Search Results (5)

The aim of our study was to determine the importance of different pitcher syndrome characters (size of the trap, the presence of inner microscopic surface coverage, physical properties of the pitcher fluid) for insect trapping efficiency using artificial, “biomimetic” pitchers. We performed trapping experiments with Drosophila melanogaster flies, applied cryo scanning electron microscopy for characterization of the topography of surface coatings and visualization of their contaminability effects on insect attachment organs, and conducted contact angle measurements with different liquids used in experiments. The type of the liquid used as the pitcher fluid had the most important impact on the trapping efficiency; surfactant-containing liquids exhibiting strong wetting properties provided a high number of trapped flies. The diameter of the trap rather than its height influenced insect trapping efficiency; apparently, because wider traps provide a larger space for more insects to get into a trap, they captured more flies in comparison to narrower traps. The presence of both the calcium carbonate and kaolin coatings mimicking the epicuticular wax coverage inside pitchers in many Nepenthes species additionally contributed to the trapping success due to a reduction of contact between insect feet and the trap surface and to contamination of flies’ attachment organs by detached microparticles. Full article

Collecting fog water is crucial for dry areas since natural moisture and fog are significant sources of freshwater. Sustainable and energy-efficient water collection systems can take a page out of the cactus’s playbook by mimicking its native fog gathering process. Inspired by the unique geometric structure of the cactus spine, we fabricated a bioinspired artificial fog collector consisting of cactus spines featuring barbs of different sizes and angles on the surfaces for water collection and a series of microcavities within microchannels inspired by Nepenthes Alata on the bottom to facilitate water flowing to the reservoir. However, replicating the actual shape of the cactus spine using conventional manufacturing techniques is challenging, and research in this area has faced a limitation in enhancing water-collecting efficiency. Here, we turned to 3D printing technology (vat photopolymerization) to create bio-mimetic fog collectors with a variety of geometric shapes that would allow for the most effective conveyance and gathering of water. Various barb sizes, angles between each barb in a single array, spine and barb arrangements, and quantity of barbs were tested experimentally and numeric analysis was carried out to measure the volume of water collected and optimize the mass rate. The result shows that optimal fog collection is with a mass flow rate of 0.7433 g/min, with L_i = 900 μm, θ = 45°, ϕ = 90°, N_b = 2, and N_s = 5. This study presents a sustainable and ecologically sound method for efficiently collecting humid air, which is expected to be advantageous for the advancement of future-oriented fog-collection, water-transportation, and separation technologies. Full article

The carnivorous pitcher plant, Nepenthes × ventrata (Hort. ex Fleming = N. ventricosa Blanco × N. alata Blanco), produces passive traps containing digestive fluid. Although reactive oxygen species (ROS) in the fluid were detected in some pitcher plants, the participation of reactive nitrogen species (RNS) in the digestion process has not yet been examined. The aim of this work was to investigate the production of superoxide anion (O₂^•−), nitric oxide (NO) and peroxynitrite (ONOO⁻) levels in the digestive fluid of traps throughout organ development. We revealed the ROS and RNS occurrence in the digestive fluid, linked to the ROS-scavenging capacity and total phenolics content. In digestive fluid from the fed traps, NO emission was higher than in the fluid from the developed unfed pitcher. The concentration of nitrite (NO₂⁻) decreased in the fluid from the fed traps in comparison to the unfed ones, pointing at NO₂⁻ as the key source of NO. The enhanced emission of NO was associated with lowered content of ONOO⁻ in the fluid, probably due to lower production of O₂^•−. At the same time, despite a decline in total phenolics, the maximum ROS scavenging capacity was detected. In addition, ROS and RNS were noted even in closed traps, suggesting their involvement not only in digestion per se but also their action as signaling agents in trap ontogeny. Full article

Unidirectional liquid spreading without energy input is of significant interest for the broad applications in diverse fields such as water harvesting, drop transfer, oil–water separation and microfluidic devices. However, the controllability of liquid motion and the simplification of manufacturing process remain challenges. Inspired by the peristome of Nepenthes alata, a surface-tension-confined (STC) channel with biomimetic microcavities was fabricated facilely through UV exposure photolithography and partial plasma treatment. Perfect asymmetric liquid spreading was achieved by combination of microcavities and hydrophobic boundary, and the stability of pinning effect was demonstrated. The influences of structural features of microcavities on both liquid spreading and liquid pinning were investigated and the underlying mechanism was revealed. We also demonstrated the spontaneous unidirectional transport of liquid in 3D space and on tilting slope. In addition, through changing pits arrangement and wettability pattern, complex liquid motion paths and microreactors were realized. This work will open a new way for liquid manipulation and lab-on-chip applications. Full article

Heat control has been a momentous problem in engineering areas which include manufacturing, aeronautics, microchips and so forth for a considerable amount of time. The control of material for thermal deformation, effective cooling are the key components of the aero crafts and compactly laid out microchips are urgently needed for improvement. In a micro-scale, researchers are mainly focused on the mechanism, design, improvement and heat transfer of straight channels other than developing other types of channels. A previous study on the carnivorous plant, Nepenthes alata, indicates that the water can be transported continuously and directionally on the surface of the rim of the pitcher because of its multi-scale structures. Meanwhile, the transporting speed is much higher than what was thought previously. Inspired by this unique phenomenon, the heat management ability of this biological micro channel is investigated in this research. Firstly, based on existing studies, the features of the biological channels are extracted. Then, the unidirectional channels are designed and fabricated by elliptical vibration cutting accordingly. The experimental platform for thermal control was established consequently. Both bio-inspired and straight triangular channels of the same depth and width were set for comparison. Through the comparative experiments, it is concluded preliminarily that the critical point of heat transfer performance of the two channels exists, and the biomimetic structure can improve and strengthen the cooling effects at a large flow rate because of the unique geometric structure. The temperature reduction of the bio-inspired channels can be increased by up to 84 percent compared with straight channels in a single experiment when heated up to 150 centigrade. Full article