Development of a novel rare earth element doped chitosan-graft-poly(hydroxyethyl methacrylate) composite for biomedical applications: synthesis, characterization, drug delivery, and antibacterial properties

The films of chitosan-graft-poly(hydroxyethyl methacrylate) polymer (Ch—g-poly(HEMA)) doped with the rare earth element (REE) lanthanum (La content of 0, 0.2, 0.4, and 0.8 wt.%) were fabricated. The films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), thermogravimetric analysis (TGA), and powder X-ray diffraction (XRD) analysis. The films obtained were loaded with a model drug tetracycline by freezing/thawing method. The cumulative drug release properties of tetracycline were investigated. The release of tetracycline from the polymer matrix was carried out in phosphate-buffered saline (PBS) buffer (pH 7.4) at 37 °C. It was found that the REE-doped composite films had a retarding effect on tetracycline drug release compared to that of the undoped film. All tested composites regardless of the REE dopant content were found to be active against three Gram-positive and three Gram-negative bacterial strains used to assess the antimicrobial properties of the polymer composites. These findings demonstrated that lanthanum and tetracycline have a high affinity for the Ch—g-poly(HEMA) polymer and suggested a synergistic effect in the polymer—lanthanum—tetracycline system. The La³⁺-doped Ch—g-poly(HEMA) composite film can be used as drug carrier system in the biomedical field.