Constructions Of The Fluorescent Probes For Selenol Compounds Detection And Their Applictions

Selenium is one of the necessary trace elements in human body and takes part in metabolism by form of selenol.It is related to many diseases and physiological process and could prevent from many cancer diseases.Therefore,it is of great significance to the detect selenol and to make us realize the anti-cancer mechanism of selenol.Selenol doesn't only exist in eucaryon,it is also found in prokaryote(such as Escherichia coli).However,not all prokaryote has selenium protease or could transfer inorganic selenium to organic selenol,only a few of prokaryote equips this feature.Besides,seleonl also exists in some plants such as tea and rice.They absorb the inorganic selenium in the soil and storage in the edible part of plants,thus,the detection of selenol could provide a method to supervise the content in selenium-rich food.In conclusion,the detection of selenol is of great importance for acknowledging the metabolism of human body,identifying the bacteria and monitoring the safety of food.Due to the importance of selenol,the methods for the detection of selenol are investigated,including high performance liquid chromatography(HPLC)and small-molecule fluorescent probe method.However,these methods have some disadvantages,such as expensive instrument,poor biocompatibility and high detection limit.Therefore,a new sensitive and biocompatible method for the detection of selenitol need to be explored.In this paper,we synthesized three kinds of nanoparticles based on the detection of selenoalcohols and realized their biological and food applications.Specific work contents are mainly divided into the following three parts:1.A novel gold nanoprobe was designed to detect selenol sensitively and specifically.Nile Blue combines with glutathione to form sulfydryl containing dye molecules(NB-GSH),then NB-GSH is modified to the surface of gold nanoparticles by Au-S.By the unique FRET properties of the gold nanoparticles,the entire system is in a state of fluorescence quenching.Compared with sulfydryl,selenol has better nucleophilicity with gold nanoparticles.Therefore,when selenol appears,the sulfydryl compounds modified on the gold nanoparticles will be replaced to form a more stable Au-Se bond,and the NB-GSH falls off to recover the fluorescence.The nanoprobe gets excellent selectivity,sensitivity with detection limit of 9.5 n M.It could be further applied to the imaging and detection of endogenous and exogenous selenol in Hep G2 cells.At the same time,selenol content in selenium-rich tea and selenium-rich rice was tested to realize its application in food testing.2.We designed a new kind of nanomaterials based on the gold nanorod,which realized the specific detection of selenol by the specific recognition of the sulfonamide bond of selenol.Nile Blue fluorescent dye molecules containing sulfonamide bonds were combined with thiol pyrimidines,then it is modified on the surface of gold nanorods to form GNRs-SH-NB.The gold nanorods have FRET properties,no fluorescence is generated in GNRs-SH-NB.In the presence of selenol,the sulfonamide bond is cracked by selenol,the fluorescence recover.GNRs-SH-NB has excellent specificity and sensitivity to selenol with detection limit of 11.36 n M.Meanwhile,it can also achieve the identification of selenol-containing E.coli,among the bacteria and fungi.Furthermore,GNRs-SH-NB can also detect E.coli on the surface of meat,milk and egg shells,so as to realize its application in food.After that,we further studied its antibacterial effect,and the antibacterial test showed that the nanomaterial could achieve excellent inhibition rate to E.coli,and it could become a new nanomaterial to identify and inhibit Escherichia coli.3.Selenol detection nanoprobe is designed based on the self-assembly nanoparticles,by using the disulfide bond(S-S)to combine cell penetrating peptides(R8)and antibacterial and anticancer peptide Melittin(Melittin),we get a new kind of two hydrophilic peptide,then we use the fluore BODIPY to form the nanoparticles R8-S2-Melittin@BODIPY.At this point,the fluorescent molecules are wrapped inside the nanoparticles,so it is difficult for us to detect the fluorescence.When selenol appears,due to the nucleophilicity of selenol,S-S bond can be cleated,and BODIPY molecules are released to generate fluorescenc.R8-S2-Melittin@BODIPY has good selectivity and sensitivity to selenol with detection limit of 3.34 n M.In bacteriostatic experiments,self-assembled nanoparticles had better bacteriostatic properties than Melittin.Moreover,R8-S2-Melittin@BODIPY equipped the low cytotoxicity and could be further applied in cell imaging and treatment.In conclusion,we design and obtain 3 novel kinds of nanoprobe,the could realize the specific response to selenol and get the low detection of limit.These nanoprobe have great potential in biological and food detection and could be the first time to identify E.coli by detecting selenol.These reeasrch could provide a new thought to realize the selenol detection and further applied in many fields such as food detection and trace the metabolism of selenol in body.