Insect Analogue to the Lotus Leaf: A Planthopper Wing Membrane Incorporating a Low-Adhesion, Nonwetting, Superhydrophobic, Bactericidal, and Biocompatible Surface.

Nature has produced many intriguing and spectacular surfaces at the micro- and nanoscales. These small surface decorations act for a singular or, in most cases, a range of functions. The minute landscape found on the lotus leaf is one such example, displaying antiwetting behavior and low adhesion with foreign particulate matter. Indeed the lotus leaf has often been considered the "benchmark" for such properties. One could expect that there are animal counterparts of this self-drying and self-cleaning surface system. In this study, we show that the planthopper insect wing (Desudaba danae) exhibits a remarkable architectural similarity to the lotus leaf surface. Not only does the wing demonstrate a topographical likeness, but some surface properties are also expressed, such as nonwetting behavior and low adhering forces with contaminants. In addition, the insect-wing cuticle exhibits an antibacterial property in which Gram-negative bacteria (Porphyromonas gingivalis) are killed over many consecutive waves of attacks over 7 days. In contrast, eukaryote cell associations, upon contact with the insect membrane, lead to a formation of integrated cell sheets (e.g., among human stem cells (SHED-MSC) and human dermal fibroblasts (HDF)). The multifunctional features of the insect membrane provide a potential natural template for man-made applications in which specific control of liquid, solid, and biological contacts is desired and required. Moreover, the planthopper wing cuticle provides a "new" natural surface with which numerous interfacial properties can be explored for a range of comparative studies with both natural and man-made materials.

Xylitol enhances bacterial killing in the rabbit maxillary sinus.

OBJECTIVES: Factors that alter airway surface liquid (ASL) ionic concentrations may influence the course of sinusitis. Xylitol has been shown to effect ASL ionic composition in vitro and to reduce nasal bacterial carriage, otitis media, and dental caries in vivo. We examined the effect of xylitol on experimental sinusitis in the rabbit model. STUDY DESIGN: Prospective randomized controlled study of xylitol, saline, and Pseudomonas aeruginosa administration to the rabbit maxillary sinus. METHODS: P. aeruginosa was administered to the sinuses of 26 New Zealand white rabbits. Saline was placed in the left maxillary sinus and xylitol in the right. The rabbits were randomly assigned to one of three groups: one, simultaneous administration of bacteria and solutions with bacterial analysis at 20 minutes, 11 rabbits; two, preadministration of solutions 1 hour before bacterial infection with analysis at 20 minutes, 11 rabbits; three, established sinusitis, 4 rabbits had daily injections of solutions for 5 days starting 7 days after P. aeruginosa administration. RESULTS: In group 1, 6.96% of injected bacteria were retrieved on the left (saline), whereas 0.095% were retrieved on the right (xylitol) (P = .034). In group 2, 5.64% of inoculum was recovered from the left and 2.89% from the right (P = .188). Group 3 demonstrated evidence of sinusitis with recovery of noninoculate bacteria. with no difference between right and left. CONCLUSIONS: Xylitol reduces experimental sinusitis when administered simultaneously with bacteria. Its effect in established sinusitis is less clear. A role may exist for xylitol in nasal irrigation fluid in human disease.