ABSTRACT
Objective:To development a new method for sensitive detection of Porphyromanus gingivalis (P.gingivalis) based on magnetic encoding nanospheres and upconversion fluorescent encoding nanospheres.Methods:Magnetic and upconversion fluorescent encoding nanospheres were prepared by sol-gel method respectively,combined the monoclonal antibodies specific to P.gingivalis after modifying the surface of nanospheres.The system was used to detect P.gingivalis from mixed bacteria solution of P.gingivalis,F.nucleatum and S.mutans.Fluorescent microscopy with an external 980 nm near-infrared hght pulse laser,scanning and transmission microscope were used to evaluate the effectiveness of the detection system.Results:Magnetic and upconversion encoding nanospheres had better dispersion,particle size uniformity and homogeneous morphology.Besides,the magnetic encoding nanospheres had good magnetic properties and strong fluorescence intensity.P.gingivalis was captured by magnetic and upconversion encoding nanospheres in a mixed solution of the 3 bacteria with a detection limit of 10 CFU/ml.Conclusion:The method designed in this study can capture P.gingivalis sensitively in a mixed bacteria liquid.