Controllable Synthesis And Application Of Micellar Nanoparticles Based On SiO₂

It is well known that the quantitative detection of cysteine?Cys?in the human body is of great significance for health monitoring and disease prediction.Compared with various reported analytical methods,fluorescent methods have attracted much more attention due to its fast test speed,low cost,high sensitivity and relative operational simplicity.However,most of the organic fluorescent probes exhibited the disadvantages of low fluorescence quantum yield,weak photobleaching resistance,narrow excitation range,and poor solubility in aqueous solutions.In comparison,SiO₂ cross-linked micellar nanoparticles?SCMNPs?possessed excellent mesostructured hydrophobic cores,which can be multi-functionalized with more organic and medical substances for online monitoring and in vivo treatment.Therefore,the design and synthesis of SiO₂-based nano-sensors with ultra-small size is critical.In this paper,SCMNPs were synthesized by using F127 triblock copolymer as a template and using tetraethyl-orthosilicate?TEOS?and TEOS doped with aluminum sec-butoxide?ASB?as precursors.The application of fluorescent SCMNPs in Cys detection and the excellent characteristics of ASB-doped SCMNPs themselves were investigated.The details are as follows:1.Three organic dyes?Fluorescein derivative?FCD?,Coumarin derivative?HCE?and Rhodamine B?RhB??were coated in the hydrophobic core of SCMNPs.Multiple dye-doped SCMNPs?MD-SCMNPs?were designed and synthesized to achieve Cys fluorescence sensing in aqueous media and living cells.FCD reacted with Cys and exhibited green fluorescence“turn-on”in the core of MD-SCMNPs.This green-light-emitting sensing product may cause‘‘step by step”fluorescent resonance energy transfer?FRET?from HCE to the sensing product and then to RhB.Based on the FRET process in the core,MD-SCMNPs can quantitatively detect Cys by a colour change with a low limit of detection?LOD?of 0.3 uM in living cells.Furthermore,MD-SCMNPs exhibited ultra-small size?¹2 nm?and excellent dispersity and biocompatibility,which could potentially be used as a visualized Cys sensor for health monitoring and disease prediction in the human body.2.ASB was incorporated into the SiO₂ framework,and a new gel framework enhancement method was used to design and synthesize SCMNPs with a changed hydrophobic core environment.We found the effect of the swelling agent mesitylene?TMB?content on the particle size of silica-alumina hybrid micellar nanoparticles synthesized with different silicon-aluminum volume ratios.Subsequently,the hybrid nanoparticles were calcined to obtain a mesoporous material with a large specific surface area.The obtained silica-alumina hybrid micellar nanoparticles hold ultra-small particle size?¹0 nm?,large BET specific surface area?1186.64 m²/g?,excellent thermal stability,uniform morphology,and superior dispersibility,cheap raw materials,easy synthesis and so on.The ultra-small particle size of the particle is clearly below the renal clearance threshold,making it a promising nanocarrier.In addition,the large BET specific surface area of this porous nanoparticle make it potentially useful in the field of gas adsorption and separation.It is worth mentioning that,the silica-alumina hybrid shell changes the environment around the organic dye in the hydrophobic core,which has great significance for enhancing the fluorescence quantum yield of organic dyes.