Orthogonal Upconversion Luminescent Nanoprobe For The Detection Of Nitric Oxide

Accurate and rapid medical diagnosis of biomarkers plays a key role in disease prevention,treatment and prognosis.Volatile organic compounds in exhaled gases have been thought to be closely related to the development process of many diseases,such as cancer,diabetes,etc.As a typical respiratory volatile organic compound,nitric oxide(NO)in exhaled air is considered a prognostic biomarker for some chronic respiratory diseases such as emphysema,bronchitis and asthma.Studies have shown that the activation of inducible nitric oxide synthase in respiratory epithelial cells leads to increased NO levels in respiratory gases.The relative concentrations of NO change in the pathological process of asthma,and there are also significant differences from individual age,sex and smoking habits in related physiological processes,ranging from sub ppb levels in healthy adults to hundreds of ppb levels in asthma adults.Therefore,accurate analysis of exhaled NO is a challenging task.At present,many sensing methods,such as gas chromatography-mass spectrometry and microchip based methods,have been applied to the monitoring of NO.However,these methods are time-consuming and require professional training,and most of them are not suitable for clinical rapid detection and other ultra sensitive analysis applications.Therefore,it is necessary to explore a portable detection strategy to improve the real-time perception performance of breath analysis.Aiming at the above challenges,this paper designs a new detection method with adjustable luminescence ratio,which greatly improves the detection effect of NO in exhalation.In this study,rhodamine spirolactam(Rd Ms),an organic dye molecule used as NO recognition unit,was encapsulated in a mesoporous silica layer on the surface of Upconversion nanoparticles(UCNPs).The principle is: in the detection process,Rd Ms can react with NO quickly to reduce the photosensitivity of Rd Ms.Under 808 nm excitation,the fluorescence resonance energy transfer occurs between the reduced organic dye molecules and UCNPs,which affects the green emission of the probe,but does not affect the red emission of ucnps under 980 nm excitation.Therefore,NO can be quantitatively detected by the degree of luminescent quenching,and the NO concentration in the sample can be accurately quantitatively detected according to the arbitrarily adjustable luminescent ratio of the probe.This advanced detection method is developed with a more portable smartphone detection system and has the characteristics of convenient use.The emission intensity ratio of orthogonal emission probe can be adjusted flexibly compared with ordinary proportional fluorescence probe,so that the detection limit of NO can be reduced to 0.5 ppb,and the linear detection range is increased from ppb to hundreds.Therefore,the comprehensive detection performance of this method is much higher than that of ordinary detection methods.