Prof. Rachel Lubart, of the Departments of Chemistry and Physics, is focused on visible light- tissue interaction. In order to interact with the living cell, light has to be absorbed by intracellular chromophores.
Lubart has suggested that endogenous porphyrins, mitochondrial cytochromes flavoproteins, and the NADPH-oxidase system, can be targets of light. Intracellular chromophores are photosensitizers and generate reactive oxygen species (ROS) following irradiation. Using the EPR spin trapping technique, Lubart has demonstrated that various ROS are formed in many cell cultures, including skin, muscle, sperm, bacteria, and fungi, following irradiation with light sources in the visible and near Infra Red ranges.
While light-induced ROS in small quantities stimulate cell activities, high concentrations are lethal to the cell, and are thus used for killing bacteria. While lasers are versatile tools in the laboratory, the specific characteristics of laser light, such as coherency and polarization, have been proven by Lubart to be irrelevant for light-tissue interaction.
Lubart has developed a new light device which emits a broad band of wavelengths at targeted intensities, and is thus capable of cell activation through small amounts of ROS formation and changes in calcium transport.
Her device was found to mimic laser light functions in the area of photo-bio-stimulation, such as acceleration of cell proliferation for wound healing and for enhancement of the fertilization rate of damaged sperm cells.
Lubart’s light device is CE-approved and is now being used for severe wound healing, particularly for diabetics.
Lubart also uses high intensity visible light, without the addition of exogenous photosensitizers as used in photodynamic therapy (PDT), for bacteria and fungi killing.
Recently she proved the lethal effect of high intensity visible light on pathogens like S. marcescens, P. aeruginosa 1316, S. aureus 195 and E. coli 1313, and C. albicans, which are prevalent in wound infections.
Lubart and her team have also loaded nano-particles as a source of oxy radicals into various pathogens for enhancing the lethal light effect. The combination of metal oxides, nano-particles and visible light is now being examined for treating Acne vulgaris.
Metal oxide nanoparticles also have toxic effects on host tissues through the production of ROS. In order to reduce this toxicity, Lubart and her team suggest depositing them on transparent textiles, e.g. bandages, which will be loaded on the acne wounds before visible light irradiation.