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Amantadine is one of the most prescribed antiviral medications. Considering its abuse is life-threatening, monitoring amantadine residues is urgently needed. This study designed a dipstick assay based on lateral flow immunoassay (LFIA) platforms with an indicator range of 50–200 ng/mL. The dipstick consists of four coloured test lines that detect the concentration of amantadine semi-quantitatively in the range of 0–200 ng/mL. The amantadine concentration was categorised as 0–50, 50–100, 100–200, or > 200 ng/mL, depending on the response of the test lines. Furthermore, we measured the amantadine residues in commercial meat samples by this LFIA. The results were highly agreeable with those determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LFIA shows potential for routine monitoring of amantadine in meat products, and the results of this study provide insight into the development of new LFIA devices for use in agricultural industries. [ABSTRACT FROM AUTHOR]

Dihydroartemisinin (DHA) is one of the artemisinin derivatives widely used in artemisinin-based combination therapies (ACTs) for malaria treatment. The availability of a point-of-care device for estimation of DHA quantity would allow a quick quality assessment of the DHA-containing drugs. In this study, 9-O-succinylartemisinin was obtained from microbial fermentation of artemisinin, which was hydrogenated to 9-O-succinyldihydroartemisinin as the hapten for DHA. A monoclonal antibody (mAb), designated as 2G 1 1G 4 , was identified after screening the hybridoma library, which showed 52.3% cross reactivity to artemisinin, but low or no cross reactivity to artesunate, artemether, and several ACTs partner drugs. Based on this mAb, a highly-sensitive, indirect competitive enzyme-linked immunosorbent assay was designed, which showed 50% inhibition concentration of DHA at 1.16 ng/mL, a working range of 0.26–4.87 ng/mL, and limit of detection of 0.18 ng/mL. In addition, a colloidal gold-based lateral flow immunoassay (dipstick) was developed with an indicator range (indicating sensitivity) of 50–100 ng/mL. This dipstick was evaluated for determination of DHA contents in commercial drugs and the results were highly agreeable with those determined by high-performance liquid chromatography. [ABSTRACT FROM AUTHOR]

6-Benzylaminopurine (6-BA), a cytokinin plant growth regulator, has been banned for use in bean sprout production in China. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed with a specific monoclonal antibody (mAb 3E5). The assay showed a half-maximum inhibition concentration (IC 50 ) and detection range of 18.9 ng/mL and 3.6–106 ng/mL, respectively. Recoveries of 6-BA spiked in home cultured bean sprout samples averaged from 75% to 89% with a correlation coefficient (R 2 ) of 0.998 between the results determined by icELISA and those by liquid chromatography–electrospray ionization quadrupole Orbitrap mass spectrometry (LC–ESI-MS). LC–ESI-MS showed that 6-BA had been partially metabolized to 6-benzylaminopurine riboside (6-BAR) in the positive samples. The content of 6-BA determined by icELISA was about 5–70 times higher than that of LC–ESI-MS because mAb 3E5 had 315% cross-reactivity with 6-BAR. Such icELISA being ultra-sensitive to 6-BAR would allow quick monitoring of 6-BA by detecting 6-BAR as a potential biomarker. [ABSTRACT FROM AUTHOR]