Preparation And Application Of Biosensors Based On Fluorescent Nanoparticles

Upconversion nanoparticles(UCNPs)have the high penetration of near-infrared laser,no cell and tissue damage,high signal to noise and good compatibility.Therefore,UCNPs have great value in these fields of biological fluorescent imaging,bio-detection and drug therapy,which is also a popular topic in the world.In this paper,we mainly study the biosensors based on banoparticles,which has been successfully prepared,plants imaging in vivo,accurate detection of rhodamine B(RB)and glycated hemoglobin(Hb A1c)in blood,and these results are included as following:(1)Multicolor upconversion luminescence was tuned successfully.Uniform upconversion nanoparticles with uniform size and intense visible fluorescence were successfully synthesized by the solvothermal method,and which was the key materials for the preparation of thin film luminescence sensor.The UCNPs can emit visible color under the excitation of 980 nm laser.(2)The biosensor used for cell imaging.Compared with the conventional optical imaging,the upconversion fluorescent imaging can be conducted directly without slicing process and trauma,which provide navigation for the disease diagnose and therapy.It is expected to be used for accurate positioning of human tissue lesions,to provide the necessary basis for further treatment of lesions,based on the principle of differential imaging.(3)Detection of organic dyes based on nanoparticle biosensor.Based on the basic principle of Fluorescence resonance energy transfer(LRET),the sensing system is constructed.The integrated intensity ratio of the green emission of upconversion nanoprobes and red emission of Rhodamine.The concentration of RB can be easily addressed according to integrated intensity ratio of the red to green(IIRRG)signal.(4)Detection and analysis of Hb A1 c using array biosensor.Upconversion nanoparticle arrays biosensor were designed and fabricated,which can be used for detecting Hb A1 c through the LRET from UCNPs to HbA1 c.The extinction effect of the UCNPs arrays contributed to the enhancement of the detection sensitivity.In comparison to the direct detection in solution,this method presents higher sensitivity to the concentration variation(~4 times of that in solution),better reproducibility of the fluorescent signals(Deviation: 0.4~1.8% on array),and good reusability(repeated 20 times without obvious deviation).