Microfluidic Chip And Graphene Oxide For Detection And Prevention Of Hepatitis B

Hepatitis B virus (HBV) is a major cause of acute and chronic hepatitis, liver cirrhosis(LC) and hepatocellular carcinoma (HCC). HBV infection is a highly endemic disease inChina. There are approximately93million HBV carriers, and among them20million arepatients with chronic hepatitis B. Hepatitis B virus (HBV) can be classified into tengenotypes (A-J), and genotype B and C are dominant in China. HBV genotypes mayinfluence hepatitis B e antigen (HBeAg) seroconversion rate, mutational pattern in the basalcore promoter (BCP) and precore (PC) regions, the course of liver disease and antiviraltreatment effect. Genotyping may be helpful for clinical diagnosis and effective therapeuticdrug selection.In order to overcome shortcomings of reported methods, such as time-consumpion, lowsensitivity and inferior specificity, we combined giant magnetoresistance (GMR) sensors,loop-mediated isothermal amplification (LAMP), magnetic nanoclusters (MNCs) and line-probe assay (LiPA) to fabricate a microfluidic biochip to distinguish Chinese dominant HBVgenotype B and C. This detection method integrating multiple functions such as samplesmixing, nucleic acid amplification and signal acquisition, has several advantages of shorterdetection time, preferable antijamming ability, higher sensitivity and specificity.Firstly, a quick genotyping method of human hepatitis B virus was established by aspecially designed giant magnetoresistive (GMR) biochip combined with magneticnanoclusters (MNCs), PCR and line probe assay. Magnetic nanoclusters with a.c.172nm were prepared and modified with Streptavidin, and the resultant Streptavidin modifiedmagnetic nanoclusters were used for capturing biotin-labeled hybrid products on the surfaceof detection sensor. The detection sensitivity is200IU·mL-1target HBV DNA molecules.The microfluidic biochip for HBV genotyping subsequently was improved by integratingLAMP into the microfluidic chip and separating GMR sensors as a reusable detector. Thelimit of detection attained10copies·mL-1target HBV DNA molecules within one hour.Lastly, a bionic microfluidic mixer was designed for fast and efficient mixing nucleic acidsamples and reagents before nucleic acid amplification. The mixer consists of a number ofalternate connected straight microchannels and circular chambers.In order to investigate the possibility of graphene oxide as immune adjuvant, theimmunotoxicity of graphene oxide and the effect of PVP-coating were evaluated in vitro.The experimental results showed that PVP-coating GO possesses good immunologicalbiocompatibility and immunoenhancement effects in vitro, and is likely to be an availablecandidate of immunoadjuvant in the future.