Evaluation of a method for the simultaneous detection of multiple tumor markers using a multiplex suspension bead array

Early diagnosis of disease using microbead array technology: A review

Early diagnosis of diseases (before they become advanced and incurable) is essential to reduce morbidity and mortality rates. With the advent of novel technologies in clinical laboratory diagnosis, microbead-based arrays have come to be recognized as an efficient approach, that demonstrates useful advantages over traditional assay methods for multiple disease-related biomarkers. Multiplexed microbead assays provide a robust, rapid, specific, and cost-effective approach for high-throughput and simultaneous screening of many different targets. Biomolecular binding interactions occur after applying a biological sample (such as blood plasma, saliva, cerebrospinal fluid etc.) containing the target analyte(s) to a set of microbeads with different ligand-specificities that have been coded in planar or suspension arrays. The ligand-receptor binding activity is tracked by optical signals generated by means of flow cytometry analysis in the case of suspension arrays, or by image processing devices in the case of planar arrays. In this review paper, we discuss diagnosis of cancer, neurological and infectious diseases by using optically-encoded microbead-based arrays (both multiplexed and single-analyte assays) as a reliable tool for detection and quantification of various analytes.

Multiplex measurement of twelve tumor markers using a GMR multi-biomarker immunoassay biosensor

Tumor markers play an important role in the early diagnosis and therapeutic effect monitoring of tumors. Combined detection of multiple tumor markers is a realistic way of improving the sensitivity and specificity of cancer diagnosis. To achieve this, we studied and designed a giant magneto resistance (GMR) multi-biomarker immunoassay biosensor that can simultaneously detect twelve kinds of tumor markers by integrating a GMR sensor chip, a microfluidic device, a magnetic nano-beads label, and a double antibody sandwich immunoassay method. As a proof of concept, the proposed immunosensor was utilized to detect 12 tumor markers (AFP, CEA, CYFRA21-1, NSE, SCC, PG I, PG II, CA19-9, total PSA, free PSA, free-β-hCG, Tg) and to screen patients with lung cancer, liver cancer, digestive tract cancer, prostatic cancer, etc. The immunosensor showed excellent sensitivity, accuracy, precision and stability. Designed as a POCT device, the immunosensor also allows for portability, able to perform rapid detection wherever necessary. As a multi-analyte assay, it provides significant advantages over single-analyte tests in terms of cost per test, labor and convenience. The system's ability to simultaneously measure the concentration of multiple markers in serum samples with excellent sensitivity and accuracy allows the immunosensor to be used for early tumor diagnosis.

Quantum dot-based lab-on-a-bead system for multiplexed detection of free and total prostate-specific antigens in clinical human serum samples

An immunodiagnostic lab-on-a-bead suspension microarray based on microbeads encoded with quantum dots (QDs) has been developed and preclinically validated for multiplexed quantitative detection of prostate cancer markers in human serum samples. The sensitivity and specificity of the microarray are similar to those of "gold-standard" single-analyte ELISA. Moreover, the array has an improved immunoassay capacity, ensures quantitative detection of multiple cancer biomarkers and may be operational in a considerably wider dynamic range of concentrations. The array is characterized by reduced time and cost of analysis and is compatible with classical flow cytometers. Proof-of-concept preclinical tests ensured simultaneous quantitative determination of free and total prostate-specific antigens in human serum, with clear discrimination between the control and clinical samples. The proposed approach is flexible and paves the way to development of a wide variety of immunodiagnostic assays for multiplexed early diagnosis of various diseases.

FROM THE CLINICAL EDITOR

Early diagnosis of cancer can result in better prognosis for patients. Thus, the use of specific tumor markers is widely employed in clinical practice. Traditional screening methods only employ single markers. The authors here developed a microarray system based on microbeads encoded with quantum dots (QDs), which can be used for multiplexed quantitative detection. The validated results on patient samples should lead to the development of a wider variety of assays for other diseases.

The application of monoclonal antibodies in cancer diagnosis

Cancer becomes the second leading cause of death in the world. An effective strategy for early diagnosis of the disease is key to reduce the mortality and morbidity. Development of effective monoclonal antibody (mAb)-based assays or diagnostic imaging techniques for detection of antigens and small molecules that are released from cancerous cells will enhance modern diagnostic medicine of cancer significantly. Although mAb technology is still under development, recent advances in preparation of recombinant antigen and antibody engineering techniques have dramatically enhanced the applications of this technology in cancer diagnosis. Compared with other methods, mAb-based assays may provide spatial, temporal, accurate and quantitative measurement for diagnosis of the disease. This review summarizes the progress of the mAb-based assays in the field of molecular diagnosis of cancer.

Neutrophil gelatinase-associated lipocalin protein as a biomarker in the diagnosis of breast cancer: A meta-analysis

Neutrophil gelatinase-associated lipocalin (NGAL) has been thought to play an important role in breast cancer tumorigenesis and progression. Various studies have focused on the association between NGAL and breast cancer. The aim of this meta-analysis was to establish the overall accuracy of the NGAL test in the diagnosis of breast cancer. A comprehensive search of the literature was conducted using PubMed, OVID, ScienceDirect and the China National Knowledge Infrastructure (CNKI) databases, and our screening covered all published papers until November 2012. The relevant papers were selected according to stringent inclusion criteria. Essential data were abstracted from the included papers and further analysed by a systematic meta-analysis. The present meta-analysis included four study papers. The summary estimate was 64% (95% CI, 0.59-0.69) for sensitivity and 87% (95% CI, 0.81-0.92) for specificity. The positive likelihood (PLR), negative likelihood (NLR) and diagnostic odds (DOR) ratios were 5.63 (95% CI, 3.63-8.74), 0.32 (95% CI, 0.14-0.71) and 18.02 (95% CI, 9.84-32.98), respectively. The area under the summary ROC curve (AUC) for the diagnosis of breast cancer was 0.9008. Thus, NGAL is a potential biomarker for the diagnosis of breast cancer.

Multiplexed sensing and imaging with colloidal nano- and microparticles

Sensing and imaging with fluorescent, plasmonic, and magnetic colloidal nano- and microparticles have improved during the past decade. In this review, we describe the concepts and applications of how these techniques can be used in the multiplexed mode, that is, sensing of several analytes in parallel or imaging of several labels in parallel.