Solar steam generation is regarded as a perspective technology, due to its potentials in solar light absorption and photothermal conversion for seawater desalination and water purification. Although lots of steam generation systems have been reported to possess high conversion efficiencies recently, researches of simple, cost-effective, and sustainable materials still need to be done. Here, inspired by natural young sunflower heads’ property increasing the temperature of dish-shaped flowers by tracking the sun, we used 3D-structured carbonized sunflower heads as an effective solar steam generator. The evaporation rate and efficiency of these materials under 1 sun (1 kW m–2) are 1.51 kg m–2 h–1 and 100.4%, respectively, beyond the theoretical limit of 2D materials. This high solar efficiency surpasses all other biomass-based materials ever reported. It is demonstrated that such a high capability is mainly attributed to the 3D-structured top surface, which could reabsorb the lost energy of diffuse reflection and thermal radiation, as well as provide enlarged water/air interface for steam escape. 3D-structured carbonized sunflower heads provide a new method for the future design and fabrication of high-performance photothermal devices.

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Surface plasmon resonance (SPR), a promising technology, is beneficial for various applications, such as photothermal conversion, solar cells, photocatalysts, and sensing. However, the SPR performance may be restricted by the 1D-or 2D-distributed hotspots. The bicontinuous interconnected gyroidstructured materials have emerged in light energy conversion due to a high density of 3D-distributed hotspots, ultrahigh light− matter interactions and large scattering cross-section. Here, a series of bioinspired Au−CuS gyroid-structured materials are fabricated by precisely controlling the deposition time of CuS nanoparticles (NPs) and then adopted for solar steam generation. Specifically, Au−CuS/GMs-80 present the highest evaporation efficiency of 88.8% under normal 1 sun, with a suitable filling rate (57%) and a large inner surface area (∼2.72 × 10 5 nm 2 per unit cell), which simultaneously achieves a dynamic balance between water absorption and evaporation as well as efficient heat conduction with water in nanochannels. Compared with other state-of-the-art devices, Au−CuS/GMs-80 steam generator requires a much lower photothermal component loading (<1 mg cm −2 ) and still guarantees outstanding evaporation performance. This superior evaporation performance is attributed to broadband light absorption, continuous water supply, excellent heat generation and thermal insulation, and good light−heat−water interaction. The combination of 3D interconnected nanostructures with controllable metal− semiconductor deposition could provide a new method for the future design of high-performance plasmonic devices.

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We performed a study of the nonlinear optical properties of chemically purified chitin and insect cuticle using two-photon excited autofluorescence (TPEF) and second-harmonic generation (SHG) microscopy. Excitation spectrum, fluorescence time, polarization sensitivity, and bleaching speed were measured. We have found that the maximum autofluorescence signal requires an excitation wavelength below 850 nm. At longer wavelengths, we were able to penetrate more than 150-um deep into the sample through the chitinous structures. The excitation power was kept below 10 mW (at the sample) in order to diminish bleaching. The SHG from the purified chitin was confirmed by spectral- and time-resolved measurements. Two cave-dwelling, depigmented, insect species were analyzed and three-dimensional images of the cuticular structures were obtained.

The present study describes utilization of two photon excitation fluorescence (2PE) microscopy for visualization of the hemoglobin in human and porcine erythrocytes and their empty membranes (i.e., ghosts). High-quality, label- and fixation-free visualization of hemoglobin was achieved at excitation wavelength 730 nm by detecting visible autofluorescence. Localization in the suspension and spatial distribution (i.e., mapping) of residual hemoglobin in erythrocyte ghosts has been resolved by 2PE. Prior to the 2PE mapping, the presence of residual hemoglobin in the bulk suspension of erythrocyte ghosts was confirmed by cyanmethemoglobin assay. 2PE analysis revealed that the distribution of hemoglobin in intact erythrocytes follows the cells’ shape. Two types of erythrocytes, human and porcine, characterized with discocyte and echinocyte morphology, respectively, showed significant differences in hemoglobin distribution. The 2PE images have revealed that despite an extensive washing out procedure after gradual hypotonic hemolysis, a certain amount of hemoglobin localized on the intracellular side always remains bound to the membrane and cannot be eliminated. The obtained results open the possibility to use 2PE microscopy to examine hemoglobin distribution in erythrocytes and estimate the purity level of erythrocyte ghosts in biotechnological processes.

The physical structure of teeth can be altered by diet, age or diseases such as caries or sclerosis. It is of utmost importance to characterize the mechanical properties to predict and understand tooth decay, to design restorative dental procedure, and to investigate the tribological behavior of teeth. Yet, existing imaging techniques are unable to reveal the micromechanics of the tooth, in particular at tissue interfaces. Here we developed a microscope based on Brillouin light scattering (BLS) to probe mechanical changes in tooth tissues. BLS is an inelastic process that uses the scattering of light by acoustic waves in the GHz range. Our microscope thus reveals the mechanical properties at a submicrometer scale without contact to the sample. BLS signals show significant differences between healthy tissues and pathological lesions, and allow delineating precisely destructed dentin. We also show maps of the sagittal and transversal planes of healthy tubular dentin that reveal its anisotropic microstructure with a 1 µm resolution, several orders of magnitude below previous reports. Our observations indicate that the collagen-based matrix of dentine is the main load bearing structure, which can be thought of as a fiber-reinforced composite. In the vicinity of polymeric tooth-filling materials, we observed fingering of the adhesive complex into the opened tubules of healthy dentine. The ability to probe the quality of this interfacial layer could lead to innovative designs of biomaterials used for dental restorations in contemporary adhesive dentistry, and would have direct repercussions on the decision-making during clinical work.

The iridescent features of the butterfly species Apatura iris (Linnaeus, 1758) and A. ilia (Denis & Schiffermüller, 1775) were studied. We recognized the structural color of scales only on the dorsal side of both the fore and hind wings of males of both of the aforementioned butterfly species. The scale dimensions and microstructure were analyzed by a scanning electron microscope (SEM) and transmission electron microscope (TEM). The optical properties were measured and it was found that the peak reflectivity is around 380 nm, with a spectral width (full width at half maximum) of approximately 50 nm in both species. The angular selectivity is high and a purple iridescent color is observed within the angular range of only 18 degrees in both species.