Synthesis Of Probes Based On Indole Hemicyanine And Their Detection Of Enzyme Biomarkers

Indole hemicyanine is usually employed to design optical probes for detecting enzyme biomarkers,owing to its long absorption and emission wavelength.In this study,two probes based on indole hemicyanine have been designed,and their applications in detection for alkaline phosphatase(ALP)and NAD(P)H:quinone oxidoreductase-1(NQO1)have been explored.The main contents are as follows:(1)The ALP-responsive near-infrared fluorescent probe X-DPA-Phos based on benzoindole hemicyanine has been designed and synthesized.Its chemical structure has been characterized.Then the response capability to ALP of fluorescent probe X-DPA-Phos has been investigated.With the enzymatic reaction by ALP,the phosphate group of X-DPA-Phos is cleaved,and therefore the near-infrared fluorescence signal at 765 nm of the resultant fluorophore X-DPA-OH appears upon 700 nm excitation.Thus,the fluorescence detection of ALP can be achieved and the limit of detection is determined to be 8.26 U/L.(2)The NQO1-responsive optoacoustic(OA)probe TPA-X-Q based on indole hemicyanine has been designed and sythesized.Its chemical structure has been characterized.And the reponse capability to NQO1 of OA probe TPA-X-Q has been investigated.In the presence of NQO1,the quinone propionate group of TPA-X-Q is cleaved,and therefore the probe is transformed into the chromophore TPA-X-OH,consequently evident OA signal is generated.The limit of detection is determined to be 0.19 μg/m L.Furthermore,the probe TPA-X-Q displays several advantages,such as good selectivity,excellent photostability and low biotoxicity.Finally,the probe has been utilized to detect and image the overexpressed NQO1 in the breast cancer-bearing mouse model.Orthogonal-view three-dimensional(3D)images can also be obtained by using multispectral optoacoustic tomography(MSOT),and thus precise localization of the breast cancer tumors can be achieved.