Synthesis And Properties Of Functional Betaine-based Hydrogel By RAFT Polymerization

A series of the poly(N-isopropylacrylamide)-g-poly(sulfobetaine methacrylate)(PNIPAM-g-PSBMA) hydrogel, poly(hydroxyethyl methacrylate)-g-poly(sulfobetaine methacrylate)(PHEMA-g-PSBMA) hydrogels and poly(N-isopropylacrylamide)-g-polycarboxybetaineester (PNIPAM-g-PCBMAE) hydrogels were prepared by reversible addition-fragmentationchain transfer polymerization using sulfobetaine methacrylate(SBMA), carboxybetaineester(CBMAE), N-isopropylacrylamide(NIPAM) and hydroxyethyl methacrylate(HEMA) asmonomers. The structures and properties of these hydrogel were studied as follow.(1) PNIPAM-g-PSBMA hydrogel was firstly characterized by FTIR and SEM. Comparedto the poly(N-isopropyl-acrylamide)-co-poly(sulfobetaine methacrylate)(PNIPAM-co-PSBMA) hydrogel by conventional radical polymerization, PNIPAM-g-PSBMA hydrogelexhibited much faster shrinking rate in response to temperature changes. The releasebehaviors of tetracycline hydrochloride (TCHC) of the hydrogels indicated the TCHC releasefrom PNIPAM-g-PSBMA hydrogel could be prolonged to48h at37°C. Bovine serumalbumin (BSA) was chosen as the model protein to examine the lowfouling property of thePNIPAM-g-PSBMA hydrogel. The BSA adsorption data showed that PNIPAM-g-PSBMAhydrogel was be effectively resistant to protein adsorption (protein adsorption≤3.5μg/cm2).(2) A series of PNIPAM-g-PSBMA hydrogels were firstly characterized by FTIR andSEM. The swelling ratios, mechanical properties and drug release kinetics of these hydrogelswere investigated at37°C. It was found that the mechanical strengths and drug releasebehaviors were significantly affected by the feed ratios. The hydrophilic TCHC release resultssuggested that PHEMA-g-PSBMA hydrogels could sustain drug release for a longer periodwith increasing the HEMA content, and the TCHC release rates could be adjusted by varyingthe HEMA amount in the gel networks. The bovine serum albumin (BSA) adsorption datashowed that the PHEMA-g-PSBMA hydrogel with18.2weight percentages of SBMAexhibited good protein resistant property at37°C.(3) A series of PNIPAM-g-PSBMA hydrogels were firstly characterized by FTIR. Thenthe antibacterial activities of PNIPAM-g-PCBMAE hydrogels against Staphylococcus aureus(S. aureus) were firstly investigated. It was found that these hydrogels exhibited excellentantimicrobial activities against S. aureus. Non-ionic TCHC and anionic sodium salicylate (SA)were selected to evaluate the loading capacities and release kinetics of the hydrogels at37℃.It was observed that the loading efficiencies of TCHC in the PNIPAM-g-PCBMAE hydrogelswere approximately twice higher than those of SA. However, the cumulative release amount of TCHC was lower than that of SA from the corresponding cationic hydrogel. In addition, thePNIPAM-g-PCBMAE hydrogels exhibited the accelerated release rates of both TCHC and SAwith increasing the content of CBMAE.