November 15, 2019 by admin 0 Comments

Development of an effective sample transfer device for biomarker detection in nasal secretions

Authors
Young Ju Lee (a), Jae-Chul Lee (b), Young Gyu Eun (c), Gi-Ja Lee (a)
Abstract
Nasal secretions (NS) reflect inflammatory activity of the nasal mucosa and thus can be utilized for disease diagnosis and determining treatment effects in Allergic rhinitis (AR). However, non-standardized collection of samples can affect the measured concentration of inflammatory biomarker in NS. In this study, we aimed to develop and evaluate new devices capable of standardizing the collection, storage, and preprocessing methods of NS samples. First, we chose the best swab as polyester (PE) and selected a stimulation method, twirling for 10 s at 1 Hz, to efficiently release AR biomarkers from a PE swab. Storage of sample solutions at −20 °C was optimal for the stability of biomarkers for the detection of AR. The new swab sample transfer device showed excellent concentration recovery efficiency (90–100%) for tryptase (Trp) and eosinophil cationic protein (ECP) without crosstalk between the two biomarkers. Finally, we compared the concentration of Trp in human NS samples of AR patients (n = 6) pre-processed by the new device with that by centrifuge as a standard method. As a result, the concentrations of Trp in NS were very similar in both groups. Therefore, this device can be utilized as an effective sample transfer and pre-processing device for point-of-care testing of AR.

May 10, 2018 by admin 0 Comments

A hook effect-free immunochromatographic assay (HEF-ICA) for measuring the C-reactive protein concentration in one drop of human serum

Authors
Jusung Oh ¹, *, Hyou-Arm Joung ², *, Hyung Soo Han ³, Jong Kun Kim ⁴, and Min-Gon Kim ¹
Abstract
The immunochromatographic (ICA) assay is a highly promising platform for rapid and simple detection of C-reactive protein (CRP) which is an indicator of the different phases of various diseases, as well as of inflammation and infection. However, the hook effect in the ICA assay limits the quantification of CRP levels at high CRP concentrations. Methods: In this study, we developed a hook effect-free immunochromatographic assay (HEF-ICA) to detect CRP over a wide concentration range. The hook effect results from the simultaneous reaction of an excess target antigens with both immobilized and labeled antibodies respectively. To reduce the potential occurrence of this simultaneous reaction, we separated the migration of the target antigen and gold nanoparticle (AuNP)-labeled antibodies on a nitrocellulose membrane and analyzed the time profiles by modifying the ICA structure. Results: The signal intensity of HEF-ICA was saturated at high CRP concentrations, without decreasing. The titration curve of HEF-ICA was adjusted with the Hill equation, and HEF-ICA was performed with the following parameters: limit of detection, 43 ng mL-1; dynamic range, 119 ng mL-1 to 100 µg mL-1. The accuracy of the newly developed assay was evaluated using 33 clinical samples via comparison with a clinical chemistry analyzer. Conclusion: HEF-ICA enabled the measurement of a wide range of CRP concentrations without the hook effect, and was suitable for point-of-care testing with fingertip blood sampling, as only a minute sample volume (2.5 µL) was required.