Construction Of Nanoprobes Based On Functional Nanomaterials And Application In The Environmental And Biological Detection

In order to meet the accurate detection of environmental pollution and the accurate analysis of life and health,research in the field of nano-sensors is receiving widespread attention.Nanosensors based on nano-sensitive materials and new sensing technologies have broad application prospects in the fields of environmental detection,biological detection,clinical diagnosis,and food safety.The development of nanomaterial preparation methods and the development of new nanosensor technologies have important theoretical and practical significance.Based on the background above,this work has focused on the research of gold nanoclusters?AuNCs?,carbon quantum dots?CDots?,and metal-organic framework compounds?MOFs?.A series of studies have been conducted around the preparation and sensing applications of these three materials.?1?In this work,a novel fluorescence resonance energy transfer?FRET?-based ratiometric fluorescent probe,carbon dots-gold nanoclusters hybrid?CDots-AuNCs?,was fabricated for selective,sensitive and reliable sensing of dopamine?DA?.This FRET probe is comprised of a two-fluorophore,where carbon dots?CDots?serve as the energy donor and gold nanoclusters?AuNCs?as the acceptor,with dual emission peaks at 420 nm and 610 nm under a single excitation wavelength of 380 nm.The addition of DA to this probe solution resulted in the fluorescence at610 nm quenching,while the blue fluorescence at 420 nm recovering.By monitoring the change of ratiometric fluorescent intensity at 420 and 610 nm,the DA could be detected with the range from 5 to 180 nM and a limit of detection around 2.9 nM.Finally,the developed sensing method was successfully applied to DA determination in serum samples with satisfactory recoveries in the range of 95%–105%.?2?A high sensitivity fluorescent probe for the selective detection of Cu²⁺and Pb²⁺was prepared.The probes were synthesized by electrostatic assembly between the positively charged carbon dots?NCDots?and the negatively charged gold nanoclusters?Au NCs?.Pb²⁺effectively enhanced the fluorescence of AuNCs through the Aggregation-Induced Emission?AIE?effect,Cu²⁺quenched the fluorescence of AuNCs through energy transfer,and the blue emission of NCDots served as a reference signal.This probe has the advantages of simple preparation,high sensitivity and visualization,and the limits of detection for Cu²⁺and Pb²⁺were around 0.15?M and 0.5?M,respectively.Finally,the developed sensing method was successfully applied to the determination of Cu²⁺and Pb²⁺in Yangtze River water.?3?As the high-risk of BPA with low dose,strong requirements have been put forward for the development of high selectivity detection methods for trace amounts of BPA.The fluorescence of FAM was quenched by a photo induced electron transfer?PET?mechanism via the adsorption between FAM-aptamer and Lavoir-Si skeleton structure compound?MIL101?.BPA made the aptamer deconstructed,resulting in the release of FAM-aptamer from MIL101 and the recovery of the fluorescent.This probe has the characteristics of high sensitivity and low cost,and it has been successfully applied to the detection of BPA in Yangtze River water with a limit of detection around2.2 nM.?4?Caspase-3 is a key regulator of apoptosis and its activity may thus serve as a good marker to monitor cell apoptosis.Herein,we prepared a novel,sensitive electrogenerated chemiluminescence?ECL?indicator CDots@ZIF-8/AuNPs for assay of Caspase-3 activity.Carbon dots?CDots?were initially synthesized via a facile microwave method and were then modified with zeolitic imidazolate framework?ZIF-8?nanocrystals followed by loading of AuNPs to fabricate CDots@ZIF-8/AuNPs with enhanced ECL intensity.After modification with streptavidin,the as-prepared hybrid nanocrystals were successfully attached to the electrode through the bridge of peptide substrate?DEVD?,generating ECL.Upon the addition of apoptosis cell lysis solution,the cleavage of the peptide by Caspase-3 can liberate the ECL labels from the surface of electrode,which leads to a decrease of the signal.As a result,the enzyme activity can be evaluated.Apoptotic K562 cells treated with apoptosis inducer and nilotinib are facilely and sensitively detected,suggesting that the biosensor could be applicable in real samples and has great potential for evaluation the apoptosis-related chemotherapeutic effect.Moreover,because of the features of CDots,ZIF-8 and AuNPs,this novel ECL sensing strategy exhibits attractive advantages of environmental benignity,simple performance,high stability,and is expected to be extended to other enzymes and analytes assays.