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Accumulation studies have found that adipose-derived stem cell (ADSC) exosomes have anti-oxidant and anti-inflammatory characteristics. The current study verified their therapeutic potential to elucidate mechanisms of ADSC exosome actions in ultraviolet B (UVB) light-induced skin injury. Exosomes were isolated from ADSCs and hypoxic pretreated ADSCs. Next-generation sequencing (NGS) was applied to characterize differential mRNA expression. A UV-induced mice skin injury model was generated to investigate therapeutic effects regarding the exosomes via immunofluorescence and ELISA analysis. Regulatory mechanisms were illustrated using luciferase report analysis and in vitro experiments. The results demonstrated that exosomes from hypoxic pretreated ADSCs (HExos) inhibited UVB light-induced vascular injury by reversing reactive oxygen species, inflammatory factor expression and excessive collagen degradation. NGS showed that HExos inhibits UV-induced skin damage via GLRX5 delivery, while GLRX5 downregulation inhibited the therapeutic effect of HExos on UV-induced skin damage. GLRX5 upregulation increased the protective Exo effect on UV-induced skin and EPC damage by inhibiting ferroptosis, inflammatory cytokine expression and excessive collagen degradation. Therefore, the data indicate that HExos attenuate UV light-induced skin injury via GLRX5 delivery and ferroptosis inhibition. [ABSTRACT FROM AUTHOR]

Noninvasive treatments for terminal cancer patients constitute a new trend in tumor treatment. Therefore, phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has attracted considerable interest. Light and a photosensitizer (PS) are employed in both treatment methods. For PDT, the PS generates reactive oxygen species (ROS) when exposed to light, whereas for PTT, the PS generates heat. In this regard, the systematic design of new PSs has become an active area of phototherapy research in an effort to solve the problems associated with conventional PSs. In the past decade, activatable and heavy‐atom‐free PSs have become significant research areas. Therefore, we discuss our recent contributions to the PDT and PTT in this account. [ABSTRACT FROM AUTHOR]

The accumulation of photosensitizers (PSs) in lesion sites but not in other organs is an important challenge for efficient image guiding in photodynamic therapy. Cancer cells are known to express a significant number of albumin-binding proteins that take up albumin as a nutrient source. Here, we converted albumin to a novel BODIPY-like PS by generating a tetrahedral boron environment via a flick reaction. The formed albumin PS has almost the same 3-dimensional structural feature as free albumin because binding occurs at Sudlow Site 1, which is located in the interior space of albumin. An i.v. injection experiment in tumor-bearing mice demonstrated that the human serum albumin PS effectively accumulated in cancer tissue and, more surprisingly, albumin PS accumulated much more in the cancer tissue than in the liver and kidneys. The albumin PS was effective at killing tumor cells through the generation of reactive oxygen species under light irradiation. The crystal structure of the albumin PS was fully elucidated by X-ray crystallography; thus, further tuning of the structure will lead to novel physicochemical properties of the albumin PS, suggesting its potential in biological and clinical applications. We report a novel strategy in which albumin is used as a tumor-targeting photosensitizer (PS) by generating a tetrahedral boron environment via flick binding, which results in tighter binding than normal noncovalent bonds. An i.v. injection experiment in tumor-bearing mice demonstrated that the albumin PS effectively accumulated in cancer tissue and, more surprisingly, albumin PS accumulates much more in the cancer tissue than in the kidneys and liver. The albumin PS was effective at killing tumor cells through the generation of ROS under light irradiation. [Display omitted] [ABSTRACT FROM AUTHOR]

An effective strategy to engineer selective photodynamic agents to surmount bacterial‐infected diseases, especially Gram‐positive bacteria remains a great challenge. Herein, we developed two examples of compounds for a proof‐of‐concept study where reactive differences in reactive oxygen species (ROS) can induce selective ablation of Gram‐positive bacteria. Sulfur‐replaced phenoxazinium (NBS‐N) mainly generates a superoxide anion radical capable of selectively killing Gram‐positive bacteria, while selenium‐substituted phenoxazinium (NBSe‐N) has a higher generation of singlet oxygen that can kill both Gram‐positive and Gram‐negative bacteria. This difference was further evidenced by bacterial fluorescence imaging and morphological changes. Moreover, NBS‐N can also successfully heal the Gram‐positive bacteria‐infected wounds in mice. We believe that such reactive differences may pave a general way to design selective photodynamic agents for ablating Gram‐positive bacteria‐infected diseases. [ABSTRACT FROM AUTHOR]

