Well-defined hydroxyapatite–polycation nanohybrids via surface-initiated atom transfer radical polymerization for biomedical applications

Abstract

The ability to manipulate and control the surface properties of hydroxyapatite (HA) nanoparticles is of crucial importance for the design of HA-based carriers of therapeutic agents. In this work, surface-initiated atom transfer radical polymerization (ATRP) of (2-dimethyl amino)ethyl methacrylate (DMAEMA) is first employed to tailor the functionality of HA surfaces in a well-controlled manner and to produce a series of new cationic hybrids (termed as HA-PDM). The HA parts of HA-PDM were coated by different lengths of PDMAEMA chains. The HA-PDM exhibited a good ability to condense plasmid DNA (pDNA) with suitable particle size and a zeta potential for gene transfection. Most importantly, in comparison with PDMAEMA homopolymers, the HA-PDM displayed considerably enhanced buffering capacity, and exhibited much higher gene transfection efficiencies in different cell lines, including osteoblast MC3T3 and osteosarcoma MG63 cells. In addition, the HA-PDM/pDNA complexes also could largely enhance the differentiation of preosteoblast cells. Such well-defined HA-PDM nanohybrids possess great potential applications as new drug-delivery vectors in bone tissue engineering.