Enabling water-based high-density nanoparticles assembly by using silk fibroin as an adsorbate.

Water-based fabrication holds promise for innovations in life sciences, electronics, and materials science at the biotic-abiotic interface by integrating living systems with high technologies. However, using water to create bio-nano interfaces is challenging, as it often requires surface pre-treatment and thermal processing, which are both harmful to living systems. Here, we propose silk fibroin (SF) as a natural adsorbate that enables the fabrication of high-density nanoparticle (NP) layers relying solely on water-based processing. We show that SF spontaneously adsorbs onto various NPs, enhancing intermolecular interactions and facilitating the wetting of otherwise hydrophobic substrates, resulting in densely packed NP layers. Several SF-adsorbed NP electronics are demonstrated with performance comparable to their conventional counterparts. This work offers significant utility by establishing a flexible and biocompatible approach for the fabrication of seamless, precisely controlled bio-nano interfaces.