[HBsAg quantification: virological significance]

A reusable PMMA/paper hybrid plug-and-play microfluidic device for an ultrasensitive immunoassay with a wide dynamic range

Conventional colorimetric enzyme-linked immunosorbent assay (ELISA) is a time-consuming laboratory assay that is not very sensitive and consumes a large amount of samples. Herein, the development of a reusable, cost-effective, and eco-friendly poly(methyl methacrylate) (PMMA)/paper hybrid plug-and-play (PnP) device for high-sensitivity immunoassay by analyte enrichment and efficient passing-through washing has been reported. The PMMA device has multiple slots where a pre-patterned paper substrate can be inserted. The sample flows back-and-forth through a low-cost, 3D paper substrate within the PMMA channels, thereby enhancing the amount of analyte adsorbed and dramatically increasing the sensitivity while decreasing the assay time. After the enrichment assay, the paper substrate can simply be pulled out of the device, and the results can be qualitatively viewed with the naked eye or scanned through a simple desktop scanner for quantitative analysis. The paper substrate can be replaced with a new substrate so that the device can be reused. The limits of detection (LODs) of 200 pg/mL for immunoglobulin G (IgG) and 270 pg/mL for hepatitis B surface antigen (HBsAg) were obtained. This IgG assay is at least 10 times more sensitive than commercial ELISA kits. In addition, the PnP ELISA exhibited a significant increase in the linear dynamic range from 3 orders of magnitude in a common paper-based device to a wide range of six orders of magnitude in the PnP hybrid device. This reusable PnP device has great potential for the low-cost yet high-sensitivity detection of infectious diseases, cancers, and other important biomolecules.

A paper/polymer hybrid microfluidic microplate for rapid quantitative detection of multiple disease biomarkers

Enzyme linked immunosorbent assay (ELISA) is one of the most widely used laboratory disease diagnosis methods. However, performing ELISA in low-resource settings is limited by long incubation time, large volumes of precious reagents, and well-equipped laboratories. Herein, we developed a simple, miniaturized paper/PMMA (poly(methyl methacrylate)) hybrid microfluidic microplate for low-cost, high throughput, and point-of-care (POC) infectious disease diagnosis. The novel use of porous paper in flow-through microwells facilitates rapid antibody/antigen immobilization and efficient washing, avoiding complicated surface modifications. The top reagent delivery channels can simply transfer reagents to multiple microwells thus avoiding repeated manual pipetting and costly robots. Results of colorimetric ELISA can be observed within an hour by the naked eye. Quantitative analysis was achieved by calculating the brightness of images scanned by an office scanner. Immunoglobulin G (IgG) and Hepatitis B surface Antigen (HBsAg) were quantitatively analyzed with good reliability in human serum samples. Without using any specialized equipment, the limits of detection of 1.6 ng/mL for IgG and 1.3 ng/mL for HBsAg were achieved, which were comparable to commercial ELISA kits using specialized equipment. We envisage that this simple POC hybrid microplate can have broad applications in various bioassays, especially in resource-limited settings.

A paper/polymer hybrid microfluidic microplate for rapid quantitative detection of multiple disease biomarkers

Enzyme linked immunosorbent assay (ELISA) is one of the most widely used laboratory disease diagnosis methods. However, performing ELISA in low-resource settings is limited by long incubation time, large volumes of precious reagents, and well-equipped laboratories. Herein, we developed a simple, miniaturized paper/PMMA (poly(methyl methacrylate)) hybrid microfluidic microplate for low-cost, high throughput, and point-of-care (POC) infectious disease diagnosis. The novel use of porous paper in flow-through microwells facilitates rapid antibody/antigen immobilization and efficient washing, avoiding complicated surface modifications. The top reagent delivery channels can simply transfer reagents to multiple microwells thus avoiding repeated manual pipetting and costly robots. Results of colorimetric ELISA can be observed within an hour by the naked eye. Quantitative analysis was achieved by calculating the brightness of images scanned by an office scanner. Immunoglobulin G (IgG) and Hepatitis B surface Antigen (HBsAg) were quantitatively analyzed with good reliability in human serum samples. Without using any specialized equipment, the limits of detection of 1.6 ng/mL for IgG and 1.3 ng/mL for HBsAg were achieved, which were comparable to commercial ELISA kits using specialized equipment. We envisage that this simple POC hybrid microplate can have broad applications in various bioassays, especially in resource-limited settings.

Detection of Hepatitis B Virus Covalently Closed Circular DNA in the Plasma of Iranian HBeAg-Negative Patients With Chronic Hepatitis B

BACKGROUND

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is a marker of HBV replication in the liver of patients infected with HBV.

OBJECTIVES

This study aimed to investigate the association between the presence of cccDNA in the plasma samples of Iranian treatment-naive patients with chronic hepatitis B infection and HBV viral load and HBsAg levels.

