Synthesis And Property Research Of New Oxygen Carrier Prepared By New Graft Copolymervesicles

Ideal blood substitutes, also named artificial oxygen carriers or artificial red bloodcells, refer to synthetic solutions with the ability to bind, transport and release oxygenmolecules in the body. To dates biocompatible and biodegradable polymers are commonlyused as the materials to prepare novel artificial oxygen carriers, which is one of the mostcutting-edge research.In this article, six-membered cyclic carbonate,5,5-diazido trimethylene carbonate(DAC) was prepared and used as functional monomer for the ring-openingcopolymerization with LA. The poly(ester-carbonate) product with pendant azido groupsand coupled with alkyne-terminated PEG(A-PEG) via ‘‘click’’ chemistry, resulting inwell-defined biodegradable amphiphilic graft copolymers P(LA-co-DAC)-g-PEG whichcould adjust the hydrophilic surface area of polymer by controlling the number of PEGsegments. Then we investigated structures of polymer by NMR and gel permeationchromatography.The bovine serum albumin solution labeled with fluorescein isothiocyanate(FITC-BSA) was prepared, and used for the experiments of protein adsorption. Then theprotein adsorption of graft copolymers was observed by Inverted fluorescence Microscopeand the adsorption amount of the FITC-BSA was detected by UV. The resaults prove thatthe P(LA-co-DAC)-g-PEG have the more superior capacity of resistance to proteinadsorption than the block copolymers. Cytotoxicity test (MTT) prove that the design ofgraft copolymer vesicle has good biocompatibility.The graft copolymers P(LA-co-DAC)-g-PEG could form nano-aggregates (micelles,vesicles) by the solvent volatilization method. Then the polymersome was used toencapsulate the hemoglobin, which was prove that the hemoglobin were encapsulated inthe polymersome successful by test methods of fluorescence spectroscopy, transmissionelectron microscopy (TEM), dynamic light scattering (DLS) and electrophoresis. Theencapsulation efficiency of protein and polymer-protein ratio of hemoglobin nanoparticleswere assayed by the cyanomethemoglobin method and Inductively Coupled Plasma-MassSpectrometry (ICP-MS). It proved that the hemoglobin encapsulated in polymer vesicles can bind oxygen independently and reversibly by UV.