Phototheranostic nanoplatforms are of particular interest for cancer diagnosis and imaging‐guided therapy. Herein, we develop a supramolecular approach to fabricate a nanostructured phototheranostic agent through the direct self‐assembly of two water‐soluble phthalocyanine derivatives, PcS4 and PcN4. The nature of the molecular recognition between PcS4 and PcN4 facilitates the formation of nanostructure (PcS4‐PcN4) and consequently enables the fabrication of PcS4‐PcN4 with completely quenched fluorescence and reduced singlet oxygen generation, leading to the high photoacoustic and photothermal activity of PcS4‐PcN4. In vivo evaluations suggest that PcS4‐PcN4 could not only efficiently visualize a tumor with high contrast through whole‐body photoacoustic imaging but also enable excellent photothermal therapy for cancer. [ABSTRACT FROM AUTHOR]

Multidrug-resistant (MDR) gram-positive bacteria are an inevitable source of infection for hospitalized patients and one of the reasons for the increased proportion of severe diseases. Therefore, constructing smart agents for specific and effective combating infections in vivo caused by MDR gram-positive strains is very urgent. Herein, we reported a structure-oriented design strategy (SODS) to reasonably construct an organic photo-antimicrobial near-infrared (NIR) AIEgen BDPTV equipped with a phenylboronic acid moiety, which could be bound to the thick peptidoglycan layer of MDR gram-positive bacteria, resulting in a tight distribution with the cell wall in a confined space. Compared to the contrast compounds DQVTA and DPTVN , upon photoirradiation of AIEgen BDPTV , the generation of abundant and highly toxic reactive oxygen species (ROS) irreversibly destroys MDR gram-positive bacteria through photodynamic therapy, which is better than commercial photosensitizers (including methylene blue, chlorin e6, and protoporphyrin IX) and antibiotic (cefoxitin). As a proof of concept, in vitro experimental results showed that methicillin-resistant Staphylococcus aureus (MRSA) were completely killed using AIEgen BDPTV. More importantly, AIEgen BDPTV was capable of successfully combating MRSA -infected wounds of mice, but not Escherichia coli (E. coli)-infected wounds. We hope that this strategy could provide a new method to design powerful AIEgens to avoid the overuse and misuse of antibiotics. In this contribution, based on structure-oriented design strategy, a smart AIEgen BDPTV was rationally developed to selectively combat gram (+) multidrug-resistant bacteria in vivo. [Display omitted] [ABSTRACT FROM AUTHOR]

The redox-responsive nanoparticle (NanoP-ss-BA) is designed by linking the porphyrin derivative (P) to the naturally occurring betulinic acid (BA) through a disulphide bond. A GSH triggered disassembly of NanoP-ss-BA effectively promotes a singlet oxygen (1O 2) production, but also releases lipophilic anticancer drug, BA in situ. Beside this, high phototoxicity of NanoP-ss-BA serves it as a good candidate for photodynamic therapy (PDT). When the prepared NanoP-ss-BA is exposed to a reductive environment, the cleavage of the disulphide bonds facilitates the disassembly of nanostructure causing a release of P and BA , and restores the photoactivity of P. In vitro cell studies revealed that NanoP-ss-BA exhibits significant phototoxicity against cancer cells (4T1). [Display omitted] • Designing redox-responsive nanoparticles by linking porphyrin to betulinic acid through a disulphide bond. • Designing a triggered disassembly of NanoP-ss-BA that promotes singlet oxygen. • Suggesting NanoP-ss-BA as a candidate for photodynamic therapy. [ABSTRACT FROM AUTHOR]