Photoredox catalysis may be a general mechanism in photodynamic therapy.

Elucidating the underlying photochemical mechanisms of action (MoA) of photodynamic therapy (PDT) may allow its efficacy to be improved and could set the stage for the development of new classes of PDT photosensitizers. Here, we provide evidence that "photoredox catalysis in cells," wherein key electron transport pathways are disrupted, could constitute a general MoA associated with PDT. Taking the cellular electron donor nicotinamide adenine dinucleotide as an example, we have found that well-known photosensitizers, such as Rose Bengal, BODIPY, phenoselenazinium, phthalocyanine, and porphyrin derivatives, are able to catalyze its conversion to NAD+. This MoA stands in contrast to conventional type I and type II photoactivation mechanisms involving electron and energy transfer, respectively. A newly designed molecular targeting photocatalyst (termed CatER) was designed to test the utility of this mechanism-based approach to photosensitizer development. Photoexcitation of CatER induces cell pyroptosis via the caspase 3/GSDME pathway. Specific epidermal growth factor receptor positive cancer cell recognition, high signal-to-background ratio tumor imaging (SBRTI = 12.2), and good tumor growth inhibition (TGI = 77.1%) are all hallmarks of CatER. CatER thus constitutes an effective near-infrared pyroptotic cell death photo-inducer. We believe the present results will provide the foundation for the synthesis of yet-improved phototherapeutic agents that incorporate photocatalytic chemistry into their molecular design.

Photoinduced Cuproptosis with Tumor-Specific for Metastasis-Inhibited Cancer Therapy.

Cuproptosis is a novel form of regulated cell death which guarantees to increase the efficacy of existing anticancer treatments that employ traditional apoptotic therapeutics. However, reducing the amount of undesirable Cu ions released in normal tissue and maximizing Cu-induced cuproptosis therapeutic effects at tumor sites are the major challenges. In this study, exploiting the chemical properties of copper ionophores and the tumor microenvironment, a novel method is developed for controlling the valence of copper ions that cause photoinduced cuproptosis in tumor cells. CJS-Cu nanoparticles (NPs) can selectively induce cuproptosis after cascade reactions through H2 O2 -triggered Cu2+ release, photoirradiation-induced superoxide radical (∙O2 - ) generation, and reduction of Cu2+ to Cu+ by ∙O2 - . The generated reactive oxygen species can result in glutathione depletion and iron-sulfur cluster protein damage and further augmented cuproptosis. CJS-Cu NPs effectively suppressed tumor growth and downregulated the expression of metastasis-related proteins, contributing to the complete inhibition of lung metastasis. Ultimately, this study suggests novel avenues for the manipulation of cellular cuproptosis through photochemical reactions.

Red-Light Triggered H-Abstraction Photoinitiators for the Efficient Oxygen-Independent Therapy of Hypoxic Tumors.

The clinical application of photodynamic therapy (PDT) is limited by oxygen-dependence and side effects caused by photosensitizer residues. Photoinitiators based on the H-abstraction reaction can address these challenges because they can generate alkyl radical-killing cells independently of oxygen and undergo rapid bleaching following H-abstraction. Nonetheless, the development of photoinitiators for PDT has been impeded by the absence of effective design strategies. Herein, we have developed aryl-ketone substituted cyanine (ACy-R), the first red-light triggered H-abstraction photoinitiators for hypoxic cancer therapy. These ACy-R molecules inherited the near-infrared absorption of cyanine dye, and aryl-ketone modification imparted H-abstraction capability. Experimental and quantum calculations revealed that modifying the electron-withdrawing groups of the aryl (e.g., ACy-5F) improved the contribution of the O atom to the photon excitation process promoting intersystem crossing and H-abstraction ability. Particularly, ACy-5F rapidly penetrated cells and enriched in the endoplasmic reticulum. Even under severe hypoxia, ACy-5F initiated red-light induced H-abstraction with intracellular biomolecules, inducing necroptosis and ferroptosis. Moreover, ACy-5F was degraded after H-abstraction, thus avoiding the side effects of long-term phototoxicity after therapy. This study not only provides a crucial molecular tool for hypoxic tumors therapy, but also presents a promising strategy for the development of multifunctional photosensitizers and photoinitiators.

ER-Targeting Cyanine Dye as an NIR Photoinducer to Efficiently Trigger Photoimmunogenic Cancer Cell Death.

