Synthesis, Characterization, and in Vitro Evaluation of Long-Chain Hyperbranched Poly(ethylene glycol) as Drug Carrier

A series of novel long-chain hyperbranched poly(ethylene glycol)s (LHPEGs) with biodegradable connections were designed and synthesized in one pot through proton-transfer polymerization using PEG and commercial glycidyl methacrylate as monomers and potassium hydride as catalyst. The LHPEGs were hydrolyzed at neutral pH resulting in the decrease of molecular weights. In vitro evaluation demonstrated that LHPEGs were biocompatible and displayed negligible hemolytic activity. The efficient cellular uptake of LHPEGs was confirmed by flow cytometry and confocal laser scanning microscopy. Moreover, conjugation of a model hydrophobic anticancer drug methotrexate to LHPEGs inhibited the proliferation of a human cervical carcinoma He la cell line. MTT assay indicated that the conjugated methotrexate dose required for 50% cellular growth inhibition against He la cells was 20 mu g/mL. By combining the advantages of long-chain hyperbranched structure and PEG, LHPEG provides a promising drug carrier for therapeutic fields.