Development of a multi-recombinase polymerase amplification assay for rapid identification of COVID-19, influenza A and B.

The coronavirus disease 2019 (COVID-19) pandemic caused extensive loss of life worldwide. Further, the COVID-19 and influenza mix-infection had caused great distress to the diagnosis of the disease. To control illness progression and limit viral spread within the population, a real-time reverse-transcription PCR (RT-PCR) assay for early diagnosis of COVID-19 was developed, but detection was time-consuming (4-6 h). To improve the diagnosis of COVID-19 and influenza, we herein developed a recombinase polymerase amplification (RPA) method for simple and rapid amplification of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19 and Influenza A (H1N1, H3N2) and B (influenza B). Genes encoding the matrix protein (M) for H1N1, and the hemagglutinin (HA) for H3N2, and the polymerase A (PA) for Influenza B, and the nucleocapsid protein (N), the RNA-dependent-RNA polymerase (RdRP) in the open reading frame 1ab (ORF1ab) region, and the envelope protein (E) for SARS-CoV-2 were selected, and specific primers were designed. We validated our method using SARS-CoV-2, H1N1, H3N2 and influenza B plasmid standards and RNA samples extracted from COVID-19 and Influenza A/B (RT-PCR-verified) positive patients. The method could detect SARS-CoV-2 plasmid standard DNA quantitatively between 102 and 105 copies/ml with a log linearity of 0.99 in 22 min. And this method also be very effective in simultaneous detection of H1N1, H3N2 and influenza B. Clinical validation of 100 cases revealed a sensitivity of 100% for differentiating COVID-19 patients from healthy controls when the specificity was set at 90%. These results demonstrate that this nucleic acid testing method is advantageous compared with traditional PCR and other isothermal nucleic acid amplification methods in terms of time and portability. This method could potentially be used for detection of SARS-CoV-2, H1N1, H3N2 and influenza B, and adapted for point-of-care (POC) detection of a broad range of infectious pathogens in resource-limited settings.

Bioinspired Healable Mechanochromic Function from Fluorescent Polyurethane Composite Film.

Camouflage and wound healing are two vital functions for cephalopods to survive from dangerous ocean risks. Inspired by these dual functions, herein, we report a new type of healable mechanochromic (HMC) material. The bifunctional HMC material consists of two tightly bonded layers. One layer is composed of polyvinyl alcohol (PVA) and titanium dioxide (TiO2) for shielding. Another layer contains supramolecular hydrogen bonding polymers and fluorochromes for healing. The as-synthesized HMC material exhibits a tunable and reversible mechanochromic function due to the strain-induced surface structure of composite film. The mechanochromic function can be further restored after damage because of the incorporated healable polyurethane. The healing efficiency of the damaged HMC materials can even reach 98 % at 60 °C for 6 h. The bioinspired HMC material is expected to have potential applications in the information encryption and flexible displays.

Development of a biomimetic liver tumor-on-a-chip model based on decellularized liver matrix for toxicity testing.

Cancer poses a great health threat to both developed and developing countries, and anti-cancer drugs are of important interest for improved clinical outcomes. Although tumor-on-a-chip technologies offer a feasible approach to screening drug toxicity, their capability to mimic the native tumor microenvironment (TME) is still limited. For better mimicry of the TME, we developed a biomimetic three-dimensional (3D) liver tumor-on-a-chip with the integration of essential components derived from decellularized liver matrix (DLM) with gelatin methacryloyl (GelMA) in a microfluidics-based 3D dynamic cell culture system. The biomimetic liver tumor-on-a-chip based on the integration of DLM components with GelMA, as opposed to GelMA only, had an increased capability to maintain cell viability and to enhance hepatocyte functions under flow conditions. The improved performance of the DLM-GelMA-based tumor-on-a-chip may be attributed to the provision of biochemical factors (e.g., growth factors), the preservation of scaffold proteins, and the reestablishment of biophysical cues (e.g., stiffness and shear stress) for better recapitulation of the 3D liver TME. Furthermore, this DLM-GelMA-based tumor-on-a-chip exhibited linear dose-dependent drug responses to the toxicity of acetaminophen and sorafenib. Taken together, our study demonstrates that the DLM-GelMA-based biomimetic liver tumor-on-a-chip better mimics the in vivo TME and holds great promise for a breadth of pathological and pharmacological studies.