Endoplasmic reticulum (ER) stress, caused by overproduction of reactive oxygen species (ROS), has been shown to be responsible for immunogenic cell death (ICD). Seeking ROS generator targeting ER is an optimal solution to efficiently induce ER stress. Despite clear indications of demand for ER-targeting photosensitizer, the alternative chemical tools remain limited. Herein, the first ER-localizable ICD photoinducer using thio-pentamethine cyanine dye (TCy5) to induce ER stress under mild near-infrared (NIR) irradiation has been developed. Within the ICD photoinducer design, polyfluorinated TCy5-Ph-3F possesses a selective tropism to ER accumulation and superior ROS generation capability in both normoxia and hypoxia conditions, which benefit from its low singlet-triplet gaps. Under NIR irradiation, cancer cells stained by TCy5-Ph-3F will lead to ER stress and induce massive emission of damage-associated molecular patterns, including calreticulin and heat-shock protein 70 exposure, high mobility group box 1 efflux, and adenosine triphosphate secretion. Dendritic cells maturation and CD8+ T cells activation in vivo also highlight the effectiveness. Therefore, the growth of abscopal tumors was substantially suppressed by the primary tumor treated with TCy5-Ph-3F and NIR irradiation. These results confer practical applicability that could provide a guideline for designing efficient ICD photoinducers, which will enable expanding organic molecular applications for cancer immunotherapy.

Urea-Bond Scission Induced by Therapeutic Ultrasound for Biofunctional Molecule Release.

Ultrasound-triggered remote control of biomolecular functions in cells provides unique advantages for us to interrogate nature. However, strategies to design therapeutic ultrasound-responsive functional molecules remain elusive, and rare ultrasound-cleavable chemical bonds have been developed to date. Herein, therapeutic ultrasound (1 MHz)-induced scission of urea bonds for drug release is demonstrated for the first time. Such a transformation has been verified to be initiated by hydroxyl radicals generated in the interior of cavitation bubbles, occurring specifically at the cavitation bubble-liquid interface. A series of urea-bond-containing prodrugs based on methylene blue (MB), namely MBUs, are designed. Upon sonication with low-intensity therapeutic ultrasound, the urea bonds linked with primary amines can be selectively cleaved, and free MB is released in a physiologically relevant environment, accompanied by recovered absorbance, fluorescence, and photosensitivity. Moreover, an FDA-approved alkylating agent (i.e., melphalan) bearing urea bond is also developed (MBU-Mel), successfully achieving ultrasound-triggered drug release in deep-seated cancer cells (mimic with 1 cm pigskin), showing the scalability of our ultrasound-responsive molecule platform in bioactive molecules release. This may set the starting point for therapeutic ultrasound-induced drug release, making a forward step in "sonopharmacology".

An Approach to Developing Cyanines with Simultaneous Intersystem Crossing Enhancement and Excited-State Lifetime Elongation for Photodynamic Antitumor Metastasis.

Heavy-atom-based photosensitizers usually exhibit shortened triplet-state lifetimes, which is not ideal for hypoxic tumor photodynamic therapy. Although several heavy-atom-free photosensitizers possess long triplet-state lifetimes, the clinical applicability is limited by their short excitation wavelengths, poor photon capture abilities, and intrinsically hydrophobic structures. Herein we developed a novel NIR heavy-atom-free photosensitizer design strategy by introducing sterically bulky and electron-rich moieties at the meso position of the pentamethine cyanine (Cy5) skeleton, which simultaneously enhanced intersystem crossing (ISC) and prolonged excited-state lifetime. We found that the 1O2 generation ability is directly correlated to the electron-donating ability of the meso substituent in cyanine, and the excited-state lifetime was simultaneously much elongated when the substituents were anthracene derivatives substituted at the 9-position. Our star compound, ANOMe-Cy5, exhibits intense NIR absorption, the highest 1O2 quantum yield (4.48-fold higher than Cy5), the longest triplet-state lifetime (9.80-fold longer than Cy5), and lossless emission intensity (nearly no change compared with Cy5). Such excellent photophysical properties coupled with its inherently cationic and hydrophilic nature enable the photosensitizer to realize photoablation of solid tumor and antitumor lung metastasis. This study highlights the design of a new generation of NIR photosensitizers for imaging-guided photodynamic cancer treatment.

Emerging Design Principle of Near-Infrared Upconversion Sensitizer Based on Mitochondria-Targeted Organic Dye for Enhanced Photodynamic Therapy.

