Visual Analysis Of Orthogonal Luminescent Upconversion Nanoparticles

The acquisition of biomedical characteristic information requires the development of some rapid,real-time and intuitive analysis methods.The optical probe constructed based on the luminescence effect of nanomaterials is widely used in the field of biomedical visual analysis due to its advantages of rich surface recognition units and easy adjustment of spectral properties.The application of traditional nano-optical materials in biomedical visual analysis is greatly limited due to the shortcomings of strong background fluorescence,great damage to biological samples and poor optical stability caused by high energy uv-visible excitation.Upconversion luminescent nanomaterials can greatly reduce the interference of background fluorescence signal due to the using of near-infrared light excitation,and its unique optical properties make up for the shortcomings of traditional optical materials well.However,in the upconversion luminescence visual analysis,the common upconversion luminescence nanoprobes are difficult to identify the characteristic information of the system before or after detection due to their fluorescence enhancement or fluorescence quenching principle.In addition,in the traditional visual analysis,the concentration of the analyte is judged by the maked eye,which causes the problem of low accuracy because people have different sensitivity to colors.In this paper,two kinds of visual analysis techniques are developed based on upconversion luminescent nanomaterials to realize rapid detection of trace substances in complex systems such as fingerprints.The NaYF₄:Yb/Er/Mn@NaYF₄:Yb@NaNdF₄upconversion nanoparticle doped by a single rare-earth activator with orthogonal luminescence characteristics was firstly designed and synthesized.The orthogonal luminescence performance was successfully optimized through the regulation of Mn²⁺doping concentration to 40%.Then,the principle of orthogonal luminescence of the nanoparticles with core-shell-shell structure was studied.The path of energy transfer varied with the distance between sensitizer Nd³⁺and activator Er³⁺,therefore the mechanism of orthogonal luminescence caused by the variation in energy migration was explored.Finally,the orthogonal luminescence upconversion nanoparticles were modified with polyethylenimine,and the accurate detection of TNT residue in fingerprint while imaging fingerprint was successfully realized by applying the principle of fluorescence resonance energy transfer.The successful preparation and application of the orthogonal luminescent upconversion nanoparticles will further enhance the synchronous detection capability of visual analysis technology.Aiming at the problem of poor accuracy of traditional visual analysis,the upconversion detection platform based on smartphone was further constructed through independent design.The NaYF₄@NaYF₄:Yb/Tm nanoparticles were used to detect SO₂in the air,and the results were comparable to those tested by the standard method of the environmental protection department.The construction of this smartphone platform will further improve the quantitative analysis ability of visual detection.In this paper,the orthogonal upconversion luminescence property of the same rare-earth activator ion was realized by reasonably designing the doping position of each rare-earth ion in the particles with core-shell-shell structure,and a new orthogonal visual analysis strategy was developed to realize the fingerprint imaging and the fast detection of trace objects in fingerprint simultaneously.Furthermore,by constructing a smartphone detection platform,the quantitative analysis with visual test paper was realized.The visual analysis method developed in this paper will provide a new research idea for the application of upconversion luminescent nanomaterials in biomedical detection.