Background and ObjectiveRapid on-site testing with low sample volume and point-of-care diagnostics are very useful for preventive measures against hepatitis B virus. Therefore, the aim of this study is to develop a rapid, accurate, and cost-effective lateral ow biosensor for convenient HBV nucleic acid detection at the point-of-care.
MethodsClinical serum samples with HBV-positive real-time PCR assays were used for the experiments. Spin column nucleic acid puri cation and serum heat treatment were used for sample preparation. A 250 bp fragment of the HBV polymerase gene was ampli ed with 3 pairs of speci c biotin-and FITC-labeled LAMP primers. Different incubation temperatures (64-68° C) and times (30 min, 45 min, and 1 h) were explored for optimal LAMP assay, and results were assessed by uorometric analysis, white turbidity, and lateral ow assay. Ready-to-use Milenia HybriDetect1 strips were used to visualize the LAMP amplicons.Subsequently, 10-fold serial dilutions of a secondary standard containing 10 8 IU/ml viral load were used to evaluate lateral ow biosensor performance.
ResultsThe LAMP reaction was optimized at 67 •C, and appreciable turbidity was achieved after 30 minutes of incubation. Templates from 10 8 IU/ml to 10 1 IU/ml exhibited distinct test bands when spin column approach was used as the puri cation method. However, the minimum viral load detectable by lateral ow was 10 3 IU/ml when serum samples were treated with heat and the supernatant was directly used for LAMP. The result shows that the developed LAMP-LF assay was able to detect a viral load of 10 1 IU/ml only in 66.6% of cases.
ConclusionThe LAMP-LF assay is a potential solution for HBV testing in resource-limited settings. Overall, our study demonstrated that the integration of LAMP -LF assay can be a plausible approach for point-of-care application with high sensitivity and accuracy. However, direct ampli cation without DNA puri cation is excluded and may lead to poor performance of the approach.