Preparation And Biochemical Analysis Research Of Nanocomposites Based On Upconversion Resonance Energy Transfer

Upconversion nanopaticles?UCNPs?are a new type of optical material that has been developed on the basis of quantum dots and organic dyes.Due to its inherent unique optical properties,it can convert near-infrared light with lower energy into higher energy ultraviolet light and visible light.Based on two-photon and multiphoton mechanisms,it has large anti-Stokes shift and photobleaching,narrow emission peaks and many other advantages.Therefore,these materials are widely used in many fields such as in vivo imaging,biosensing,drug release,photoactivation,and photodynamic therapy.In recent years,the use of upconverting nanoparticles as donors of energy and the use of other materials as energy acceptors has been well known in the development of fluorescence analysis by this mechanism of energy resonance transfer.The excellent comprehensive performance of nanocomposites is a hot material for scientists at home and abroad.Therefore,the development of a new type of nanocomposite sensor is of great significance for medical diagnostics,environmental science and food safety.This paper focus on the preparation and novel biochemical analysis of the upconversion resonance energy transfer nanocomposites.Combining the current development trend in this field,the upconversion nanomaterials are reacted with porphyrin hydrates to form nanocomposites,which undergo energy resonance transfer to change upconversion fluorescence and absorbance signal,and then realized the biochemical analysis of copper ions and phosphoric acid compounds through the change of upconversion fluorescence and absorbance signal regulated by target molecules.The full text is divided into three parts,as follows:Chapter 1.OverviewFirstly,this chapter introduces fluorescent nanomaterials and their research progress,and then focuses on the upconversion luminescent materials,including the optical properties of upconverting nanomaterials,the regulation strategy of upconversion nanomaterials,receptor research and research progress in converting nanomaterials.Finally,the significance and main content of this paper are expounded.Chapter 2.Lanthanide-doped nanoparticles encountering porphyrin hydrate:Boosting a dual-mode optical nanokit for Cu²⁺sensingThis chapter designs a facile dual-mode optical nanokit for Cu²⁺detection,which has been developed based on a distinctive synergy between ligand-free lanthanide-doped upconversion nanoparticles?UCNPs?and porphyrin hydrate.The UCNPs can readily combine a commercially available porphyrin hydrate?tetraphenylporphyrin tetrasulfonic acid hydrate,TPPS?to form UCNPs/TPPS complex,showing a green color from TPPS and low upconversion fluorescence of UCNPs quenched by TPPS due to fluorescence resonance energy transfer?FRET?.Then,a distinctive synergy between UCNPs and TPPS would be generated including the Cu²⁺-regulated color change of TPPS and its concomitant inhibiting effect on the preceding FRET.Because of such distinctive synergy,UCNPs/TPPS has been demonstrated to be a novel dual-mode colorimetric and fluorometric nanokit for Cu²⁺monitoring with high sensitivity and selectivity.This work unveils a smart strategy for dual-mode optical assay and would promise new opportunities for the development of multifunctional sensing platforms for various applications.Chapter 3.pH-Regulated Optical Performances in Organic/Inorganic Hybrid:A Dual-Mode Sensor Array for Pattern-Recognition-Based BiosensingThis chapter is based on TPPS can assemble onto the ligand-free Ln-UCNPs to construct the organic/inorganic hybrid?TPPS/Ln-UCNPs?,leading to a new absorption band to quench the upconversion fluorescence of Ln-UCNPs due to fluorescence resonance energy transfer?FRET?.We herein unveil a novel dual-mode optical?i.e.,UV-vis absorption and fluorescence?method for multifunctional sensing of phosphate compounds?PCs??e.g.,nucleotides and pyrophosphate?based on pattern recognition.The resulting TPPS/Ln-UCNPs can be adjusted by pH?e.g.,pH 4,4.5 and 5?to show different optical properties for UV-vis absorption and fluorescence,thus developing a dual-mode sensing array(i.e.,TPPS/Ln-UCNPs₄,TPPS/Ln-UCNPs_4.5 and TPPS/Ln-UCNPs₅),which would result in individual dual-mode optical response patterns upon being challenged with PCs for their pattern recognition through a competitive mechanism between TPPS and PCs.The results show that three TPPS/Ln-UCNPsn sensors can successfully permit the sensitive detection of 14 PCs and differentiate them between different concentrations,as well as a mixture of them.The pH dependent TPPS/Ln-UCNPs promises the simple,yet powerful discrimination of PCs via pattern recognition,would prospectively stimulate and expand the use of organic/inorganic hybrid toward more biosensing applications.