Janus Protein Nanoparticles Tailoring Bicontinuous Aerogels for Efficient Heavy Metal Ion Absorption

Bicontinuous structures are exquisite interpenetrating constructs with an optimal balance between connectivity and surface area. Such unique geometry favors exceptional mechanical properties and efficient inward mass diffusion essential for an absorbent material. Although bicontinuous structures are found across many length scales in nature, synthesizing artificial analogs using biological building blocks remains largely unexplored. In this study, it is shown that manipulation of the surface chemistry of rapeseed cruciferin nanoparticles (≈50 nm) leads to the formation of a highly amphiphilic stabilizer, ensuring equal wetting of water and oil phases in a demixed system, thereby enabling the formation of bicontinuous emulsions. By further eliminating both volatile liquid phases (water and toluene) through freeze-drying, bicontinuous emulsions are transformed into bicontinuous aerogels featuring highly interpenetrating networks with uniform domain size. These materials, characterized by high surface area (224 m² g^-1) and mechanical robustness, can efficiently absorb various heavy metal ions multiple times displaying excellent absorption capacity (up to 200 mg g^-1) and efficiency (less than 30 min). This study is at the forefront of constructing biomacromolecular bicontinuous structures, potentially expanding their applications in diverse fields such as food, cosmetics, and medicine.