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Liposomes are phospholipid-based self-assembled nanoparticles. Various components can be solubilized in the lipid bilayer, encapsulated in the aqueous core or attached to the surface, making liposomes attractive platforms for multimodality functionalization. Here we describe theranostic liposomes delivering a magnetic resonance contrast agent (lipid derivative of gadopentetic acid) and a hydrophobic photosensitizer (zinc phthalocyanine, ZnPc) for photodynamic therapy of cancer. For the first time, this theranostic system was prepared by the microfluidic method. Analogous formulations were produced by thin lipid film hydration (TLH) with down-sizing performed by extrusion for comparison purposes. We demonstrated double the loading capacity of ZnPc into liposomes made by microfluidics compared to TLH/extrusion. Microfluidics resulted in the theranostic nanoliposomes characterized by sizes =2.5x smaller than vesicles prepared by TLH/extrusion. Increased relaxivity was observed for liposomes manufactured by microfluidics compared to TLH, despite a slightly lower Gd chelate recovery. We attributed the improved relaxation to the increased surface area/volume ratio of vesicles and decreased phosphatidylcholine/ZnPc molar ratio, which affected water molecules' diffusion through the liposomal membrane. Finally, we showed photodynamic efficacy of ZnPc loaded into theranostic liposomes in head and neck cancer model, resulting in IC 50 of 0.22 - 0.61 μM, depending on the formulation and cell line used. We demonstrate microfluidics' feasibility to be used for theranostic liposome manufacturing and co-entrapment of therapeutic and imaging components in a single-step process with a high yield., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

The multi-drug resistant bacteria have become a serious problem complicating therapies to such a degree that often the term "post-antibiotic era" is applied to describe the situation. The infections with methicillin-resistant S. aureus, vancomycin-resistant E. faecium, third generation cephalosporin-resistant E. coli, third generation cephalosporin-resistant K. pneumoniae and carbapenem-resistant P. aeruginosa have become commonplace. Thus, the new strategies of infection treatment have been searched for, and one of the approaches is based on photodynamic antimicrobial chemotherapy. Photodynamic protocols require the interaction of photosensitizer, molecular oxygen and light. The aim of this review is to provide a comprehensive overview of photodynamic antimicrobial chemotherapy by porphyrinoid photosensitizers. In the first part of the review information on the mechanism of photodynamic action and the mechanism of the bacteria resistance to the photodynamic technique were described. In the second one, it was described porphyrinoids photosensitizers like: porphyrins, chlorins and phthalocyanines useable in photodynamic bacteria inactivation., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

The photodynamic reaction involves the light-induced generation of an excited state in a photosensitizer molecule (PS), which then results in the formation of reactive oxygen species in the presence of oxygen, or a direct modification of a cellular molecule. Most PSs are porphyrinoids, which are highly lipophilic, and are administered usually in liposomes to facilitate their effective delivery to target cells. The currently available liposomal formulations are Visudyne ® and Fospeg ® . Novel PSs were developed and tested for their photodynamic activity against cancer cells. Several compounds were highly phototoxic to oral cancer cells both in free and liposome-encapsulated form, with nanomolar IC 50 values. The lowest IC 50 s (7-13 nM) were obtained with a PS encapsulated in cationic liposomes.

Three 2-(morpholin-4-yl)ethoxy substituted phthalocyanines were synthesized and characterized. Phthalocyanine derivatives revealed moderate to high quantum yields of singlet oxygen production depending on the solvent applied (e.g., in DMF ranging from 0.25 to 0.53). Their photosensitizing potential for photodynamic therapy was investigated in an in vitro model using cancer cell lines. Biological test results were found particularly encouraging for the zinc(II) phthalocyanine derivative possessing two 2-(morpholin-4-yl)ethoxy substituents in nonperipheral positions. Cells irradiated for 20 min at 2 mW/cm(2) revealed the lowest IC50 value at 0.25 μM for prostate cell line (PC3), whereas 1.47 μM was observed for human malignant melanoma (A375) cells. The cytotoxic activity in nonirradiated cells of novel phthalocyanine was found to be very low. Moreover, the cellular uptake, localization, cell cycle, apoptosis through an ELISA assay, and immunochemistry method were investigated in LNCaP cells. Our results showed that the tested photosensitizer possesses very interesting biological activity, depending on experimental conditions.

Viruses cause many diseases in humans from the rather innocent common cold to more serious or chronic, life-threatening infections. The long-term side effects, sometimes low effectiveness of standard pharmacotherapy and the emergence of drug resistance require a search for new alternative or complementary antiviral therapeutic approaches. One new approach to inactivate microorganisms is photodynamic antimicrobial chemotherapy (PACT). PACT has evolved as a potential method to inactivate viruses. The great challenge for PACT is to develop a methodology enabling the effective inactivation of viruses while leaving the host cells as untouched as possible. This review aims to provide some main directions of antiviral PACT, taking into account different photosensitizers, which have been widely investigated as potential antiviral agents. In addition, several aspects concerning PACT as a tool to assure viral inactivation in human blood products will be addressed.

Photodynamic therapy exploits the light-activation of a photosensitizer to cause cytotoxicity. Liposomes can be used to deliver hydrophobic photosensitizers to bacteria. Positively charged dioleoyltrimethylammoniumpropane:palmitoyloleoylphosphatidylcholine (1:1) liposomes bound quantitatively to the periodontal pathogen, Porphyromonas gingivalis. Following illumination, free and liposomal zinc phthalocyanine reduced the colony-forming unit (CFU) to 65 percent and 23 percent of controls, respectively. Thus, localization of the photosensitizer at the surface of bacteria via liposome binding enhanced the photodynamic cytotoxicity of zinc phthalocyanine.

The complete eradication of various targets, such as infectious agents or cancer cells, while leaving healthy host cells untouched, is still a great challenge faced in the field of medicine. Photodynamic therapy (PDT) seems to be a promising approach for anticancer treatment, as well as to combat various dermatologic and ophthalmic diseases and microbial infections. The application of liposomes as delivery systems for porphyrinoids has helped overcome many drawbacks of conventional photosensitizers and facilitated the development of novel effective photosensitizers that can be encapsulated in liposomes. The development, preclinical studies and future directions for liposomal delivery of conventional and novel photosensitizers are reviewed., (Copyright © 2013 Elsevier Ltd. All rights reserved.)