| Due to thespecialeffects of the metal nanoparticles, made them get unique physical, chemical and biological properties. So they were attractive in varieties of applications such as electron industry, pharmaceuticals industry, catalyst industry, biosensors and a series of fields. Their broad application prospect has aroused researchers’extensive attention, and one of the most fundamental and important work in the field of metal nanoresearch is the synthesis of nanoparticle. In this study, silver nanoparticles (AgNPs) were rapidly synthesized on eggshell membrane (ESM) to get a composite of silver nanoparticles/eggshell membrane (AgNPs/ESM). The synthesis method is with the advantage of mild condition, simple operation, and economic environment.The main research contents of the study as follows:1. The preparation and characterization of silver nanoparticles/eggshell membrane composite. AgNPs were synthesized on eggshell membrane by photochemical method. The color change after the reaction by means of visual observation; ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and energy-dispersive X-ray spectroscopy (EDX) confirmed the synthesis of AgNPs on the ESM; field emission scanning electron microscopy (FESEM) observed the microscopic surface structure of AgNPs/ESM; the morphology, dispersity and particle size distribution of AgNPs were characterized by high resolution transmission electron microscopy (HRTEM); X-ray diffraction (XRD) and selected area electron diffraction (SAED) characterized the crystalline structure of AgNPs.2. The antibacterial application of the AgNPs/ESM nano-biocomposite. The antibacterial activity against Escherichia coli DH5a and Staphylococcus aureus NICPBP 26003 was studied. The disk diffusion method was used for the antimicrobial activity testing.3. The application of AgNPs/ESM nano-biocomposite in immobilization of α-amylase. With the advantage of high specific surface area and mechanical strength, α-amylase was covalently immobilized on ESM and AgNPs/ESM with glutaraldehyde as the cross-linking agent, respectively. And the change of enzymatic properties between the free and immobilized α-amylase was studied.The results showed that:1. AgNPs can be synthesized by ESM reacting with silver nitrate under simulated sunlight. The same reaction system kept out of the light for the same reaction time did not show any color change of the ESM, suggesting that simulated sunlight played a crucial role in the synthesis of AgNPs.2. The Ag nanoparticles formed on ESM presented in spherical and were scattered without obvious agglomeration. Due to the different structure between the limiting membrane (LM) and outer shell membrane (OSM), the synthesized AgNPs were different in size distribution on the two surfaces of ESM. The results demonstrated that the sizes were almost in the range of 4.8-16.0 nm for the Ag nanoparticles on LM and 15.8-31.4 nm on OSM, and their mean diameters were 10.4 nm and 23.6 nm, respectively. The AgNPs on the two surfaces were face-centered cubic crystalline structure, and the spacings of lattice fringe were 0.231 nm and 0.245 nm for the Ag nanoparticles on LM and OSM, respectively.3. The nano-biocomposite AgNPs/ESM showed potential antibacterial activity, which was due to the AgNPs on ESM. The synthesized AgNPs/ESM exerted higher antibacterial activity against Gram negative bacterium E. coli than Gram positive bacterium S. aureu.4. Compared with the free amylase and amylase immobilized on ESM (amylase-ESM), the amylase immobilized on AgNPs/ESM (amylase-AgNPs/ESM) has wilder application conditions and better storage stability. |