PATIENTS AND METHODS

From April 2012 to May 2015, 106 treatment-naive patients with chronic hepatitis B infection were enrolled in this cross-sectional study. The HBsAg titer was measured by the Roche HBsAg II assay on the Cobas e411 system, and HBV DNA quantitation was performed using the COBAS TaqMan 48 kit. Real-time polymerase chain reaction was performed for the detection of HBV cccDNA.

RESULTS

The mean (SD) age of the patients was 41.1 ± 12.4 years (range, 20 - 62 years). From a total of 106 study participants, 67 (63.2%) were males. The HBV cccDNA was detected in plasma specimens in 19 (17.9%) out of the total 106 patients, and a significant relationship was found between the presence of cccDNA in plasma sample of males (23.9%) and females (7.7%) (P = 0.039). Also, a significant correlation was found between the presence of cccDNA in plasma sample of the patients and HBV viral load level (P < 0.0001) and HBsAg titer (P = 0.0043).

CONCLUSIONS

This study showed that cccDNA can be detected in the plasma specimen of 17.9% of Iranian treatment-naive patients with chronic hepatitis B infection. Therefore, designing prospective studies focusing on the detection of cccDNA in these patients would provide more information.

Evaluation of changes of serum hepatitis B surface antigen from a different perspective

AIM: To investigate the dynamic changes of serum hepatitis B surface antigen (HBsAg) levels apportioned by the same hepatic parenchyma cell volume (HPCV), namely, hepatic cell quantities.

METHODS: Serum HBsAg levels were detected by electrochemiluminescence and serum HBsAg levels apportioned by the same HPCV were figured out according to the theory of sphere geometry. HBsAg levels were compared among different liver inflammation grades, as well as different hepatic fibrosis stages.

RESULTS: In hepatitis B e antigen-negative chronic hepatitis B, serum HBsAg levels in liver histological inflammation grades 1-4 were 3.66 ± 0.40, 3.74 ± 0.35, 3.74 ± 0.26 and 3.71 ± 0.34 log₁₀ COI (cut off index), respectively, and there were no differences before apportion (P = 0.640). Serum HBsAg levels apportioned by the same HPCV were 5.57 ± 0.62, 5.98 ± 0.65, 6.59 ± 0.50 and 6.81 ± 0.84 log₁₀ COI, respectively, and there were significant differences after apportion (P < 0.001). Serum HBsAg levels in hepatic fibrosis stages I-IV were 3.66 ± 0.43, 3.75 ± 0.33, 3.71 ± 0.28 and 3.75 ± 0.26 log₁₀ COI, respectively, and there were no differences before apportion (P = 0.513). Serum HBsAg levels apportioned by the same HPCV were 5.53 ± 0.66, 5.98 ± 0.53, 6.29 ± 0.46 and 7.06 ± 0.48 log₁₀ COI, respectively, and there were significant differences after apportion (P < 0.001).

CONCLUSION: Serum HBsAg levels apportioned by the same HPCV (hepatic cell quantities), rather than serum HBsAg levels, increase with liver inflammation grades and hepatic fibrosis stages.

Dynamic changes in serum HBsAg levels in HBeAg-positive chronic hepatitis B patients with different liver inflammation grades and fibrosis stages

AIM: To investigate the dynamic changes in serum HBsAg levels in HBeAg-positive chronic hepatitis B patients with different liver histological inflammation grades and hepatic fibrosis stages.

METHODS: Serum HBsAg levels in HBeAg-positive chronic hepatitis B patients were detected by electrochemiluminescence. Serum HBsAg levels were compared between patients with grades 1, 2, 3 and 4 liver histological inflammation, and between those with stages 1, 2, 3 and 4 hepatic fibrosis.

RESULTS: Serum HBsAg levels in patients with grades 1, 2, 3 and 4 liver histological inflammation were 2998 COI/mL ± 2515 COI/mL, 4064 COI/mL ± 2468 COI/mL, 5513 COI/mL ± 2390 COI/mL and 5736 COI/mL ± 1838 COI/mL, respectively; while the values in patients with stages 1, 2, 3 and 4 hepatic fibrosis were 3159 COI/mL ± 2577 COI/mL, 4075 COI/mL ± 2149 COI/mL, 5670 COI/mL ± 2189 COI/mL and 5976 COI/mL ± 2128 COI/mL, respectively. There were significant differences in serum HBsAg levels between different liver inflammation grades, as well as between different hepatic fibrosis stages (F = 9.986, P < 0.000; F = 13.955, P < 0.000).

CONCLUSION: Serum HBsAg levels increase dynamically along with the damage of hepatic tissues in patients with HBeAg-positive chronic hepatitis B.