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In order to design a painless and mechanically durable micro syringe-needle system for biomedical applications, the study of insect stingers is of interest because of their elegant structures and functionalities. In the present work, the structure, mechanical properties and the mechanical behavior during insertion of wasp and honeybee stingers have been investigated. The non-invasive imaging tool, micro-computed tomography has been employed to reveal the 3D-structures of wasp and honeybee stingers. A quasi-static nanoindentation instrument was used to measure the nanomechanical properties. Both wasp and honeybee stingers have graded mechanical properties, decreasing along their longitudinal direction starting from the base. The computed tomography images and the measured material properties from nanoindentation were fed into a computational framework to determine the mechanical behavior of the stingers during penetration. The computation results predicted the penetration angle of +10° for the wasp stinger and −6° for the honeybee stinger, which mimics the practical insertion mechanism of both stingers. Based on this understanding, a wasp and honeybee stringer inspired micro syringe-needle design has also been proposed. [ABSTRACT FROM AUTHOR]

A novel 8-hydroxy quinoline-derived amide receptor, in conjunction with its Cu (II) and Zn (II) complexes, has been strategically developed to function as remarkably efficient fluorescent receptors with a distinct capability for anion sensing. The comprehensive characterization of the synthesized compounds were achieved through UV-Vis, IR, NMR, and HRMS spectroscopic techniques. Among the Cu (II) and Zn (II) complexes, the latter exhibits superior selectivity for anions, specifically dihydrogen phosphate and hydrogen sulfate, as their tetrabutylammonium salts in a 9:1 acetonitrile-water (v/v) mixture. The Cu (II) complex demonstrates enhanced anion binding compared to the amide ligand, albeit with reduced selectivity. Furthermore, the affinity was evaluated using the Benesi-Hildebrand plot. The binding constants and Limit of Detection (LOD) for both complexes were precisely quantified. The Job plot illustrates a clear 1:1 binding interaction between the metal complexes and the guest anions. Significantly, both metal-complex receptors display a broad spectrum of antibacterial activity, against both gram-positive and gram-negative bacteria. It is worth highlighting that the Zn (II) complexed receptor outperforms the Cu (II) complexed receptor, as evidenced by its considerably lower Minimum Inhibitory Concentration (MIC) value against both bacterial strains. [ABSTRACT FROM AUTHOR]