Novel Fluorescence/Surface Plasmon Resonance Optical Biosensing Strategies For The Detection Of Bioactive Molecules

The optical biosensor,which has advantages of simple,rapid,high sensitivity,good selectivity,has been widely used in detection and analysis of heavy metals,small molecules,protein and other biological molecules.It has the great research value and scientific significance in diagnosis and treatment of major diseases and food safety monitoring.However,the development of high-performance optical biosensor is still a challenging task.As we all know,the sensor performance,including sensitivity,selectivity,repeatability,accuracy,etc,depends on the physical and chemical properties of the selected signal unit molecules.In view of this,this paper used functional materials,including aggregation induced emission(AIEE)materials and polyaniline nanomaterials,to build a new optical sensing platform for the simple,rapid and high sensitive detection of bioactive molecules.The fluorescent sensor was developed based on enzymatic hydrolysis and intermediate mediated reaction strategies for rapid naked-eye detection of acetylcholinesterase activity and organophosphorus pesticides with high sensitivity and selectivity.AChE can catalyze the hydrolysis of acetylcholine to produce choline,which leads to the aggregation of TPE-M and the generation of high fluorescence signal.When OPs was present,the activity of AChE was inhibited,and the production of choline were not generated or generated less,which lead to fluorescence signal reduced greatly.This strategy has achieved the visual detection of AChE activity and its inhibitors.The detection limit is down to 2.5 mU mL"1 and 0.5 ng mL-1.The universal label-free fluorescent biosensing platform was constructed based on hemin/G-Quadruplex DNAzyme catalytic oxidation ability for the ultrasensitive detection of multiple targets.The functionalized AIE material can react with L-cysteine,which leads to high fluorescence signal.Hemin/G-Quadruplex DNAzyme can catalyze oxidation of L-cysteine to L-cystine,destroyed the reaction between TPE-M and L-cysteine,resulting in the fluorescence signal reduced greatly.When the target miRNA is present,it causes the isothermal exponential amplification cycle reaction.This reaction produced a large amount of hemin/G-Quadruplex DNAzyme,which catalyzes the oxidation of L-cysteine,leading to a significant decrease in fluorescence intensity.This biosensor has achieved the ultrasensitive detection of miRNA.The detection limit is down to 0.1 fM.The universal surface plasmon resonance biosensor was constructed based on HRP-mimicking DNAzyme-catalyzed in situ generation of polyaniline to assist signal amplification for ultrasensitive detection of a series of target,with bleomycin(BLM)as an example.When the present of BLM,the recognition and the subsequent cleavage of DNA probe P1 by BLM switches off the hybridization between P1 and the G-rich DNA probe P2,resulting in less hemin/G-quadruplex complexes and reduced DNA-guided polyaniline deposition on SPR Au disk surface.The SPR angle shift is less.As compared to the case that BLM is absent,significant SPR angle shift is observed.Therefore,ultrasensitive SPR detection of target BLM is realized,with a detection limit down to 0.35 pM,much lower than those reported in literature.