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The hypoxic region microenvironment reduces the susceptibility of the cancer cells to radiotherapy and anticancer drugs of the solid tumors. However, the reduced oxygen surroundings provide an appreciable habitat for anaerobic bacteria to colonize and proliferate. Herein, we present a biocompatible bacteriabased system that can deliver poly(lactic-co-glycolic acid)(PLGA) nanoparticles(PLGA NPs) specifically targeting into solid tumor to achieve precision imaging and treatment. In our strategy, anaerobic bacterium Bifidobacterium longum (B. longum) that colonizes selectively in hypoxic regions of animal body was successfully used as a vehicle to conjugate with PLGA NPs and transported into solid tumors. To improve the efficacy and specificity of tumor therapy, low-boiling point perfluorohexane (PFH) liquid was wrapped in the core of PLGA NPs (PFH/PLGA NPs), which could increase the deposition of energy by affecting the acoustic environment of the tumor and destroy cells after liquid-gas phase transition during High Intensity Focused Ultrasound (HIFU) irradiation. This strategy shows an effective diagnosis and treatment integration for giving stronger imaging, longer retention period and more effective tumor therapy. • Bifidobacterium was conjugated with nanoparticles by carbodiimide method, and the biological activity of Bifidobacterium was not affected. • In vitro experiments demonstrated high efficient and stable binding efficiencies. • In vivo tumor targeting showed stronger fluorescence signal and longer retention time, achieving precision imaging. • In vivo precision targeted treatment showed more therapeutic effect. [ABSTRACT FROM AUTHOR]

In this work, a dual-mode immunoassay to detect Ochratoxin A (OTA) was developed relied on p -nitrophenyl phosphate (PNPP) and 2-aminoterephthalic acid (PTA-NH 2). This proposed immunoassay based on microplate immunoenzyme technique used alkaline phosphatase (ALP) as a label for forming immune complexes. The ALP was used to catalyze the dephosphorization of PNPP to generate yellow p -nitrophenol (PNP). Since the absorption wavelength of PNP overlapped with the fluorescence emission of PTA-NH 2 , the fluorescence of PTA-NH 2 can be quenched by PNP. The color of PNP and the fluorescence of PTA-NH 2 were used as double signals to detect OTA. In this dual-mode immunoassay, the limit of detection (LOD) and the linear detection range of fluorescence mode were 0.57 ng/mL (about 0.57 μg/kg) and 1.56–50.00 ng/mL (about 1.56–50.00 μg/kg), respectively. For absorbance mode, the LOD and linear range were 0.07 ng/mL (about 0.07 μg/kg) and 0.39–25.00 ng/mL (about 0.39–25.00 μg/kg), respectively. Both detection modes showed good selectivity for OTA. The recoveries rates of fluorescence mode and absorption mode in maize flours were 91.80–128.85% and 100.10–114.00%, respectively. • The dual-mode immunoassay was developed based on PNPP and PTA-NH 2. • This assay based on microplate immunoenzyme technique used ALP as a label for forming immune complexes. • The mutual verification of the two modes improved the accuracy of analysis method. • The dual-mode immunoassay had a wide linear range and low LOD. [ABSTRACT FROM AUTHOR]