An Automated Micro-Total Immunoassay System for Measuring Cancer-Associated α2,3-linked Sialyl N-Glycan-Carrying Prostate-Specific Antigen May Improve the Accuracy of Prostate Cancer Diagnosis.

The low specificity of the prostate-specific antigen (PSA) for early detection of prostate cancer (PCa) is a major issue worldwide. The aim of this study to examine whether the serum PCa-associated α2,3-linked sialyl N-glycan-carrying PSA (S2,3PSA) ratio measured by automated micro-total immunoassay systems (µTAS system) can be applied as a diagnostic marker of PCa. The µTAS system can utilize affinity-based separation involving noncovalent interaction between the immunocomplex of S2,3PSA and Maackia amurensis lectin to simultaneously determine concentrations of free PSA and S2,3PSA. To validate quantitative performance, both recombinant S2,3PSA and benign-associated α2,6-linked sialyl N-glycan-carrying PSA (S2,6PSA) purified from culture supernatant of PSA cDNA transiently-transfected Chinese hamster ovary (CHO)-K1 cells were used as standard protein. Between 2007 and 2016, fifty patients with biopsy-proven PCa were pair-matched for age and PSA levels, with the same number of benign prostatic hyperplasia (BPH) patients used to validate the diagnostic performance of serum S2,3PSA ratio. A recombinant S2,3PSA- and S2,6PSA-spiked sample was clearly discriminated by µTAS system. Limit of detection of S2,3PSA was 0.05 ng/mL and coefficient variation was less than 3.1%. The area under the curve (AUC) for detection of PCa for the S2,3PSA ratio (%S2,3PSA) with cutoff value 43.85% (AUC; 0.8340) was much superior to total PSA (AUC; 0.5062) using validation sample set. Although the present results are preliminary, the newly developed µTAS platform for measuring %S2,3PSA can achieve the required assay performance specifications for use in the practical and clinical setting and may improve the accuracy of PCa diagnosis. Additional validation studies are warranted.

Development of on-chip fully automated immunoassay system "µTASWako i30" to measure the changes in glycosylation profiles of alpha-fetoprotein in patients with hepatocellular carcinoma.

Glycosylation profiles significantly change during oncogenesis. Aberrant glycosylation can be used as a cancer biomarker in clinical settings. Different glycoforms can be separately detected using lectin affinity electrophoresis and lectin array-based methods. However, most methodologies and procedures need experienced technique to perform the assays and expertise to interpret the results. To apply glycomarkers for clinical practice, a robust assay system with an easy-to-use workflow is required. Wako's µTASWako i30, a fully automated immunoanalyzer, was developed for in vitro diagnostics based on microfluidic technology. It utilizes the principles of liquid-phase binding assay, where immunoreactions are performed in a liquid phase, and electrokinetic analyte transport assay. Capillary electrophoresis on microfluidic chip has enabled the detection of different glycoform types of alpha-fetoprotein (AFP), a serum biomarker for hepatocellular carcinoma. AFP with altered glycosylation can be separated based on the reactivity to Lens culinaris agglutinin on electrophoresis. The glycoform AFP-L3 was reportedly more specific in hepatocellular carcinoma. This assay system can provide a high sensitivity and rapid results in 9 min. The test results for ratio of AFP-L3 to total AFP using µTASWako i30 are correlated with those of conventional methodology. The µTASWako assay system and the technology can be utilized for glycosylation analysis in the postgenomic era.

[Evaluation of a new, microfluidic chip-based immunoassay for measurement of AFP-L3].

