A microarray-based pathogen chip for simultaneous molecular detection of transfusion-transmitted infectious agents

Multiplex detection and identification of viral, bacterial, and protozoan pathogens in human blood and plasma using an expanded high-density resequencing microarray platform

Introduction: Nucleic acid tests for blood donor screening have improved the safety of the blood supply; however, increasing numbers of emerging pathogen tests are burdensome. Multiplex testing platforms are a potential solution. Methods: The Blood Borne Pathogen Resequencing Microarray Expanded (BBP-RMAv.2) can perform multiplex detection and identification of 80 viruses, bacteria and parasites. This study evaluated pathogen detection in human blood or plasma. Samples spiked with selected pathogens, each with one of 6 viruses, 2 bacteria and 5 protozoans were tested on this platform. The nucleic acids were extracted, amplified using multiplexed sets of primers, and hybridized to a microarray. The reported sequences were aligned to a database to identify the pathogen. To directly compare the microarray to an emerging molecular approach, the amplified nucleic acids were also submitted to nanopore next generation sequencing (NGS). Results: The BBP-RMAv.2 detected viral pathogens at a concentration as low as 100 copies/ml and a range of concentrations from 1,000 to 100,000 copies/ml for all the spiked pathogens. Coded specimens were identified correctly demonstrating the effectiveness of the platform. The nanopore sequencing correctly identified most samples and the results of the two platforms were compared. Discussion: These results indicated that the BBP-RMAv.2 could be employed for multiplex detection with potential for use in blood safety or disease diagnosis. The NGS was nearly as effective at identifying pathogens in blood and performed better than BBP-RMAv.2 at identifying pathogen-negative samples.

A poly(dimethylsiloxane)-based solid-phase microchip platform for dual detection of Pseudorabies virus gD and gE antibodies

Pseudorabies caused by pseudorabies virus (PRV) infection is still a major disease affecting the pig industry; its eradication depends on effective vaccination and antibody (Ab) detection. For a more rapid and accurate PRV detection method that is suitable for clinical application, here, we established a poly(dimethylsiloxane)-based (efficient removal of non-specific binding) solid-phase protein chip platform (blocking ELISA) for dual detection of PRV gD and gE Abs. The purified gD and gE proteins expressed in baculovirus were coated into the highly hydrophobic nanomembrane by an automatic spotter, and the gray values measured by a scanner were used for the S/N (sample/negative) value calculation (gD and gE Abs standard, positive: S/N value ≤0.6; negative: S/N value >0.7; suspicious: 0.6 < S/N ≤ 0.7). The method showed an equal sensitivity in the gD Ab test of immunized pig serum samples compared to the neutralization test and higher sensitivity in the gE Ab test compared to the commercial gE Ab detection kit. In the clinical evaluation, we found an agreement of 100% (122/122) in the gD Ab detection compared to the neutralization test and an agreement of 97.5% (119/122) in the gE Ab detection compared to the commercial PRV gE Ab detection kit. In summary, the protein chip platform for dual detection of PRV gD and gE Abs showed high sensitivity and specificity, which is suitable for PRV immune efficacy evaluation and epidemic monitoring.