Microbial infection is a severe concern, requiring the use of significant amounts of antimicrobials/biocides, not only in the hospital setting, but also in other environments. The increasing use of antimicrobial drugs and the rapid adaptability of microorganisms to these agents, have contributed to a sharp increase of antimicrobial resistance. It is obvious that the development of new strategies to combat planktonic and biofilm-embedded microorganisms is required. Photodynamic inactivation (PDI) is being recognized as an effective method to inactivate a broad spectrum of microorganisms, including those resistant to conventional antimicrobials. In the last few years, the development and biological assessment of new photosensitizers for PDI were accompanied by their immobilization in different supports having in mind the extension of the photodynamic principle to new applications, such as the disinfection of blood, water, and surfaces. In this review, we intended to cover a significant amount of recent work considering a diversity of photosensitizers and supports to achieve an effective photoinactivation. Special attention is devoted to the chemistry behind the preparation of the photomaterials by recurring to extensive examples, illustrating the design strategies. Additionally, we highlighted the biological challenges of each formulation expecting that the compiled information could motivate the development of other effective photoactive materials.

Photodynamic therapy (PDT) is a modality of cancer treatment in which tumor cells are destroyed by reactive oxygen species (ROS) produced by photosensitizers following its activation with visible or near infrared light. The PDT success is dependent on different factors namely on the efficiency of the photosensitizer deliver and targeting ability. In this review a special attention will be given to the role of some drug delivery systems to improve the efficiency of tetrapyrrolic photosensitizers to this type of treatment.

Cancer is the second leading cause of death worldwide; therefore, there is an urgent need to find safe and effective therapies. Triple-negative breast cancer (TNBC) is diagnosed in ca. 15–20% of BC and is extremely aggressive resulting in reduced survival rate, which is mainly due to the low therapeutic efficacy of available treatments. Photodynamic therapy (PDT) is an interesting therapeutic approach in the treatment of cancer; the photosensitizers with good absorption in the therapeutic window, combined with their specific targeting of cancer cells, have received particular interest. This review aims to revisit the latest developments on chlorin-based photoactive molecules for targeted therapy in TNBC. Photodynamic therapy, alone or combined with other therapies (such as chemotherapy or photothermal therapy), has potential to be a safe and a promising approach against TNBC.

New porphyrin/4-oxoquinoline conjugates were synthesized from the Heck coupling reaction of a β-brominated porphyrin with 1-allyl-4-oxoquinoline derivatives, followed by demetallation and deprotection affording the promising photosensitizers 9a–e. Singlet oxygen studies have demonstrated that all the porphyrin/4-oxoquinoline conjugates 9a–e were capable of producing cytotoxic species and found to be excellent photosensitizing agents in the inactivation of S. aureus by the antimicrobial photodynamic therapy (aPDT) protocol.