Upconversion luminescent (UCL) triggered photodynamic therapy (PDT) affords superior outcome for cancer treatment. However, conventional UCL materials which all work by a multiphoton absorption (MPA) process inevitably need extremely high power density far over the maximum permissible exposure (MPE) to laser. Here, a one-photon absorption molecular upconversion sensitizer Cy5.5-Br based on frequency upconversion luminescent (FUCL) is designed for PDT. The unusual super heavy atom effect (SHAE) in Cy5.5-Br strongly enhances its spin-orbit coupling (0.23 cm-1 ), triplet quantum yield (11.1 %) and triplet state lifetime (18.8 µs) while the potential hot-band absorption of Cy5.5-Br is well maintained. Importantly, Cy5.5-Br can efficiently target the tumour site and kill cancer cells by destroying mitochondria under a biosafety MPE to 808 nm laser. The photostability and antitumor results are obviously superior to that of a Stokes process. This work provides a design criterion for FUCL dyes to realize effective PDT upon a biosafety optical density, possibly bringing more clinical benefits than conventional MPA materials.

Oxygen-Dependent Regulation of Excited-State Deactivation Process of Rational Photosensitizer for Smart Phototherapy.

It remains a considerable challenge to realize complete tumor suppression and avoid tumor regrowth by rational design of photosensitizers (PSs) to improve their photon utilization. In this Article, we provide a molecular design (Icy-NBF) based on the oxygen-content-regulated deactivation process of excited states. In the presence of overexpressed nitroreductase in hypoxic cancer cells, Icy-NBF is reduced and converted into a molecule with the same skeleton (Icy-NH2), in which the deactivation of the PS under 808 nm light irradiation proceeds via a different pathway: the excited states deactivation pathway of Icy-NBF involves radiative transition and energy transfer between Icy-NBF and O2; as for Icy-NH2, the deactivation pathway is attributed to non-radiative relaxation. By varying the O2 concentration in tumor cells, the therapeutic mechanism of Icy-NBF under 808 nm light irradiation can be switched between photodynamic and photothermal therapies, which maximizes the advantages of phototherapies with no tumor regrowth. Our study provides help in designing of smart PSs with improvement of photon utilization for efficient tumor photoablation.

Aminopeptidase N Activatable Fluorescent Probe for Tracking Metastatic Cancer and Image-Guided Surgery via in Situ Spraying.

The recurrence of malignant tumors is mostly caused by incompleted surgical resection. Especially, it is difficult for surgeons to detect and accurately remove metastatic tumors by predominantly using visual examination and palpation owing to the lack of effective means to specifically distinguish the boundary range between normal and tumor tissues. Thus, the development of activated fluorescent probe with superior tumor-to-normal (T/N) tissue ratios is particularly urgent in clinics. In view of CD13/aminopeptidase N (APN) regarded as a cancer-specific biomarker, mediating with progression, invasion, and migration of malignant tumor, herein, we reported an APN-responsive fluorescent probe YH-APN and demonstrated its application to distinguish cancer cells. Through in situ spraying manner, fluorescent superior tumor-to-normal (T/N) tissue ratios (subcutaneous transplantation tumor, 13.86; hepatic metastasis, 4.42 and 6.25; splenic metastasis, 4.99) were achieved. More importantly, we have demonstrated the ability to image metastasis tumor tissue less than 1 mm in diameter, highlighting the potential for this probe to be used as a tool in surgical resection. This research may spur the use of enzyme-activatable fluorescent probes for the progress of tumor diagnosis and image-guided surgery (IGS).

Superoxide Radical Photogenerator with Amplification Effect: Surmounting the Achilles' Heels of Photodynamic Oncotherapy.

Strong oxygen dependence, poor tumor targeting, and limited treatment depth have been considered as the "Achilles' heels" facing the clinical usage of photodynamic therapy (PDT). Different from common approaches, here, we propose an innovative tactic by using photon-initiated dyad cationic superoxide radical (O2-•) generator (ENBOS) featuring "0 + 1 > 1" amplification effect to simultaneously overcome these drawbacks. In particular, by taking advantage of the Förster resonance energy transfer theory, the energy donor successfully endows ENBOS with significantly enhanced NIR absorbance and photon utility, which in turn lead to ENBOS more easily activated and generating more O2-• in deep tissues, that thus dramatically intensifies the type I PDT against hypoxic deep tumors. Moreover, benefiting from the dyad cationic feature, ENBOS achieves superior "structure-inherent targeting" abilities with the signal-to-background ratio as high as 25.2 at 48 h post intravenous injection, offering opportunities for accurate imaging-guided tumor treatment. Meanwhile, the intratumoral accumulation and retention performance are also markedly improved (>120 h). On the basis of these unique merits, ENBOS selectively inhibits the deep-seated hypoxic tumor proliferation at a low light-dose irradiation. Therefore, this delicate design may open new horizons and cause a paradigm change for PDT in future cancer therapy.

