Single-component Sensor Array Based On Upconversion Nanomaterials And Its Application

With the improvement of productivity and living standards,it's urgently needed to develop the healthcare system,food and drug safety and environmental protection.Therefore,the requirements for analysis and detection performance are getting higher and higher.As a kind of fluorescence nanomaterial with excellent performance,upconversion nanoparticles(UCNPs)have huge application potential in biosensing.The development of fluorescence biosensors based on UCNPs has always been a hot research direction that researchers pay close attention to.In addition,the array type sensor has been widely used in many fields because it can identify multiple substances in high-throughput analysis.However,the commonly used fluorescence sensor array usually requires many steps of synthesizing multiple different sensing elements,and the preparation process is complicated and costly.Piking UCNPs as sensor element of the array sensor is one of the promising prospects of the fluorescence sensor array.It is of great significance to design a brilliant fluorescence sensor array to reduce the amount of materials required for sensing elements and reduce the cost of experiments and the difficulty of synthesis.Above all,we mainly aimed at the design of sensor arrays with upconversion nanomaterials.Focused on the important proposition of "single-component sensor array based on upconversion nanomaterials and its application",we strive to solve the problem of excessive materials required for the composition of the sensor array.For the first time,a new sensing strategy that using the multiple emission peaks of polydopamine-coated UCNPs as sensor array elements is proposed,which realized the identification of antioxidants.In addition,using the fluorescence response of polyacrylic acid functionalized core shell UCNPs to Cu²⁺,and adjusting the fluorescence response of the sensor by pH,a sensor array based on different buffer systems of the same material is designed,which can be used for biological thiols pattern recognition analysis.This paper is mainly divided into three parts,the specific content is as follows:Chapter 1 IntroductionFirst of all,we briefly introduced upconversion nanomaterials and focused on their applications in fluorescence sensing.And then we discussed fluorescence sensor arrays,including the concept of sensor arrays,the application of fluorescence sensor arrays,the challenges and opportunities we faced.Finally,we elaborated the research content,research significance and innovation of our work.Chapter 2 Design of single-component multifunctional sensor array based on upconversion fluorescence and its sensing of antioxidantsIn this chapter,we first synthesized multiplexing UCNPs with three different emission peaks and incubated them with dopamine(DA)to make DA self-polymerize to produce a polydopamine(PDA)layer and coat it on the surface of UCNPs.And the PDA layer could quench("turns off")the three different fluorescence emission peaks of UCNPs through fluorescence resonance energy transfer(FRET)effect.Based on the fact,a novel single-component nanoprobe UCNPs@PDA is created,which can detect the antioxidant that prevents the formation of PDA.Therefore,the UCNPs fluorescence is "turned on" for pattern recognition of antioxidants.Here we creatively use the three fluorescence emission peaks of UCNPs as the sensing unit,and in this way we only need one kind of UCNPs as the material of the sensing element.This is a novel design strategy that reduced the number of sensing materials and achieved the identification of 5 kinds of antioxidants and chiral cysteine enantiomers.Chapter 3 pH regulated PAA/UCNPs-Cu²⁺ fluorescence sensor array for biological thiols detectionIn this chapter,we prepared a core shell structure UCNPs with super bright fluorescence,and constructed the PAA/UCNPs sensor by modifying polyacrylic acid(PAA)on the surface of UCNPs.First,Cu²⁺ can easily combine with the carboxyl of PAA to form a copper carboxylate complex to quench the fluorescence of UCNPs.In addition,the PAA/UCNPs sensor shows different fluorescence responses to Cu²⁺under different pH conditions.We creatively proposed a fluorescence pattern recognition array sensor PAA/UCNPs-Cu²⁺ based on pH regulation.Only by changing the pH value of the buffer system and using one single material as the sensing element,we can realize the discrimination of 5 biothiols.And we can analysis the concentration of homocysteine in the actual sample,which provided a solution to determine whether the human body suffers from homocysteinuria accurately.