A hybrid nanocomposite combines two or more chemically distinct phases, at least one of which has a dimension below one hundred nanometres, so that the interface occupies a large fraction of the total volume ^[1]. The filler may be inorganic, organic or itself a hybrid, and the property that shifts most is the one governed by the boundary: thermal conductivity, gas sensitivity or stiffness ^[2]. Because the interfacial area per unit mass grows as the filler shrinks, a loading of a few per cent by volume already changes the response, and the percolation threshold falls as the aspect ratio rises ^[1]. Biological composites reproduce the same architecture at a larger scale, where mineral platelets in a protein matrix give stiffness without losing toughness ^[3]. Aggregation of the filler removes the interface the design depends on, so the dispersion state is reported alongside the loading ^[2].