Establishment of multi-target rapid detection method of upper repiratory susceptible viruses based on digital microfluidic technology

Objective: Provide a digital microfluidic RT-qPCR chip for rapid detection of several upper respiratory diseases. Methods: Several specific primer-probe sets were designed according to the conserved sequences of 2019 novel corona virus(2019-n COV), influenza A virus(Flu A), influenza B virus(Flu B), severe acute respiratory syndrome corona virus(SARS-Co V), Middle East respiratory syndrome corona virus(MERS-Co V), and then packaged into a digital microfluidic chip which allowed simultaneous detection of five upper respiratory tract pathogens with the help of reverse transcription quantitative PCR(RT-q PCR)technology. In the meanwhile, the detection limit, specificity and sensitivity of this digital microfluidic chip were evaluated base on the clinical specimens, plasmids and unrelated pathogens. Results: The established digital microfluidic RT-q PCR chip for 2019-n COV, Flu A, Flu B,SARS-Co V,MERS-Co V had a detection limit of 12 copies/reaction, while the detection limit of the RT-q PCR method without digital microfluidics was 15 copy/reaction;the detection limit of the two methods was basically the same. For nucleic acid samples extracted from clinical samples, the detection results of digital microfluidic RT-q PCR chips were all negative without non-specific amplification. At the same time, the RT-qPCR method and the digital microfluidic RT-qPCR chip method were used to carry out clinical comparative tests of 5 items in 20 clinical samples, total 100 tests. The results showed that the sensitivity of the digital microfluidic RT-q PCR chip reached 94%, the specificity was 100%. SPSS was used to analyze the consistency of the two methods, and the results showed that the two methods had a high degree of consistency(Kappa=0.962, P<0.05). Conclusion: Based on digital microfluidic RT-q PCR chip technology,a multi-target rapid detection method of upper respiratory tract susceptible virus was established, which could provide a new detection method for early clinical identification of respiratory pathogens.

A Digital Microfluidic RT-qPCR Platform for Multiple Detections of Respiratory Pathogens.

The coronavirus disease 2019 pandemic has spread worldwide and caused more than six million deaths globally. Therefore, a timely and accurate diagnosis method is of pivotal importance for controlling the dissemination and expansions. Nucleic acid detection by the reverse transcription-polymerase chain reaction (RT-PCR) method generally requires centralized diagnosis laboratories and skilled operators, significantly restricting its use in rural areas and field settings. The digital microfluidic (DMF) technique provides a better option for simultaneous detections of multiple pathogens with fewer specimens and easy operation. In this study, we developed a novel digital microfluidic RT-qPCR platform for multiple detections of respiratory pathogens. This method can simultaneously detect eleven respiratory pathogens, namely, mycoplasma pneumoniae (MP), chlamydophila pneumoniae (CP), streptococcus pneumoniae (SP), human respiratory syncytial virus A (RSVA), human adenovirus (ADV), human coronavirus (HKU1), human coronavirus 229E (HCoV-229E), human metapneumovirus (HMPV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (FLUA) and influenza B virus (FLUB). The diagnostic performance was evaluated using positive plasmids samples and clinical specimens compared with off-chip individual RT-PCR testing. The results showed that the limit of detections was around 12 to 150 copies per test. The true positive rate, true negative rate, positive predictive value, negative predictive value, and accuracy of DMF on-chip method were 93.33%, 100%, 100%, 99.56%, and 99.85%, respectively, as validated by the off-chip RT-qPCR counterpart. Collectively, this study reported a cost-effective, high sensitivity and specificity on-chip DMF RT-qPCR system for detecting multiple respiratory pathogens, which will greatly contribute to timely and effective clinical management of respiratory infections in medical resource-limited settings.

Structural insights into ORF10 recognition by ZYG11B.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a major threat to human health. As a unique putative protein of SARS-CoV-2, the N-terminus of ORF10 can be recognized by ZYG11B, a substrate receptor of the Cullin 2-RING E3 ubiquitin ligase (CRL2). Here we elucidated recognition mechanism of ORF10 N-terminus by ZYG11B through presenting the crystal structure of ZYG11B bound to ORF10 N-terminal peptide. Our work expands the current understanding of ORF10 interaction with ZYG11B, and may also inspire the development of novel therapies for COVID-19.

Cancer Patient Management Strategy in a Cancer Center of Zhejiang, China During the COVID-19 Pandemic (preprint)

Background: Due to the increased risk of viral infection and the severe shortage of medical resources during the pandemic of COVID-19, most hospitals in the epidemic areas significantly reduced non-emergency admissions and services, if not closed. As a result, it has been difficult to treat cancer patients on time, which adversely affects their prognosis. To address this problem, cancer centers must develop a strategic plan to manage both inpatients and outpatients during the pandemic, provide them with the necessary treatment, and at the same time prevent the spread of the virus among patients, visitors and medical staff. Methods: : Based upon the epidemic situation in Zhejiang Province, China, the number of running non-emergency medical wards in the Zhejiang Cancer Hospital was gradually increased in a controlled manner. All staff of the hospital received COVID-19 preventive training and was provided with three different levels of protection according to the risks of their services. Only patients without a known history of SARS-CoV-2 contact were eligible to schedule an appointment. Body temperature was measured on all patients upon their arrival at the hospital. Chest CT image, blood cell counting and travel/contact history were investigated in patients with fever. Respiratory tract samples, such as sputum and throat swabs, from all patients, including those clinically suspected of SARS-CoV-2 infection, were collected for nucleic acid detection of SARS-CoV-2 before treatment. Results: : A total of 3697 inpatients and 416 outpatients seeking cancer treatment were enrolled from February 1 to April 3, 2020, in compliance with the hospital’s infection-control interventions. The clinicopathological parameters of the patients were summarized herein. 4237 samples from 4101 patients produced negative RNA testing results. Four clinically suspected patients all presented negative RNA test results and were excluded from the SARS-CoV-2 infection through follow-up retesting and monitoring. Seven patients with only N-gene positive results were retested, followed by CT scan and SARS-CoV-2 contact history investigation. All of them were finally diagnosed as non-infected patients. There was one outpatient who was confirmed positive by virus RNA test and then followed up. She might be an asymptomatic laboratory-confirmed case. During the study period, there was no SARS-CoV-2 infection among staff, patients and escorts of patients in the Zhejiang Cancer Hospital. Conclusion: This study suggested our infection-control interventions, including viral nucleic acid test, could be used as a reliable method to screen cancer patients in the area with moderate COVID-19 prevalence. Cancer may not be a high-risk factor of SARS-CoV-2 infection.