Preparation And Property Studies Of Betaine-based Polysaccharide Hydrogel

Hydrogel is a type of water-rich polymer with three-dimensional network.Because its structure is similar to the environment in which human tissue cells live,it has been widely used in biomedical and tissue engineering and other fields.However,if anti-adsorption properties of gels such as resistance to proteins are poor,implantation would render gels ineffective and even trigger the immune response of the human body causing undesirable consequences such as tissue necrosis.Based on the development of biological antifouling hydrogels in recent years,we prepared two kinds of functional hydrogels by using sulfonate betaine zwitterionic monomer and natural polysaccharide polymer.The main research contents and conclusions are summarized as follows:⑴We designed and prepared a class of injectable and self-healing hydrogel by using sulfobetaine(SB),chitosan(CS)and sodium alginate(SA)as monomers.First,SB monomer was grafted onto CS chains by Michael addition reaction to increase the water solubility of CS.The modified chitosan reacted with oxidized sodium alginate(OSA)to form the hydrogel through dynamic chemical action.The samples were characterized by FT-IR,XRD and SEM.The hydrogel could be injected through a 0.25 mm inner diameter syringe.After the destruction,the gel incision healed after 4h at room temperature condition without any external force or catalytic action.Anti-protein adsorption,drug release and other tests were investigated through simulating human environment(37℃,PBS buffer solution).Bovine serum albumin(BSA)was chosen as a protein model,the minimum protein adsorption of the SB-CS hydrogel was 22.01μg/cm~2,which decreased by nearly 5-fold compared to the amount of protein adsorbed on chitosan hydrogel.At the same time,the results of the release of tetracycline hydrochloride(TCHC)and rhodamine B were demonstrated that the gel could achieve controlled release of TCHC in response to the pH of the environment.The degradation of the hydrogel in vitro was also investigated.Lysozyme and PBS buffer were used to simulate the human enzyme environment and the natural environment respectively.It was found that the gel could be rapidly degraded in lysozyme,while the degradation time in PBS solution was prolonged.⑵Another class of mechanically enhanced anti-adsorption hydrogels were prepared with SB and agar polysaccharides.The hydrogel was a blend of SB and agar in one-pot and cooled at room temperature to form the first network of physical crosslink of agar,and then a chemically crosslinked network of gel was formed under UV light.The results of FT-IR and SEM showed that the addition of agar could increase the pore structure of single-network poly-sulfonate betaine hydrogel.And the increase of agar content could promote the swelling of hydrogel which speeded up drug release.By using BSA as a protein model,it was found that the gel also had a good anti-protein adsorption property in a simulated human environment,and its anti-protein adsorption property would be enhanced with the increasing of agar content.Mechanical compression tests showed that the toughness and the mechanical strength of the gel could be also enhanced by the increasing agar content.