Construction And Application Of Biochemical Sensor Based On Cyanine Dye

Fluorescent probe is an important analytical method,which has various advantages,such as high sensitivity,good selectivity,noninvasive in vivo imaging,and has been widely used in analytical detection,medical diagnosis and treatment,and other fields.The fluorescent probes based on cyanine are favored by researchers because of its long emission wavelength in the near-infrared region,which is conducive to the research of bioimaging.Based on this state,in this paper,we designed and synthesized three different biosensors based on cyanine dyes,which were used to trap the active substances in vivo,such as leucine aminopeptidase(LAP)and formaldehyde.The main contents are as follows:(1)A novel near infrared fluorescent probe(CY-P)was constructed to monitor leucine aminopeptidase(LAP)in vivo.The probe CY-P is using cyanine dye derivative(CY-OH)as the signal output group,L-leucine residue in dipeptide(Cys-Leu)as the recognition mode.Its structure is also characterized by NMR and HRMS.In the present of LAP,the amide bond in dipeptide is cleavaged by LAP,and a free amino group was released,and then,a further nucleophilic substitution reaction was occured,which trigger the release of CY-OH,and accompany with a significant fluorescence signal change,and realizing the specific recognition of LAP.In this process,CY-P shows various advantages,such as high sensitivity,low detection limit and good water solubility in the near infrared region.Furthermore,the probe CY-P was also successfully used to track endogeous LAP in cancer cells and zebrafish model.(2)Construction of near-infrared fluorescent probe(CY-B)for the detection of formaldehyde(FA).On the basis of cyanine dye,CY-B was synthesized by grafting potassium allyltrifluoroaborate onto CY-OH.Its structure was characterized by NMR and HRMS.Probe CY-B gave a significant fluorescence at 720 nm in the near-infrared region.In the present of FA,the fluorescnece was quenched due to PET effect,which finally realized the recognition of FA.Through relevant tests,CY-B has good selectivity and high sensitivity for formaldehyde detection,which is conducive to the efficient detection of formaldehyde molecules in vivo.(3)Design and synthesize a new prodrug(CY-CPT-Leu)based on leucine aminopeptidase(LAP).The prodrug using the cyanine dye as the fluorescence reporter,L-leucine residue as the trigger moiety,and camptothecin(CPT)as the anticancer drug.We intends to construct CY-CPT-Leu,and expect the prodrug can release the anticancer drug CPT under the trigger of LAP,and finally killing tumor cells in vivo,and take some reference for cancer diagnosis and treatment.