MOL-PCR and xMAP Technology: A Multiplex System for Fast Detection of Food- and Waterborne Viruses

A comprehensive review of Dynamic Chemical Labelling on Luminex xMAP technology: a journey towards Drug-Induced Liver Injury testing

Drug-Induced Liver Injury (DILI) is a grave global adverse event that can result in fatal consequences, causing drug failures, market withdrawals, and regulatory warnings, leading to substantial financial losses. The early detection of DILI remains a significant challenge in global healthcare. Although circulating microRNAs (miRs) show promise as clinical biomarkers for DILI, the current analytical methods for their measurement are insufficient. There is a pressing need for rapid and reliable miR detection methods that eliminate the need for nucleic acid extraction and PCR-based amplification. This review highlights recent advancements achieved by integrating Dynamic Chemical Labelling (DCL) with Luminex xMAP technology. This powerful combination has resulted in groundbreaking bead-based assays that allow (1) the direct, multiplex detection of miRs, and (2) the simultaneous testing of miR and protein biomarkers. This triple capability enables a comprehensive assessment that significantly enhances the detection and analysis of crucial biomarkers, thus improving the understanding and diagnosis of DILI. In conclusion, this review offers valuable insights into the capabilities and potential applications of these groundbreaking assays in DILI research, as well as their potential use in other diagnostic and research domains that require direct or multiplex analysis of miRs or analysis of miRs in combination with proteins.

Rapid, Sensitive, and Selective Quantification of Bacillus cereus Spores Using xMAP Technology

Bacillus cereus is a spore-forming ubiquitous bacterium notable as a food poisoning agent. Detection of B. cereus spores using selective media is laborious and non-specific. Herein, the quantitative detection of B. cereus spores was investigated with commercial antibodies and published aptamer sequences. Several detection reagents were screened for affinity to Bacillus collagen-like protein A (BclA), an abundant exosporium glycoprotein. Sensitivity and selectivity toward B. cereus spores were tested using immunoassays and multi-analyte profiling (xMAP). A recombinant antibody developed in llama against BclA protein showed B. cereus spore selectivity and sensitivity between 10² and 10⁵ spores/mL using xMAP. DNA aptamer sequences demonstrated sensitivity from 10³ to 10⁷ spores/mL and no cross-reaction to B. megaterium and B. subtilis. Selectivity for B. cereus spores was also demonstrated in a mixture of several diverse microorganisms and within a food sample with no compromise of sensitivity. As proof of concept for multiplexed measurement of human pathogens, B. cereus and three other microorganisms, E. coli, P. aeruginosa, and S. cerevisiae, were simultaneously detected using xMAP. These data support the development of a rapid, sensitive, and selective system for quantitation of B. cereus spores and multiplexed monitoring of human pathogens in complex matrices.

MOL-PCR and xMAP technology – a novel approach to the detection of African swine fever virus DNA

African swine fever (ASF) is highly contagious haemorrhagic viral disease of domestic pigs and wild boars. The causative agent can be transmitted by direct contact with infected animals or via a contaminated environment, fomites, feed, meat and products thereof. Soft ticks (genus Ornithodoros) are known reservoirs and transmission vectors of the virus. As the disease causes serious problems in many countries, rapid detection of the agent and early diagnosis could help in prevention of its spread. Therefore, a multiple-analyte profile (xMAP) technology based on multiple oligonucleotide ligation followed by polymerase chain reaction (MOL-PCR) was introduced and verified. A system targeting two independent loci of the virus genome was designed to increase the likelihood of different strains detection and an internal control was employed to verify the correct course of the analysis. The sensitivity was experimentally determined as 10 genomic copies of the virus in one µl of isolated DNA. The system was verified on samples originating from a recent ASF outbreak in the Czech Republic (six spleen) and the Czech market (eight liver and heart tissues) with real-time polymerase chain reaction used as a reference method. The results of both methods were in agreement, even in samples with a low concentration of the virus genome (9.45 × 101 genomic copies/µl of DNA). The system introduced represents an open method allowing the detection and semi-quantification of up to 50 targets/agents in one reaction. It can, therefore, be used for rapid one-step screening and as an effective tool for risk management.