Joel Isanga,Daniel Mukunzi,Yanni Chen,Steven Suryoprabowo,Liqiang Liu,Hua Kuang,Chuanlai Xu
A monoclonal antibody (MAb) was produced against paromomycin and used in the development of an immunoassay and a lateral flow strip test for the detection of paromomycin residues in food matrices. The MAb had 25.1% cross-reactivity with neomycin, but was insensitive to other aminoglycosides. Tested under optimized conditions in 0.01 M phosphate-buffered saline, the half maximum inhibitory concentration (IC50) of the MAb was 0.61 ng/ml for paromomycin and 2.43 ng/ml for neomycin, with results obtained within 90 min. The mean recoveries from spiked food matrices were within the range of 64.56–105.85% for paromomycin and 54.08–100.55% for neomycin. The strip test results for different food matrices were obtained within 5 min and showed visual detection limits of 2.5–20 ng/ml (µg/kg) for paromomycin and 10–30 ng/ml for neomycin. Therefore, the developed immunoassay and strip test can be used in food analysis for routinely monitoring not only paromomycin but also neomycin residues.
Development of rapid and sensitive methods for screening of large number of chemical pollutants with potential genotoxicity is in urgent demands. In this work, we reported a chemical genotoxicity sensor based on the lateral flow strip (LFS) quantification of the 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo). The proposed sensing strategy introduced human 8-oxoguanine DNA glycosylase (hOGG 1) and human apyrimidinic endonuclease (APE 1) to convert 8-oxodGuo to strand break. Then, the DNA conjugated gold nanoparticles (AuNPs) complexes could not be captured on test line (T-line), showing visible red color fading. Additionally, the mean grey value of the optical density in the T-line zone was analyzed by using a mobile phone camera and Image J software to quantify 8-oxodGuo. Under the optimized experimental conditions, the LFS DNA biosensor could detect the lowest concentration of 8-oxodGuo down to 0.2 pmol. To demonstrate its universal applications, in vitro generation of 8-oxodGuo by Rose Bengal under irradiation and Fe 2+ -mediated Fenton reagent were successfully measured. The detection limit of oxidative DNA damage induced by Rose Bengal or Fenton reagent could be down to 0.01 μM or 1 nM Fe 2+ /4 nM H 2 O 2 , respectively. The 10-fold higher sensitivity for Fenton reagent was attributed to much more severe damage than Rose Bengal, producing both DNA strand break and nucleobases conversion. The results demonstrated that the LFS DNA biosensor could detect oxidative DNA damage for the first time, showing its potential application for assessment of the genotoxicity of abundant chemical pollutants.
Biofluid biomarkers, as objective predictors of traumatic brain injury (TBI) pathobiological processes, play an important role in the early detection of TBI. However, the lack of sensitive and rapid detection assays to detect biomarker levels has been an urgent problem. In this study, we devised a novel surface-enhanced Raman scattering (SERS)-based paper lateral flow strip (PLFS) based on gold nanorods (AuNRs) with controlled aspect ratios for the screening and diagnosis of TBI. To improve the sensitivity of the designed device, AuNRs, as the key component of SERS probes, were optimized by controlling the particle morphology, showing great local plasma enhancement. Furthermore, using thionin acetate (THI) as a Raman reporter, the detection performance of PLFS was further improved due to the unique molecular structure of THI. Thus, the constructed PLFS has been demonstrated to be ultrasensitive, with a limit of detection (LOD) reaching ∼10–1 pg·mL–1. Fo r real-world measurements of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) in blood samples, the results monitored by the SERS assay were exactly consistent with those obtained through the traditional enzyme-linked immunosorbent assay (ELISA). The above result demonstrated that the developed SERS-PFLS has extensive application prospects in the screening and diagnosis of TBI in the emergency department as point-of-care testing (POCT) and may further shift the paradigm of TBI patient management and clinical outcome in emergency departments.
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