Development Of Novel Biocompatible Hemoadsorbents

Basing on adsorption,hemoperfusion(HP)technology can be used to remove toxic substances from the blood of patients.Activated carbon and resin have been routinely used in hemoperfusion field.However,pristine activated carbon and resin particles present poor blood compatibility which hinders their successful practical applications: firstly,upon contacting with blood,they suffer from non-specific blood protein adsorption which would cover the adsorbents’ surface and significantly reduce their adsorption ability;secondly,pristine adsorbents would result in serious clinical side effects such as particulate micro emboli formation,hemolysis and blood coagulation.Therefore,activated carbon or resin particles should be covered with a polymer coating to improve their blood compatibility.Cellulose nitrate,polyacrylic and polyhydroxyethylmethacrylate,etc.have been commonly used as coating materials of pristine adsorbents.However,current coating materials still could not fully eliminate the negative influence in hemoperfusion applications and therefore the development of novel polymer coatings with better performance is still highly desired.In this work,we have developed zwitterionic poly-carboxybetaine(PCB)hydrogel as the coating material for activated carbon or resin attributed to its excellent biocompatibility.We have investigated the hemocompatibility and the adsorption abilities of new adsorbents for biological molecules in a range of molecular masses.The main contents in this thesis are as follows:1.Two new types of hemoadsorbents were developed using PCB to embed powdered activated carbon(PAC)or resin(PH103).2.The PCB hydrogel encapsulation method could effectively avoid the leakage of activated carbon or resin debris during the adsorption process.The PCB hydrogel coating could significantly improve the hemocompatibility by reducing the degree of hemolysis.3.The use of PCB hydrogel coating improves their hemocompatibility without significantly diminishing their adsorption capacity: PCB-PAC had a strong adsorption capacity to methylene blue and had the ability to isolate and adsorb protein-binding bilirubin;PCB-PH103 was a preferred adsorbent for phenol red,bilirubin and vitamin B12.Moreover,the PCB hydrogel coating could maintain the adsorption performance of the encapsulated adsorbents in a single protein solution or even in 100% fetal bovine serum(FBS),while pristine adsorbents significantly reduced even completely lost their adsorption capacity.These results suggested that zwitterionic hydrogels would be ideal coating materials for adsorbents of blood purification.