Photo- and Sono-Active Food Colorants Inactivating Bacteria.

Food colorants are commonly used as excipients in pharmaceutical and nutraceutical fields, but they have a wide range of other potential applications, for instance, as cytotoxic drugs or mediators of physical antimicrobial treatments. The photodynamic antibacterial activity of several edible food colorants is reported here, including E127, E129, E124, E122, E133, and E150a, alongside Rhein, a natural lipophilic antibacterial and anticancer compound found in medicinal plants. Minimal inhibitory concentration (MIC) values for S. aureus and E. coli showed that E127 and Rhein were effective against both bacteria, while other colorants exhibited low activity against E. coli. In some cases, dark pre-incubation of the colorants with Gram-positive S. aureus increased their photodynamic activity. Adding Rhein to E127 increased the photodynamic activity of the latter in a supportive mode. Optional sensing mechanism pathways of combined E127/Rhein action were suggested. The antibacterial activity of the studied colorants can be ranged as follows: E127/Rhein >> E127 >> E150a > E122 > E124 >> E129 ≈ E133. E127 was also found to exhibit photodynamic properties. Short ultrasonic treatment before illumination caused intensification of E127 photodynamic activity against E. coli when applied alone and especially in combination with Rhein. Food colorants exhibiting photo- and sonodynamic properties may have good potential in food preservation.

Curcumin-Triterpene Type Hybrid as Effective Sonosensitizers for Sonodynamic Therapy in Oral Squamous Cell Carcinoma.

Sonodynamic therapy (SDT) is a non-invasive therapeutic modality in cancer treatment that combines low-intensity ultrasound (US) and sonosensitizers. Tumor cells are destroyed through the synergistic effects of ultrasound and a chemical sonosensitizer. This study focused on the synthesis and in vitro evaluation of the sonodynamic effect of natural curcumin, triterpene oleanolic acid, and their semi-synthetic derivatives on tongue cancer SCC-25 and hypopharyngeal FaDu cell lines. The combination of the tested compounds with sonication showed a synergistic increase in cytotoxicity. In the group of oleanolic acid derivatives, oleanoyl hydrogen succinate (6) showed the strongest cytotoxic effect both in the SCC-25 and FaDu cell lines. Comparing curcumin (4) and its pyrazole derivative (5), curcumin showed a better cytotoxic effect on SCC-25 cells, while curcumin pyrazole was more potent on FaDu cells. The highest sonotherapeutic activity, compared to its individual components, was demonstrated by a structural linker mode hybrid containing both curcumin pyrazole-oleanoyl hydrogen succinate units within one complex molecule (7). This study can be beneficial in the context of new perspectives in the search for effective sonosensitizers among derivatives of natural organic compounds.

Two-Dimensional FePS3 Nanosheets as an Integrative Sonosensitizer/Nanocatalyst for Efficient Nanodynamic Tumor Therapy.

As the emerging modalities for tumor therapy, sonodynamic therapy (SDT) and chemodynamic therapy (CDT) can generate reactive oxygen species (ROS), typically inducing tumor cell apoptosis. However, the construction of more efficient sonosensitizers integrated with excellent Fenton/Fenton-like catalytic activity to improve the synergistic therapeutic effect of SDT and CDT is still highly challenging. In this study, 2D semiconductor FePS3 nanosheets (NSs), as one of the metal phosphorus trichalcogenides for both sonosensitizer and Fenton catalyst, are successfully synthesized via an ultrasonic-assisted liquid phase exfoliation method from bulk FePS3 and further modified with lipoic acid-polyethylene glycol (LA-PEG) to obtain FePS3 -PEG NSs with desirable biocompatibility. The in vitro and in vivo results demonstrate that the engineered FePS3 -PEG NSs induce the combinatorial SDT/CDT effect attributing to the enhanced ROS generation and significant glutathione depletion, which can conduct highly efficient and safe tumor inhibition and prolong the life span of tumor-bearing mice. This work provides the paradigm of semiconductor FePS3 NSs as the integrative sonosensitizer/Fenton nanocatalyst for dual nanodynamic tumor therapy, paving the new way for exploring other 2D metal phosphorus trichalcogenides in biomedicine.

Ultrathin-FeOOH-Coated MnO2 Sonosensitizers with Boosted Reactive Oxygen Species Yield and Remodeled Tumor Microenvironment for Efficient Cancer Therapy.

Sonodynamic therapy (SDT) typically suffers from compromised anticancer efficacy owing to the low reactive oxygen species (ROS) yield and complicated tumor microenvironment (TME) which can consume ROS and support the occurrence and development of tumors. Herein, ultrathin-FeOOH-coated MnO2 nanospheres (denoted as MO@FHO) as sonosensitizers which can not only facilitate ultrasound (US)-triggered ROS but also tune the TME by hypoxia alleviation, H2 O2 consumption as well as glutathione (GSH) depletion are designed. The FeOOH coating will boost the production yield of singlet oxygen (1 O2 ) and hydroxyl radicals (• OH) by inhibiting the recombination of US-initiated electron-hole pairs and Fenton-like reaction, respectively. Additionally, the catalase-like and GSH peroxidase-like activities of MO@FHO nanospheres enable them to break the TME equilibrium via hypoxia alleviation and GSH depletion. The combination of high ROS yield and fundamental destruction of TME equilibrium results in satisfactory antitumor outcomes, as demonstrated by the high tumor suppression efficacy of MO@FHO on MDA-MB-231-tumor-bearing mice. No obvious toxicity is detected to normal tissues at therapeutic doses in vivo. The capability to modulate the ROS production and TME simultaneously can afford new probability for the development of advanced sonosensitizers for synergistic comprehensive cancer therapy.

Magnetic mediators for ultrasound theranostics.

The theranostics paradigm is based on the concept of combining therapeutic and diagnostic modalities into one platform to improve the effectiveness of treatment. Combinations of multiple modalities provide numerous medical advantages and are enabled by nano- and micron-sized mediators. Here we review recent advancements in the field of ultrasound theranostics and the use of magnetic materials as mediators. Several subdisciplines are described in detail, including controlled drug delivery and release, ultrasound hyperthermia, magneto-ultrasonic heating, sonodynamic therapy, magnetoacoustic imaging, ultrasonic wave generation by magnetic fields, and ultrasound tomography. The continuous progress and improvement in theranostic materials, methods, and physical computing models have created undeniable possibilities for the development of new approaches. We discuss the prospects of ultrasound theranostics and possible expansions of other studies to the theranostic context.

Heating Induced by Therapeutic Ultrasound in the Presence of Magnetic Nanoparticles.

The efficiency of ultrasound hyperthermia for anti-cancer treatments such as radiotherapy or chemotherapy can be improved by using sonosensitizers, which are materials that enhance the attenuation and dissipation of acoustic energy. We propose the use of magnetic nanoparticles as sonosensitizers because of their biocompatibility, nontoxicity, and common use in several medical applications. A magnetic material was synthetized and then incorporated in the form of a magnetic fluid in agar tissue-mimicking phantoms. Ultrasound hyperthermia studies were conducted at various ultrasound frequencies and concentrations of magnetic nanoparticles in the phantoms. The theoretical modeling based on a heat transfer equation and the experimental results show good agreement and confirm that the temperature rise during ultrasound heating in tissue-mimicking phantoms doped with sonosensitizers is greater than that in a pure agar phantom. Furthermore, on the basis of Pennes' bio-heat equation, which takes into consideration the blood perfusion and metabolic heat, the thermal dose and lesion shapes after sonication were determined for a hypothetical tissue.