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    Effects of diallyl trisulfide, an active substance from garlic essential oil, on structural chemistry of chitin in Sitotroga cerealella (Lepidoptera: Gelechiidae)
    (Academic Press Inc., 2022) Shah, Sakhawat; Ma, Min; Ali, Asad; Kaya, Murat; Li, Xue-Gang; Wu, Gang; Yang, Feng-Lian
    The environmental pollution, evolution of resistance, and risks to human and aquatic animal health associated with pesticide application have attracted much attention globally. Herein, we tested the capacity of diallyl trisulfide (DAT) from garlic essential oil to control the destructive stored-product pest, Sitotroga cerealella. The effects of DAT on the total content of cuticular chitin and structure of adults S. cerealella were evaluated. This study was the first to investigate changes in chitin structure in adults due to exposure to DAT through Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and differential scanning calorimetry. The results of these analyses revealed that the cuticular chitin content of pests decreased after DAT treatment. DAT treatment also reduced thermal stability and crystallinity of chitin. These findings indicate that DAT is a potent biopesticide that is active against the moth, and establishes the basis for its use as an IPM and alternative to chitin synthesis inhibitors.
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    From bio-waste to biomaterials: The eggshells of Chinese oak silkworm as templates for SERS-active surfaces
    (Elsevier B.V., 2021) Zang, Lian-Sheng; Chen, Yong-Ming; Koç Bilican, Behlül; Bilican, İsmail; Şakir, Menekşe; Wait, James; Çolak, Arzu; Karaduman, Tuğçe; Ceylan, Ahmet; Ali, Asad; Elbuken, Çağlar; Önses, M. Serdar; Kaya, Murat
    Although over 80% of the world's existing animal species are insects, with each of these species having unique eggshell morphologies, limited information is available regarding the use of their eggshells in material science applications. The present research discusses using discarded eggshells of the Chinese oak silkworm (Antheraea pernyi) as a technological material. The 3-dimensional aspects of the insect's eggshell were examined in detail, demonstrating the complexity of their novel surface morphology. The outer surface of the eggshell was comprised of a hexagonal structure, whereas the inner surface consists of a mostly smooth surface. Distinctive layers of the eggshell were observed when cross sections of the surface were analyzed. The elastic modulus of the inner part of the eggshell is substantially greater than that of the outer part. The physicochemical properties of the eggshell were characterized and no toxic properties were found. The hexagonal structures found on the outer surface of the eggshell provide a highly suitable template for silver nanostructure deposition. The resulting silver decorated surfaces can be used to detect molecules via surface-enhanced Raman scattering (SERS) effects. The deposition of silver renders the surface antimicrobial, whereas the original surface was microbial. Collectively, the insights gained in this study will be key in developing advanced engineering applications of the insect eggshells.
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    Production of natural chitin film from pupal shell of moth: Fabrication of plasmonic surfaces for SERS-based sensing applications
    (Elsevier Ltd, 2021) Chen, Yong-Ming; Pekdemir, Sami; Bilican, İsmail; Koç Bilican, Behlül; Çakmak, Betül; Ali, Asad; Zang, Lian-Sheng; Önses, M. Serdar; Kaya, Murat
    Commercially available types of chitin or chitin isolate are usually in powder form and are nanofibrous in microstructure. However, the surface characteristics of natural chitin in the body of insects are currently understudied. Herein, natural chitin film was successfully produced from bio-waste of insect pupae of the Japanese giant silkworm. Two different surface morphologies of the chitin film were observed. We report for the first time a micropapillary surface structure of chitin which was observed on the dorsal side of the film. To further potential of the micropapillary structured natural chitin in sensing applications, we develop a protocol for generating a nanoscopic film of Ag using thermal evaporation. The Ag-deposited natural chitin films exhibited surface-enhanced Raman scattering (SERS) activity to an extent depending on the structure of the film. In conclusion, materials science has been expanded by addition of a natural, three-dimensional chitin film with utilizable properties.