Infection of hepatitis B virus in extrahepatic endothelial tissues mediated by endothelial progenitor cells

BACKGROUND: Hepatitis B virus (HBV) replication has been reported to be involved in many extrahepatic viral disorders; however, the mechanism by which HBV is trans-infected into extrahepatic tissues such as HBV associated myocarditis remains largely unknown. RESULTS: In this study, we showed that human cord blood endothelial progenitor cells (EPCs), but not human umbilical vein endothelial cells (HUVECs) could be effectively infected by uptake of HBV in vitro. Exposure of EPCs with HBV resulted in HBV DNA and viral particles were detected in EPCs at day 3 after HBV challenge, which were peaked around day 7 and declined in 3 weeks. Consistently, HBV envelope surface and core antigens were first detected in EPCs at day 3 after virus challenge and were retained to be detectable for 3 weeks. In contrast, HBV covalently closed circular DNA was not detected in EPCs at any time after virus challenge. Intravenous transplantation of HBV-treated EPCs into myocardial infarction and acute renal ischemia mouse model resulted in incorporation of HBV into injured heart, lung, and renal capillary endothelial tissues. CONCLUSION: These results strongly support that EPCs serve as virus carrier mediating HBV trans-infection into the injured endothelial tissues. The findings might provide a novel mechanism for HBV-associated myocarditis and other HBV-related extrahepatic diseases as well

A New Hematocrit Measurement Method Using a Chemiluminescence Biosensor and Its Application in a Chemiluminescence Immunoassay Platform for Myocardial Markers Detection with Whole Blood Samples

The accuracy and precision of analyte concentrations measured in whole blood by chemiluminescence immunoassay (CLIA) have been significantly affected by erythrocytes, which leads to poor application of whole blood CLIA in clinical practice. In this work, a chemiluminescence biosensing optical platform for blood hematocrit (HCT) analysis using MAGICL 6000 (Getein Biotechnology, Nanjing, China) was designed, implemented, and fully characterized. The developed method was successfully applied to determine various HCT levels of human blood from 0% to 65%, with a correlation coefficient of 0.9885 compared with the conventional method (Sysmex XE 5000, Kobe, Japan). A mathematical model was developed to quantitatively evaluate the impact of HCT on the results of two sample types (whole blood vs. plasma). Combining the established HCT method and mathematical model with CLIA on MAGICL 6000, the precision was significantly improved by almost 20%. Comparison studies using whole blood samples and corresponding plasma samples showed that the square of the correlation coefficients of troponin I (cTnI), myoglobin (MYO), creatine kinase MB (CK-MB), and N-terminal pro-hormone brain natriuretic peptide (NT-proBNP) were increased to 0.9992, 0.9997, 0.9996, and 0.9994, respectively, showing a great potential for clinical application

Transpiration-Inspired Fabrication of Opal Capillary with Multiple Heterostructures for Multiplex Aptamer-Based Fluorescent Assays

In this work we report a method for the fabrication of opal capillary with multiple heterostructures for aptamer-based assays. The method is inspired by plant transpiration. During the fabrication, monodisperse SiO₂ nanoparticles (NPs) self-assemble in a glass capillary, with the solvent gradually evaporating from the top end of the capillary. By a simple change of the colloid solution that wicks through the capillary, multiple heterostructures can be easily prepared inside the capillary. On the surface of the SiO₂ NPs, polydopamine is coated for immobilization of aminomethyl-modified aptamers. The aptamers are used for fluorescent detection of adenosine triphosphate (ATP) and thrombin. Owing to fluorescence enhancement effect of the photonic heterstructures, the fluorescent signal for detection is amplified up to 40-fold. The limit of detection is 32 μM for ATP and 8.1 nM for thrombin. Therefore, we believe this method is promising for the fabrication of analytical capillary devices for point-of-care testing

Selection of HBsAg-Specific DNA Aptamers Based on Carboxylated Magnetic Nanoparticles and Their Application in the Rapid and Simple Detection of Hepatitis B Virus Infection

Aptamers are short single-stranded DNA or RNA oligonucleotides and can be selected from synthetic combinatorial libraries in vitro. They have a high binding affinity and specificity for their targets. Agarose gels, nitrocellulose membranes, and adsorptive microplates are often used as carriers to immobilize targets in the SELEX (systematic evolution of ligands by exponential enrichment) process, but the subsequent separation step is tedious and time-consuming. Therefore, we used magnetic nanoparticles (MNPs) as carriers to immobilize the target, hepatitis B surface antigen (HBsAg), which is convenient for fast magnetic separation. In this study, we first selected DNA aptamers against HBsAg by immobilizing HBsAg on the surface of carboxylated MNPs. The ssDNA library of each selection round was prepared by asymmetric PCR amplification for the next selection round. To obtain aptamer sequences, the final selected products were purified by gel electrophoresis, then cloned, and sequenced. DNA aptamers that specifically bind to HBsAg were successfully obtained after 13 selection rounds. The selected aptamers were used to construct a chemiluminescence aptasensor based on magnetic separation and immunoassay to detect HBsAg from pure protein or actual serum samples. There was a linear relationship between HBsAg concentration and chemiluminescent intensity in the range of 1–200 ng/mL. The aptasensor worked well even in the presence of interfering substances and was highly specific in the detection of HBsAg in serum samples, with a detection limit 0.1 ng/mL lower than the 0.5 ng/mL limit of an ELISA in use at the hospital. This aptasensor can contribute to better detection of hepatitis B virus infection