Fabrication And Application Of A Novel Nanostructure-based Hepatitis B Virus Adsorbent

Hepatitis B(HB)is a major problem of liver disease worldwide,which is caused by hepatitis B virus(HBV)infection,including acute and chronic hepatitis,some chronic HB patients even lead to cirrhosis or cancer of the liver.While an effective hepatitis B virus(HBV)has been available since the early 1980 s,chronic HBV infection remains a severe global public health concern.According to the World Health Organization(WHO-2017),around 257 million people are living with hepatitis B virus infection,and these patients are at high risk of developing hepatic decompensation,cirrhosis,and hepatocellular carcinoma(HCC).The infection of HBV is usually diagnosed when HBV surface antigen(HBs Ag)is detected.HBs Ag is not only the most important marker of HBV infection but also a part of the envelope of HBV virion.In clinical practice,clearance of HBs Ag is regarded as the most critical treatment endpoint of chronic hepatitis B(CHB)and associated with an improved clinical outcome,longer survival,and a reduced incidence of cirrhosis and HCC.But spontaneous loss of HBs Ag is a rare event in CHB infection and current treatment options have limited effectiveness and long-term therapy.While existing treatments have focused on drug screening,delivery and targets,there is interest in hemoadsorption system.Extracorporeal blood purification systems including hemofiltration(HF),hemoperfusion(HP)and hemoadsorption(HA)have been explored as alternative approaches for many diseases.They,in common,has the ability to decrease the severity of toxicity and/or duration of poisoning by reducing the concentration of the pathogen associated molecular patterns(PAMPs)in the blood.The key determinant of this kind of system is the target molecule capture efficiency.While HF remove all molecules below a specific size and HP uses activated charcoal or resins as non-specific adsorbents,HA utilizes binding ligands to remove a special type of PAMP.Examples are polymyxin B can bind endotoxin in the treatment of sepsis,protein A can bind Anthrax toxin in the treatment of anthrax.In this study,we compared the classic materials used to prepare adsorbent by measuring the carrier: silica gel,polyvinyl alcohol microsphere,resin,carbide spherical cellulose microspheres and agarose gel 6ff microspheres poisonous to the cells of the cell vitality,and the influence of blood compatibility,and results showed that agarose gel 6 ff microspheres had the best utilization potentiality as carrier for the preparation of novel adsorbent of removing the hepatitis b virus in the blood.For surface-based biomolecular adsorption,a critical challenge is the reduced accessibility of target molecules to ligands arranged on a heterogeneous surface compared to ligand–target binding in homogeneous solution.Much effort has been devoted to control the not only the surface chemistry,conformation,packing density of the ligand molecules,but also the size and geometry of the surface to improve the recognition abilities of such heterogeneous surface ligands.One feasible strategy is introducing DNA nanotechnology as intermediate components.DNA nanotechnology has attracted intense interest because the unparalleled self-recognition properties of DNA offer flexibility and convenience for the ‘bottom-up’ construction of exquisite nanostructures with high controllability and precision.In this study,we compared the synthesis rates of classical DNA nanostructures: DNA tetrahedron,DNA cube,DNA octahedral cage and DNA biconical cone,as well as the binding efficiency with aptamers,and found that DNA tetrahedral nanomaterials can achieve higher aptamer binding efficiency on the basis of ensuring higher synthesis efficiency.In the past few decades,antibodies have drawn a lot of attention as a ligand in HA.Several studies have described that the utilization of immobilized antibodies is a feasible method.The binding specificity of antibody-antigen pairing increases the capture efficiency,reduces the adsorption of natural blood cells and molecules,therefore makes antibodies attractive ligand for HA.Antibodies themselves,however,have many disadvantages.First,the production of antibodies needs high cost and long time.Second,antibodies undergo irreversible denaturation at room temperature or higher.Furthermore,they have high immunogenicity.These problems highlight the need for an alternative to antibodies in order to improve the HA method,and,among different options,the employment of aptamers is an ideal approach.Aptamers are single stranded DNA or RNA oligonucleotides which could be obtained through systematic evolution of ligands by exponential enrichment(SELEX).They have the ability to form well-ordered structures to bind a wide range of specific targets with high specificity and affinity.Compared with traditional antibody ligands,aptamers have higer and more specific affinity,lower cost guaranteed by long shelf life and easier chemical modifications.These outstanding features make them attractive in many applications including nanotechnology,bioanalysis,biosensors and affinity chromatography.A DNA-based aptamer for specific binding to HBs Ag has been reported and used in quantitative detection.In summary,by comparing different carrier materials and intermediate ligands,we bulit the method of preparing a novel hepatitis b adsorbent that takes agarose gel 6FF microsphere as carrier,connects with DNA tetrahedral nanomaterials,and takes adaptor as ligand.On this basis,we also compared the adsorption efficiency of the new adsorbent with the antibody adsorbent and the adsorbent directly connected to the adaptor and proved that the new adsorbent has a higher adsorption efficiency.