An Integrated Double-Filtration Microfluidic Device for Detection of Extracellular Vesicles from Urine for Bladder Cancer Diagnosis.

Extracellular vesicles (EVs) are present in a variety of bodily fluids and they play an important role in cellular communications and signal transduction mechanisms. Studies have shown that the number of EVs and EV-associated biomarkers (i.e., proteins, nucleic acids and lipids) can be used to aid clinical diagnosis. Although ultracentrifugation is commonly used for EV isolation, it is not practical for clinical settings. Here, we developed an integrated double-filtration device that isolated and enriched EVs from urine, and subsequently detected/quantified EVs from urine via microchip ELISA. Results showed that the concentration of EVs was significantly elevated compared to healthy controls. Receiver operating characteristic analysis demonstrated that this integrated EV quantification device had a sensitivity of 81.3% at a specificity of 90% (16 bladder cancer patients and eight healthy controls). Thus, this integrated device shows great potential to supplement urine cytology for diagnosis of bladder cancer in point-of-care (POC) settings.

An integrated double-filtration microfluidic device for isolation, enrichment and quantification of urinary extracellular vesicles for detection of bladder cancer.

Extracellular vesicles (EVs), including exosomes and microvesicles, are present in a variety of bodily fluids, and the concentration of these sub-cellular vesicles and their associated biomarkers (proteins, nucleic acids, and lipids) can be used to aid clinical diagnosis. Although ultracentrifugation is commonly used for isolation of EVs, it is highly time-consuming, labor-intensive and instrument-dependent for both research laboratories and clinical settings. Here, we developed an integrated double-filtration microfluidic device that isolated and enriched EVs with a size range of 30-200 nm from urine, and subsequently quantified the EVs via a microchip ELISA. Our results showed that the concentration of urinary EVs was significantly elevated in bladder cancer patients (n = 16) compared to healthy controls (n = 8). Receiver operating characteristic (ROC) analysis demonstrated that this integrated EV double-filtration device had a sensitivity of 81.3% at a specificity of 90% (16 bladder cancer patients and 8 healthy controls). Thus, this integrated device has great potential to be used in conjunction with urine cytology and cystoscopy to improve clinical diagnosis of bladder cancer in clinics and at point-of-care (POC) settings.

Epidemiological characteristics of malaria prevalence in Danyang City from 2004 to 2015 / 中国血吸虫病防治杂志

Objective To analyze the epidemiological characteristics of malaria prevalence in Danyang City from 2004 to 2015,so as to provide the evidence for formulating the strategy of prevention and control of malaria. Methods The data of ma-laria serum tests,the reported malaria cases from the Internet Reporting System,and the epidemiological case survey from 2004 to 2015 as well as the mosquito monitoring data from 2008 to 2015 were collected and analyzed. Results From 2004 to 2015, 58 malaria cases were reported in Danyang City,with an average annual incidence rate of 0.6/105. Among the cases reported, vivax malaria accounted for 65.52％(38/58),falciparum malaria accounted for 5.17％(3/58),oval malaria accounted for 1.72％(1/58),and unclassified subtype accounted for 27.59％(16/58). The local infection cases accounted for 31.03％(18/58),and the imported cases accounted for 68.97％(40/58). There were no local infections since 2011. Anopheles sinensis,the only malaria vector in Danyang City,was still prevalent,but its density was low. Conclusion Imported malaria poses a serious threat to the malaria elimination achievements in Danyang City,and the surveillance and disposal of imported malaria need to be strengthened.

Advances in addressing technical challenges of point-of-care diagnostics in resource-limited settings.

The striking prevalence of HIV, TB and malaria, as well as outbreaks of emerging infectious diseases, such as influenza A (H7N9), Ebola and MERS, poses great challenges for patient care in resource-limited settings (RLS). However, advanced diagnostic technologies cannot be implemented in RLS largely due to economic constraints. Simple and inexpensive point-of-care (POC) diagnostics, which rely less on environmental context and operator training, have thus been extensively studied to achieve early diagnosis and treatment monitoring in non-laboratory settings. Despite great input from material science, biomedical engineering and nanotechnology for developing POC diagnostics, significant technical challenges are yet to be overcome. Summarized here are the technical challenges associated with POC diagnostics from a RLS perspective and the latest advances in addressing these challenges are reviewed.