Recent Patents on Light Based Therapies: Photodynamic Therapy, Photothermal Therapy and Photoimmunotherapy
Emilio J. Sanchez-Barcelo,
Maria D. Mediavilla.
This article reviews the more recent patents in three kinds of therapeutic strategies using the application of
visible light to irradiate photosensible substances (PSs) of different natures. The light-activation of these PSs is directly
responsible for the desired therapeutic effects. This group of light therapies includes photodynamic therapy (PDT), photothermal
therapy (PTT) and photoimmunotherapy (PIT). Therapeutic mechanisms triggered by the activation of the PSs
depend basically (though not exclusively) on the release of reactive oxygen species (ROS) and the activation of immune
responses (PDT and PIT) or the local generation of heat (PTT). The main difference between PIT and PDT is that in PIT,
monoclonal antibodies (MABs) are associated to PSs to improve the selective binding of the PSs to the target tissues. All
these therapeutic strategies offer the possibility of destroying tumor tissue without damaging the surrounding healthy tissue,
which is not achievable with chemotherapy or radiotherapy. PDT is also used as an alternative or adjuvant antimicrobial
therapy together with the traditional antibiotic therapy since these organisms are unlikely to develop resistance to the
ROS induced by PDT. Furthermore, PDT also induces an immune response against bacterial pathogens. The current challenge
in PDT, PIT and PTT is to obtain the highest level of selectivity to act on targeted sick tissues with the minimum effects
on the surrounding healthy tissue. The development of new PSs with high affinity for specific tissues, new PSs-
MABs conjugates to bind to specific kinds of tumors, and new light-sensible nanoparticles with low toxicity, will increase
the clinical utility of these therapies.
Keywords: Cancer therapy, microbial infections, monoclonal antibodies (MABs), nanoparticles, nanovectors, near infrared
radiation (NIR), PDT, photosensitizers, PIT, PTT, reactive oxygen species (ROS), singlet oxygen.
Rights & PermissionsPrintExport