Multicolor Chemiluminescence Hydrogels

The luminescence caused by chemical reactions is called chemiluminescence(CL).When CL is applied to analysis and detection,there is no photobleaching and phototoxicity,and the background signal is low and sensitive because there is no interference of Rayleigh scattering and Raman scattering.Luminol(LUM),as the most commonly used water-soluble chemiluminescent reagent,is widely used in the fields of biological detection,biological imaging and photodynamic therapy due to its good biocompatibility and high quantum yield.However,LUM is a typical flash monochromatic light-emitting reagent,which often leads to poor analysis accuracy and limits its wider application.In order to expand the wavelength range of CL,most of the reported work is to use the process of chemiluminescence resonance energy transfer(CRET)to redshift the wavelength of CL.However,the reported CRET process is usually limited to a one-step energy transfer process with low efficiency and low intensity and flash CL,and the covalent synthesis modification method is often expensive and complex.For a long time,high intensity and long-lasting "glow-type"multicolor CL has been the goal pursued in the field of CL.Herein,we prepared a class of luminol-based high-intensity long-lasting multicolor CL hydrogels under mild conditions,and studied their CL-related properties and mechanism analysis in detail.The main research contents are as follows:1.We first used a simple LUM-Tris-Co2+chemiluminescent system as a model system,and proved that ?-cyclodextrin(?-CD)assembly can enhance the chemiluminescent intensity of the system,and achieved high-efficiency cascaded CRET through the dynamic assembly of ?-CD,LUM and fluorescent dyes in aqueous solution.Then,the mechanism of ?-CD assembly is further explored:?-CD combines with chemiluminescent reagents and fluorescent dyes to form dynamic assemblies,which can shorten the distance between the contained luminescent intermediates and fluorescent dyes,and make them properly arranged for effective orientation,which greatly improves the CRET efficiency between the luminescent intermediates and fluorescent dyes,thus realizing the multi-step cascade CRET.2.By choosing suitable fluorescent dyes and optimizing the reaction conditions,we can make the dynamic ?-CD nano assembled CL system emit high intensity CL with adjustable wavelength in the range of 410-610 nm.The efficiency of the cascade CRET can reach 92%,which is comparable with the cascade Furster resonance energy transfer(FRET)systems based on covalently linked donors and acceptors.3.In order to prepare high-intensity long-lasting and multicolor CL hydrogels,we use hydroxypropyl methyl cellulose(HPMC)as thickener to slow the diffusion of hydrogen peroxide(to elongate the CL emission),and use Ca(OH)2 solid(a low solubility strong base)as buffer to maintain the pH in the optimal range for the CL reaction.Thus,the efficient cascade CRET mechanism and the long-lasting glow CL mechanism are perfectly coupled,making the high-intensity,long-lasting multicolor CL visible to the naked eye for up to 22 hours.4.Our work is simple,low-cost,environmentally friendly,and enables high intensity and long-lasting multicolor CL in aqueous solution,which can replace peroxyoxalate CL system.We use high-intensity,long-lasting multicolor CL hydrogels to prepare "painting" ink and to produce multi-color 3D code for information storage and conversion,and replace fluorescent rods in cold light source and decoration fields.In general,the high intensity long-lasting multicolor CL hydrogels based on LUM have broad application prospects in cold light sources,biological detection,biosensors,imaging and encryption.In addition to chemiluminescent materials,organic fluorescent materials have been widely used due to their advantages of high fluorescence intensity,stability,easy structure modification,narrow spectral peak,high sensitivity and good selectivity.The fourth chapter mainly introduces the work of two kinds of organic fluorescent materials,which mainly involves the molecular structure design,synthesis,structure characterization and property exploration of fluorescent materials.