Preparation And Application Of Optoacoustic/near-infrared-â…¡ Fluorescent Dual-mode Probes With Tricyanofuran As Acceptor

Efficient non-invasive detection of in situ biomarkers is of great significance for accurate early diagnosis and therapeutic evaluation of diseases.Activatable optoacoustic/near-infrared II（NIR-II）fluorescent dual-mode probes that respond to biomarkers can combine the advantages of optoacoustic imaging and NIR-II fluorescence imaging to better assess pathological states,showing great application potential.In this paper,two activatable optoacoustic/NIR-II fluorescent dual-mode probes have been designed and prepared using tricyanofuran as the receptor,and the spectral responses of the probes to related biomarkers and imaging application have been investigated.The main contents are as follows:（1）A hydrogen peroxide（H₂O₂）responsive optoacoustic/NIR-II fluorescent dual-mode probe based on tricyanofuran has been designed and synthesized.The chromophore TC-NN is prepared by introducing piperazine into the center of heptamethrin tricyanofurancyanine dye,which effectively alleviates the phenomenon of aggregation induced fluorescence quenching（ACQ）.The obtained chromophore TC-NN has the maximum absorption at 755 nm and the fluorescence emission range at 920-1020 nm.The probe TC-H₂O₂ is synthesized by introducing the nitrophenyloxoacetamide group as the recognition group and fluorescence quenching group of H₂O₂.The reaction of probe TC-H₂O₂ with H₂O₂ promotes the departure of nitrophenyloxoacetamide group,and thus releasing the chromophore.Due to the disappearance of photoinduced electron transfer（PET）effect from TC-NN to nitrophenyloxoacetamide group,the released chromophore absorption red-shifts,and then the relative optoacoustic signal enhances with strong fluorescence emission in the range of 920-1020 nm.Furthermore,the mouse model of isoniazid-induced liver injury is established,and the probe TC-H₂O₂ has been applied to detect and image the in situ H₂O₂ in isoniazid-induced liver injury.（2）A tricyanofuran receptor-based aminopeptidase N（APN）responsive optoacoustic/NIR-II fluorescent dual-mode probe has been designed and synthesized.A donor-acceptor（D-A）dye THCy-NH₂ has been synthesized by Knoevenagel condensation with aminoxanthene as the donor and tricyanofuran as the acceptor.The dye has the absorption maximum at 795 nm and fluorescence emission range at 920-1050 nm.The molecular probe THCy-APN is obtained after introducing L-alanine as APN recognition group and fluorescence quenching group.Then,THCy-APN is complexed with bovine serum albumin（BSA）to form the nanoprobe THCy-APN@BSA,which effectively improved the water solubility and biocompatibility.The enzymatic reaction of THcy-APN and APN transforms the probe into THCy-NH₂,which restores the intramolecular charge transfer（ICT）from aminoxanthene to tricyanofuran,resulting in absorption red-shift,increased absorbance,enhancement of optoacoustic signal and significant enhancement of fluorescence in the 920-1050 nm range.Finally,the mouse model of subcutaneous tumor and lymph node metastasis is established,and the nanoprobe THCy-APN@BSA is successfully applied to image and locate of orthotopic tumor and lymph node metastasis.