Fluorescently Labeled Gelatin Nanoparticle Surface Functionalized Fiber Membrane For Rapid And Highly Sensitive Detection Of Bacteria

Bacterial contamination is one of the most common contaminations in the food field.Most of the diseases in all diseases around the world are caused by some pathogenic bacteria.Therefore,it is of great significance to develop a simple,rapid,specific and highly sensitive bacterial detection method for improving human public health and safety index.Gelatin nanoparticles are widely used in the research of bacterial detection materials because of their large specific surface area and good drug loading performance.In this study,the prepared fluorescently labeled gelatin nanoparticles(GNP@FITC)were adsorbed on the nanofiber membrane by a simple vacuum filtration method to achieve specific detection of bacteria.The specific research contents of this topic are as follows :(1)GNP@FITC was prepared by a two-step desolvation method,and the effects of preparation conditions(different p H values)on particle size were investigated.At the same time,the particle size,Zeta potential and microstructure were characterized and analyzed.The results showed that GNP@FITC with particle size between 400 nm and 600 nm was successfully prepared by adjusting the p H value.The particle size was uniform and the dispersion performance was good(monodispersity coefficient,PDI < 0.1).(2)The nanofiber membrane with high specific surface area was selected as the substrate,and GNP@FITC was adsorbed on the surface of the membrane to obtain the surface functionalized nanofiber membrane.The microstructure and anti-interference of the surface functionalized fiber membrane with different GNP@FITC contents were investigated.The results showed that the particles on the surface of the functionalized modified fiber membrane were uniform in size,smooth without bulge and not easy to fall off,and also had good stability.(3)By monitoring the changes of particle size and structure of gelatinase after the response experiment of gelatinase to GNP@FITC,the bacterial detection mechanism of gelatin nanoparticles was explored,and the relationship curve between different gelatinase concentration and fluorescence change intensity was established.Pseudomonas aeruginosa and Staphylococcus aureus were used as model bacteria to secrete gelatinase.The stimulation response of GNP@FITC and surface functionalized fibrous membranes to different bacteria was investigated.The relationship between bacterial concentration and fluorescence intensity of nanoparticles or surface functionalized fibrous membranes was established.The anti-interference performance of different metal ion solutions was also systematically explored.The surface functionalized fiber membrane was used to determine different concentrations of bacteria in milk,tap water and juice,and to explore the detection performance in the actual environment.The results showed that different concentrations of gelatinase were positively correlated with the amount of fluorescent substance released by GNP@FITC,indicating that GNP@FITC had a strong response to gelatinase.At the same time,the specific detection of bacteria by GNP@FITC and surface functionalized fiber membrane was realized.The shortest detection time for high concentration samples was 2.3 h,and the detection limit was 0.1 CFU / m L.