associated with adverse health effects.