The biological performance of artificial biomaterials is closely related to their structure characteristics. Cell adhesion, migration, proliferation, and differentiation are all strongly affected by the different scale structures of biomaterials. Silk fibroin (SF), extracted mainly from silkworms, has become a popular biomaterial due to its excellent biocompatibility, exceptional mechanical properties, tunable degradation, ease of processing, and sufficient supply. As a material with excellent processability, SF can be processed into various forms with different structures, including particulate, fiber, film, and three-dimensional (3D) porous scaffolds. This review discusses and summarizes the various constructions of SF-based materials, from single structures to multi-level structures, and their applications. In combination with single structures, new techniques for creating special multi-level structures of SF-based materials, such as micropatterning and 3D-printing, are also briefly addressed.

Multifunctional robust TiO₂@fabrics with special wettability demonstrated potential applications for excellent UV shielding, effective self-cleaning, efficient oil–water separation and microfluidic management.

Oil–water separation is critical for the water treatment of oily wastewater or oil-spill accidents. In this review, we present the state-of-the-art developments in the rational design of materials at the nanoscale with special wettability for separation of immiscible/emulsified oil–water mixtures.

An ultrasonication-assisted in situ deposition strategy was developed to realize uniform Ag nanoparticles dispersed on TiO ₂ nanotube arrays (Ag@TiO ₂ NTAs).

The development of scalable and reliable three-dimensional macroscopic functional aerogels is of remarkable significance because of their wide applications in the energy and environmental fields. Although the metal–organic frameworks (MOFs) have shown promising applications in water remediation, the construction of MOFs-based aerogels is highly challenging. Herein, for the first time, we report a general strategy for one-step fabrication of a ZIF-8 MOF/reduced graphene-oxide hydrogel in a short period via self-assembly, with the synergistic effects of chemical reduction and cross-linking by metal ions; upon drying, the hydrogel yields the ZIF-8/reduced graphene-oxide aerogel. The highly porous ZIF-8 hybrid aerogel displays high absorption capacity and cycling stability for oils and organic solvents, due to its superhydrophobic properties and high specific surface areas. In addition, the corresponding hydrogel demonstrates photocatalytic dye degradation ability, as well as excellent water purification performance for removing toxic dyes, heavy metal ions and benzo pollutants. Our synthetic strategy is proven to be versatile for constructing a variety of functional nanocomposite hydro-/aerogels towards customized water remediation.

Colorimetric sensing, which transduces environmental changes into visible color changes, provides a simple yet powerful detection mechanism that is well-suited to the development of low-cost and low-power sensors. A new approach in colorimetric sensing exploits the structural color of photonic crystals (PCs) to create environmentally-influenced color-changeable materials. PCs are composed of periodic dielectrics or metallo-dielectric nanostructures that affect the propagation of electromagnetic waves (EM) by defining the allowed and forbidden photonic bands. Simultaneously, an amazing variety of naturally occurring biological systems exhibit iridescent color due to the presence of PC structures throughout multi-dimensional space. In particular, some kinds of the structural colors in living organisms can be reversibly changed in reaction to external stimuli. Based on the lessons learned from natural photonic structures, some specific examples of PCs-based colorimetric sensors are presented in detail to demonstrate their unprecedented potential in practical applications, such as the detections of temperature, pH, ionic species, solvents, vapor, humidity, pressure and biomolecules. The combination of the nanofabrication technique, useful design methodologies inspired by biological systems and colorimetric sensing will lead to substantial developments in low-cost, miniaturized and widely deployable optical sensors.