Department of Periodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai 600077, Tamil Nadu, India.
Department of Periodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai 600077, Tamil Nadu, India.
Microb Pathog. 2024 Aug;193:106725. doi: 10.1016/j.micpath.2024.106725. Epub 2024 Jun 6.
Fish-borne pathogens such as A. hydrophila and F. aquidurense are the most resistant strains in pisciculture farming. Removing the aforementioned pathogens without antibiotics presents a formidable challenge. To overcome this problem, silver nanoparticles (AgNPs) are synthesized using silver nitrate, water medium, and as an AzadirachtaIndica leaf extract via the green synthesis route. X-ray diffraction (XRD) pattern results authenticate the synthesized material is the face-centered cubic structure of silver. The optical absorption edge of the synthesized product was found at the wavelength of 440 nm from the UV-visible spectra, which is confirmed to relate to the Surface Plasmon Resonance peaks of silver particles. In addition, the optical band gap value of the synthesized Ag sample is measured to be 2.81 eV from the obtained optical absorption spectra. EDX spectrum of the synthesized product also supports confirming the silver particle formation. The FT-IR spectra of the neem extract and silver nanoparticles showed their characteristic functional groups, respectively. The presence of bands between 1000 cm to 500 cm indicates to the formation of silver particles. Spherical particles appeared in the synthesized Ag using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The particle size of Ag NPs was measured as 40 nm and 62 ± 10 nm by TEM and Dynamic Light Scattering (DLS). The zeta potential was also measured as -12 mV showing the synthesized sample's stable nature. Using the DPPH assay, synthesized AgNPs were taken along with the various concentrations of ascorbic acid (20, 40, 60, 80, and 100 μg/mL) to examine the free radical scavenging activity (RSA). RSA value is higher (84 ± 2 %) for synthesized AgNPs at higher concentration (100 μg/mL) than 21 ± 2 % at low concentration (100 μg/mL). The antimicrobial efficacy of the AgNPs against A. hydrophila and F. aquidurense was performed through the agar diffusion method and its results showed the inhibitory zones of the F.aquidurense and A. hydrophila were measured as 25 ± 3 mm, and 28 ± 4 mm respectively. The synthesized Ag particles showed excellent antimicrobial and antioxidant properties confirmed by antimicrobial and DPPH experiments. It implies that the green synthesized silver nanoparticles could be a good alternative for antibiotics in aquaculture farms. The exposure of low concentrations of silver nanoparticles to zebrafish and brine shrimp does not affect the viability and morphology. The exposure of silver nanoparticles in the fisheries in optimized concentration and time could control the fish-borne pathogens without antibiotics.
鱼类病原体，如嗜水气单胞菌和豚鼠气单胞菌，是水产养殖中最具耐药性的菌株。在没有抗生素的情况下去除上述病原体是一项艰巨的挑战。为了克服这个问题，使用硝酸银、水介质和印楝叶提取物通过绿色合成路线合成了银纳米粒子（AgNPs）。X 射线衍射（XRD）图谱结果证实合成材料为银的面心立方结构。从紫外-可见光谱中发现合成产物的光吸收边缘在 440nm 处，这与银颗粒的表面等离子体共振峰有关。此外，从获得的光吸收光谱中测量合成 Ag 样品的光学带隙值为 2.81eV。合成产物的 EDX 光谱也支持确认银颗粒的形成。合成产物的傅里叶变换红外光谱（FT-IR）分别显示了它们的特征官能团。在 1000cm 到 500cm 之间的波段的存在表明形成了银颗粒。扫描电子显微镜（SEM）和透射电子显微镜（TEM）显示合成 Ag 中出现了球形颗粒。使用 TEM 和动态光散射（DLS）测量 AgNPs 的粒径为 40nm 和 62±10nm。通过 DPPH 测定法，还测量了银纳米粒子的zeta 电位为-12mV，表明合成样品具有稳定的性质。使用 DPPH 测定法，将合成的 AgNPs 与不同浓度的抗坏血酸（20、40、60、80 和 100μg/mL）一起进行，以检查自由基清除活性（RSA）。在较高浓度（100μg/mL）下，合成 AgNPs 的 RSA 值（84±2%）高于低浓度（100μg/mL）下的 21±2%。通过琼脂扩散法对 AgNPs 对嗜水气单胞菌和豚鼠气单胞菌的抗菌功效进行了测试，结果表明，F.aquidurense 和 A. hydrophila 的抑菌圈分别为 25±3mm 和 28±4mm。合成的 Ag 颗粒表现出优异的抗菌和抗氧化性能，这一点通过抗菌和 DPPH 实验得到了证实。这意味着绿色合成的银纳米粒子可以成为水产养殖中抗生素的替代品。将低浓度的银纳米粒子暴露于斑马鱼和丰年虾中不会影响其生存能力和形态。在优化的浓度和时间内将银纳米粒子暴露在渔业中可以控制鱼类病原体而无需使用抗生素。
