Enhanced performance of a surface plasmon resonance-based immunosensor for the detection of glycocholic acid

A candidate reference measurement procedure for quantification of glycocholic acid in human serum based on isotope dilution liquid chromatography-tandem mass spectrometry

Accurate measurement of serum glycocholic acid (GCA) is crucial for evaluating the activity of chronic hepatitis. Moreover, GCA is a novel identified biomarker for hepatocellular carcinoma. Although some laboratories have used the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to measure GCA in recent years, the problem of potential interference of GCA analogues has not been solved well yet. Neither reference measurement procedures nor reference materials for GCA have been listed in the Joint Committee for Traceability in Laboratory Medicine (JCTLM) database. For standardization of GCA, it is urgent to establish a candidate measurement procedure for GCA. In this study, a candidate reference measurement procedure for the quantification of GCA in human serum based on isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) by a two-step sample pretreatment of protein precipitation and MAX solid-phase extraction was developed and validated. GCA can be completely separated from its structural analogues with gradient elution in 9 min compared with short time gradients published in previous literature by Huang's group. Method validation indicated perfect quantitation precision with intra-day and inter-day values that were ≤1.30% and ≤1.80%, respectively. The method showed excellent linearity with high regression coefficients (R2 > 0.999) over a range of 0.92 ng/g-38.38 μg/g and perfect recoveries at three spiked levels (99.87-100.43%). No interference, matrix effect, and carryover were observed. Moreover, the cRMP was successfully applied to measure GCA in serum samples and compared with two immunoassays in a clinical laboratory. As a candidate reference method, this method can promote a GCA standardization program.

An AgPd NP-based lateral flow immunoassay for simultaneous detection of glycocholic acid and alpha-fetoprotein

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality globally, ranking third in cancer deaths. Early diagnosis of HCC markers is imperative for effective prognosis and treatment. This study explores the utility of glycocholic acid (GCA) and alpha-fetoprotein (AFP) as biomarkers for liver diseases, with a specific focus on their simultaneous detection for enhanced diagnostic and prognostic capabilities. Harnessing the benefits of lateral flow immunoassay (LFIA), such as operational simplicity, speed, and accuracy, we engineered AgPd nanocomposites with antibodies targeting GCA and AFP. Under the optimized conditions, the visual detection limit for GCA was established at 50 ng mL-1 and the cut-off value at 104 ng mL-1. And for AFP, the visual detection limit was 0.1 ng mL-1 and the cut-off value was 500 ng mL-1. The accuracy and feasibility of the strips were validated through the detection of 39 actual serum samples. The results highlight the potential of LFIA as a rapid and effective tool for clinical diagnosis. The developed LFIA method not only demonstrates accuracy and feasibility but also presents a promising avenue for the early diagnosis of hepatocellular carcinoma.

Antibody-receptor bioengineering and its implications in designing bioelectronic devices

Antibodies play a crucial role in the defense mechanism countering pathogens or foreign antigens in eukaryotes. Its potential as an analytical and diagnostic tool has been exploited for over a century. It forms immunocomplexes with a specific antigen, which is the basis of immunoassays and aids in developing potent biosensors. Antibody-based sensors allow for the quick and accurate detection of various analytes. Though classical antibodies have prolonged been used as bioreceptors in biosensors fabrication due to their increased fragility, they have been engineered into more stable fragments with increased exposure of their antigen-binding sites in the recent era. In biosensing, the formats constructed by antibody engineering can enhance the signal since the resistance offered by a conventional antibody is much more than these fragments. Hence, signal amplification can be observed when antibody fragments are utilized as bioreceptors instead of full-length antibodies. We present the first systematic review on engineered antibodies as bioreceptors with the description of their engineering methods. The detection of various target analytes, including small molecules, macromolecules, and cells using antibody-based biosensors, has been discussed. A comparison of the classical polyclonal, monoclonal, and engineered antibodies as bioreceptors to construct highly accurate, sensitive, and specific sensors is also discussed.