Amino poly(glycerol methacrylate)s (PGOHMAs) were synthesized from linear and 8-arm poly(glycidyl methacrylate)s (PGMAs) via ring opening reactions with methylethylamine (MEA), diethylamine, and dipropylamine, respectively, which were further modified by quaternization reaction using methyl iodide to obtain quaternized PGMAs (QPGMAs for short). The products were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, and thermogravimetric analysis. The amination percentage of amino PGOHMAs and the degree of quaternization of QPGMAs were calculated by elemental analysis and X-ray photoelectron spectroscopy, respectively. According to the solubility test results, 8-arm PGOHMA modified with MEA (S8-MEA) is the only water-soluble derivative of amino PGOHMAs and was employed as a positive control for the comparison with QPGMAs. Antimicrobial studies on these PGMA derivatives were carried out by testing the minimum inhibitory concentration and the bacteria inhibitive rate against Escherichia coli and Staphylococcus aureus. The results indicated that QPGMAs possessed higher antimicrobial activity than S8-MEA and exhibited increased antimicrobial activity against both bacteria with an increased degree of quaternization in weak basic conditions. Moreover, the chemical structure of PGMA derivatives and pH value of the assay conditions were found to affect the antimicrobial activity.

A series of cationic polymers based on b-cyclodextrin (b-CD)-conjugated amino poly(glycerol methacrylate)s (PGOHMAs) was synthesized for potential insulin delivery by forming polyelectrolyte complexes (PECs). Both linear and star-shaped poly(glycidyl methacrylate)s were functionalized with mono(6-(diethylenetriamine)-6-deoxy)-b-CD and diethylenetriamine to obtain CD-DETA-PGOHMAs and DETA-PGOHMAs, respectively. The resulting polymers were characterized by 1 H NMR, FT-IR, elemental analysis, and TGA, and then used to prepare PECs with insulin. The association efficiency and loading capacity of CD-DETA-PGOHMAs were higher than those of DETA-PGOHMAs. The release of insulin depended on the introduction of b-CDs, the backbone architecture of the polymers, as well as the pH.The competitive binding release study indicted that insulin could be released rapidly when 1-aminoadamantane hydrochloride (ADA) was used as a competitive binding guest molecule. The in vitro cytotoxicity study revealed that CD-series polymers have much lower toxicity than the D-series. The CD-DETA-PGOHMA/insulin complexes, with lower cytotoxicity and proper release rate, showed great potential for insulin controlled release.

The oil-based formulation fabricated from biodegradable PEG-b-PLA-CD copolymers with high drug loading showed great potential for protein delivery.