Hydrothermal derived protoporphyrin IX nanoparticles for inactivation and imaging of bacteria strains.

Overuse and abuse of antibiotics greatly hasten the development of microbial drug resistance and substantially threat to global public health. Developing alternative methods for combating bacterial infections is urgently required. In this work, a simple hydrothermal approach was employed to prepare the protoporphyrin IX-polyethylenimine nanoparticles (PPIX-PEI NPs) containing abundant amine groups and PPIX moieties. The as-obtained PPIX-PEI NPs exhibit antibacterial properties against both Gram-positive and Gram-negative bacteria. The presence of PPIX in the PPIX-PEI NPs can generate reactive oxygen species (ROS) under 635 nm laser irradiation, which enhance the antibacterial properties of the PPIX-PEI NPs against Gram-positive bacteria. Thus, the PPIX-PEI NPs display a synergistic antibacterial activity against Gram-positive bacteria in the combination of antibacterial photodynamic therapy (PDT). In addition, emission of red fluorescence by the PPIX-PEI NPs can help to differentiate bacteria and observe the bacterial morphologies using a confocal laser scanning microscope (CLSM).

Recent Developments in Controlled Release of Antibiotics.

Traditional use of antibiotics through injection or oral ingestion has many disadvantages, such as detrimental side effects in the host, less effectiveness, high and repeated doses, and development of drug resistance. For prevention and treatment of implant-associated infections, the continuous local delivery of antibiotics is required. Thus, there is a strong demand for the development of drug carrier systems to control the release of antibiotics in a moderate manner over an appropriate timescale. This review summarizes the carrier platforms used for the loading of antibiotics, and highlights their drug release behaviors as well as in vitro and in vivo antibacterial properties.