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The Precision Medicine Approach in Oncology
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
To increase throughput for the simultaneous analysis of several proteins, “multiplexing” technologies need to be used, which introduces additional problems. For multiplexing, the same assay conditions for all biomarkers are required (e.g., incubation time, reagents, and dilutions). Also, if a quality check on one single analyte fails, then the complete multiplex panel needs to be re-measured. However, multiplexing of protein assays is becoming commercially successful as evident by the number of companies offering multiplexed panels of various analytes. A key advantage of recent multiplexing methods is the reduced sample volume required (e.g., 150 µL for 100 analytes investigated).
Diagnostic applications of immunology
Published in Gabriel Virella, Medical Immunology, 2019
Ajay Grover, Virginia Litwin, Gabriel Virella
Immunoassays can be adapted to formats that allow multiple simultaneous readings, known as multiplex assays. Two basic formats exist, a plate format and a microsphere format. The bead technology can be compared to an “ELISA-on-a-bead,” the marriage of the ELISA and the flow cytometer. The capture antibody is conjugated to a fluorescent microsphere, and all incubations are performed in solution. The bound antigen is detected with a fluorescent-conjugate detection antibody. The innovation of this method comes from the use of microspheres with varying levels of fluorescence and detection antibodies conjugated to different fluorochromes. This allows for multiplexing so that multiple antigens can be detected from the same sample in the same assay. While it is theoretically possible to measure 100 analytes from a single 50 μL plasma sample, in reality robust assays have been developed for about 5–10 analytes at a time. Challenges of this technology are to find the appropriate buffer conditions for multiple analytes. Furthermore, the assays are not as sensitive or reproducible as some immunoassays for the detection of low levels of antigen. This technology has had great impact in the field of transplantation where it is now routinely used to test for circulating anti-HLA antibodies in the recipients.
Bacterial Sexually Transmitted Diseases
Published in Attila Lorincz, Nucleic Acid Testing for Human Disease, 2016
Julius Schachter, Stephen A. Morse
Technological advances should provide faster, simpler, isothermic NAATs that will be even more suitable for diagnosis and screening. More multiplexing will be seen to allow detection of multiple pathogens with a single test.
The Mini Colon Model: a benchtop multi-bioreactor system to investigate the gut microbiome
Published in Gut Microbes, 2022
Zijie Jin, Andy Ng, Corinne F. Maurice, David Juncker
Several teams have taken another approach, attempting to miniaturize these bioreactors, notably the Mini Bioreactor Arrays (MBRA) and the Mipro systems.15–17 The MBRA can run 24 different experiments in parallel with a working volume of 15 ml and has been used to study the effect of various emulsifiers on gut microbial diversity and composition.18 However, this system still relies on an anaerobic chamber for anoxic conditions and temperature control. In addition, it lacks pH control and relies on expensive multi-channel pumps and multi-point stir plates for fluidic transfer and mixing. In contrast, Mipro operates in batch mode and relies on manual sampling and refilling of bacterial media. Excelling at multiplexing (96 different experiments can run in parallel), this system is more suitable for quick and large-scale initial screening within 24–48 hours instead of time series experiments. However, Mipro is not equipped with a mixing system and similar to the MBRA, it requires an anaerobic chamber for anoxic conditions.17
Colorectal cancer screening and diagnosis: omics-based technologies for development of a non-invasive blood-based method
Published in Expert Review of Anticancer Therapy, 2021
María Gallardo-Gómez, Loretta De Chiara, Paula Álvarez-Chaver, Joaquin Cubiella
Detection and quantification of blood-circulating biomarkers in cfDNA, cfRNA, protein fraction or metabolite is challenging due to their low concentrations, especially in the early stages of cancer. In addition, these low concentrations are masked by the presence of material from healthy cells, which makes their detection even more complicated. Omics approaches contribute to the identification of novel blood-based markers but, unfortunately, many do not show the diagnostic performance sought. This is expected since CRC is a heterogeneous disease, and therefore, a single biomarker will probably not have enough sensitivity and specificity for clinical use. Although single biomarkers may seem simpler, with lower cost, the development of multiplexing methods has encouraged a multi-marker approach. Furthermore, as corroborated by many studies in the last few years, a multi-marker panel is usually more sensitive than a single biomarker [82]. Diagnostic performance and information regarding type of study and technique used for discovery or validation of a selection of potential blood-based biomarkers are shown in Table 2.
Smartphone technology facilitates point-of-care nucleic acid diagnosis: a beginner’s guide
Published in Critical Reviews in Clinical Laboratory Sciences, 2021
Vinoth Kumar Rajendran, Padmavathy Bakthavathsalam, Peter L. Bergquist, Anwar Sunna
In many instances (sepsis, antibiotic resistance), clinical evidence based on a single target is considered inadequate for diagnosis of a disease or for monitoring treatment [147]. Hence it is desirable to screen several analytes simultaneously to enable rapid and reliable diagnosis, and multiplexing has become important for POC testing, adding valuable information for personalized healthcare. The benchtop and handheld devices available require significant improvements to provide the capacity for multiplex sensing [148]. Multiplexing can be achieved through different approaches:The design of reaction chambers with spatially separated wells to allow the performance of simultaneous assays.Regional separation using discrete regions of the detection system.Use of different labels (fluorescent dyes, nanoparticles).