A Highly Sensitive Immunochromatographic Strip Test for Rapid and Quantitative Detection of Saikosaponin d

Abstract

A quantitative lateral-flow immunoassay using gold nanoparticles (AuNPs) conjugated with a monoclonal antibody (MAb) against saikosaponin d (SSd) was developed for the analysis of SSd. The AuNPs were prepared in our laboratory. The AuNPs were polyhedral, with an average diameter of approximately 18 nm. We used the conjugation between AuNPs and MAbs against SSd to prepare immunochromatographic strips (ICSs). For the quantitative experiment, the strips with the test results were scanned using a membrane strip reader, and a detection curve (regression equation, y = −0.113ln(x) + 1.5451, R2 = 0.983), representing the averages of the scanned data, was obtained. This curve was linear from 96 ng/mL to 150 μg/mL, and the IC50 value was 10.39 μg/mL. In this study, we bring the concept of POCT (point-of-care testing) to the measurement of TCM compounds, and this is the first report of quantitative detection of SSd by an ICS.

A Novel Surface-Exposed Polypeptide Is Successfully Employed as a Target for Developing a Prototype One-Step Immunochromatographic Strip for Specific and Sensitive Direct Detection of Staphylococcus aureus Causing Neonatal Sepsis

“…This was avoided in the current study and we could directly test blood samples without prior treatment which would save time and effort. The designed strip had reaction time of 10-15 min which is similar to those described in previous studies [7,67]. Another study designed ICS for S. aureus detection in respiratory samples [58]; although direct sample detection was possible, the detection limit was too high 10 6 CFU/mL and the reaction toward S. epidermidis was not evaluated, which is a major blood contaminant in neonatal sepsis and can easily cross-react with antibodies to S. aureus antigens.…”

Lateral flow immunoassay for small-molecules detection in phytoproducts: a review

“…The assay commences when the liquid containing the analyte of interest flows through the strip after sample application. The sets of the strip can be provided with the cassette, which contains the sample loading opening that is connected to the sample pad and read-out opening [37][38][39][40][41][42][43]. However, the cassette is not required in certain assays.…”

“…The selection of these reactions depends on the structure of the target molecule. Considering that the reactive aldehyde is easily formed at the vicinal diol of the sugar part, which readily reacts with the amine group of the protein carrier, the sodium periodate reaction is typically preferred in the conjugation of sugar-containing compounds [37,39,42,51,[89][90][91][92][93][94]. However, the cross-reaction of the antibody against the aglycone of the glycosides should be considered when the antigen is prepared by this reaction.…”

Tailor-Made Immunochromatographic Test for the Detection of Multiple 17α-Methylated Anabolics in Dietary Supplements

“…Due to the ease of use and commercial attractiveness of immunochromatographic assays [ 11 ], research and development in this area has expanded considerably. A wide range of analytes including viruses (e.g., hepatitis B [ 12 ], HIV [ 13 ], SARS-CoV-2 [ 14 ]), bacteria (e.g., Helicobacter pylori [ 15 ], Staphylococcus aureus [ 16 ], Salmonella [ 17 ]), toxins [ 18 , 19 , 20 ], pesticides [ 21 ], cancer markers [ 22 , 23 ], antibiotics [ 24 , 25 ], drugs [ 26 , 27 ], terpenes [ 28 ] and steroids [ 29 , 30 , 31 , 32 , 33 ] have been used to construct useful immunochromatographic assays.…”