PURPOSE: AFP-L3 is an isoform of a-fetoprotein which has a fucosylated carbohydrate chain, and the fraction of AFP-L3/total AFP (AFP-L3%) specifically increases in hepatocellular carcinoma (HCC) patients and is widely used for screening and prognosis of HCC. The newly developed microTAS method which combines microchip electrophoresis and lectin affinity electrophoresis can rapidly provide AFP-L3% and total AFP measurements simultaneously at higher sensitivity. Here, we evaluated the system to know its analytical performance and clinical utility. METHOD: Fully automated immunoanalyzer, microTASWako i30 which utilizes Liquid-phase Binding Assay-Electrokinetic Analyte Transport Assay (LBA-EATA method) as the assay principle was employed for the measurement of total AFP and AFP-L3%. We evaluated detection sensitivity, precision, accuracy, and correlation of the method. RESULTS: The detection sensitivity was 0.3 ng/ml for both AFP-L1 and L3. The accuracy of the assay was 91.3-105.0% for total AFP. The precision of the assay was CV 1.9% at 2 ng/ml of total AFP, and CV 1.3% for 10% of AFP-L3% at 20ng/ml of total AFP. The microTAS method showed good correlation with the lectin affinity electrophoresis (AFP-L3 Test Wako) and the LBA methods (LBA Wako AFP-L3 on LiBASys) methods, giving correlation coefficient (r) of 0.988 and 0.988, respectively. The microTAS immunoreaction assay time and the total assay time including chip preparation were 1 and 9 min, respectively. CONCLUSION: Since the microchip assay is rapid and highly sensitive, it should have better clinical utility than the current methods.

[Fully automated immunoassay system utilizing microchip electrophoresis].

Application of microTAS (micro Total Analysis Systems) technologies utilizing chips with microfluidic channels to clinical diagnostic testing has drawn a lot of attention since it is expected to contribute to shortening reaction time, reduction of reagent/sample consumption, reducing instrument size, and other advantages of microchip electrophoresis. We have developed a fully automated immunoassay system by employing isotachophoresis followed by capillary gel electrophoresis for immunoreaction and B/F separation in microfluidic channels on polymer microchips. Laser-Induced Fluorescence (LIF) was used for detection of the sandwich immunocomplex composed of DNA-conjugate antibody, antigen and fluorescent dye-conjugated antibody. An immunoassay for PIVKA II was demonstrated on this new microTAS system utilizing the DNA-conjugated anti PIVKA II antibody and the fluorescent-dye labeled anti-prothrombin antibody. The resulting assay showed good assay performance with high sensitivity (LOD = 5mAU/mL), good reproducibility(CV = 1.0 - 5.7%) and good correlation with the commercially available PIVKA II assay kit (regression curve of y = 1.04x + 11.1, r = 0.991). The assay turn around time (TAT) was about 9 min. The PIVKA II assay will be useful for the diagnosis and prognosis of hepatocellular carcinoma.

Automated immunoassay system for AFP-L3% using on-chip electrokinetic reaction and separation by affinity electrophoresis.

Implementation of the on-chip immunoassay for alpha-fetoprotein (AFP)-L3% was achieved using a fully automated microfluidic instrument platform that will prepare the chip and run the assay with a total assay time of less than 10min. Reagent/sample mixing, concentration, and reaction in microfluidic channels occur by the electrokinetic analyte transport assay (EATA) technique, enabling the integration of all assay steps on-chip. The determination of AFP-L3%, a biomarker for hepatocellular carcinoma, was achieved by the presence of Lens culinaris agglutinin in the separation channel, causing separation of the fucosylated isoform, AFP-L3, from the nonfucosylated AFP-L1 by lectin affinity electrophoresis. Laser-induced-fluorescence (LIF) detection was used to quantitate the labeled immunocomplexes. The limit of detection (LOD) was 0.1ng/ml AFP, and assay precision of less than 2% coefficient of variation (CV) was obtained for quantitation from 24 to 922ng/ml total AFP in spiked serum samples. Assay precision of less than 3% CV was obtained for AFP-L3% measurements from 8.5 to 81%. Furthermore, good correlation of test results for 68 patient serum samples with a commercially available reference method (LiBASys assay for AFP-L3%) was obtained, with r(2)=0.981 and slope=1.03.