Defects Promote Ultrafast Charge Separation in Graphitic Carbon Nitride for Enhanced Visible-Light-Driven CO2 Reduction Activity.

Fundamental photocatalytic limitations of solar CO2 reduction remain due to low efficiency, serious charge recombination, and short lifetime of catalysts. Herein, two-dimensional graphitic carbon nitride nanosheets with nitrogen vacancies (g-C3 Nx ) located at both three-coordinate N atoms and uncondensed terminal NHx species were prepared by one-step tartaric acid-assistant thermal polymerization of dicyandiamide. Transient absorption spectra revealed that the defects in g-C3 N4 act as trapped states of charges to result in prolonged lifetimes of photoexcited charge carriers. Time-resolved photoluminescence spectroscopy revealed that the faster decay of charges is due to the decreased interlayer stacking distance in g-C3 Nx in favor of hopping transition and mobility of charge carriers to the surface of the material. Owing to the synergic virtues of strong visible-light absorption, large surface area, and efficient charge separation, the g-C3 Nx nanosheets with negligible loss after 15 h of photocatalysis exhibited a CO evolution rate of 56.9 µmol g-1 h-1 under visible-light irradiation, which is roughly eight times higher than that of pristine g-C3 N4 . This work presents the role of defects in modulating light absorption and charge separation, which opens an avenue to robust solar-energy conversion performance.

De Novo Design of Phototheranostic Sensitizers Based on Structure-Inherent Targeting for Enhanced Cancer Ablation.

Structure-inherent targeting (SIT) agents are of particular importance for clinical precision medicine; however, there still exists a great lack of SIT phototheranostics for simultaneous cancer diagnosis and targeted photodynamic therapy (PDT). Herein, for the first time, we propose a "one-for-all" strategy by using the Förster resonance energy transfer (FRET) mechanism to construct such omnipotent SIT phototheranostics. Of note, this novel tactic can not only endow conventional sensitizers with highly effective native tumor-targeting potency but also simultaneously improve their photosensitization activities, resulting in dramatically boosted therapeutic index. After intravenous injection of the prepared SIT theranostic, the neoplastic sites are distinctly "lighted up" and distinguished from neighboring tissues, showing a near-infrared signal-to-background ratio value as high as 12.5. More importantly, benefiting from the FRET effect, markedly amplified light-harvesting ability and 1O2 production are demonstrated. Better still, other favorable features are also simultaneously achieved, including specific mitochondria anchoring, augmented cellular uptake (>13-fold), as well as ideal biocompatibility, all of which allow orders-of-magnitude promotion in anticancer efficiency both in vitro and in vivo. We believe this one-for-all SIT platform will provide a new idea for future cancer precision therapy.

Near-Infrared Light-Initiated Molecular Superoxide Radical Generator: Rejuvenating Photodynamic Therapy against Hypoxic Tumors.

Hypoxia, a quite universal feature in most solid tumors, has been considered as the "Achilles' heel" of traditional photodynamic therapy (PDT) and substantially impairs the overall therapeutic efficacy. Herein, we develop a near-infrared (NIR) light-triggered molecular superoxide radical (O2-•) generator (ENBS-B) to surmount this intractable issue, also reveal its detailed O2-• action mechanism underlying the antihypoxia effects, and confirm its application for in vivo targeted hypoxic solid tumor ablation. Photomediated radical generation mechanism study shows that, even under severe hypoxic environment (2% O2), ENBS-B can generate considerable O2-• through type I photoreactions, and partial O2-• is transformed to high toxic OH· through SOD-mediated cascade reactions. These radicals synergistically damage the intracellular lysosomes, which subsequently trigger cancer cell apoptosis, presenting a robust hypoxic PDT potency. In vitro coculture model shows that, benefiting from biotin ligand, ENBS-B achieves 87-fold higher cellular uptake in cancer cells than normal cells, offering opportunities for personalized medicine. Following intravenous administration, ENBS-B is able to specifically target to neoplastic tissues and completely suppresses the tumor growth at a low light-dose irradiation. As such, we postulated this work will extend the options of excellent agents for clinical cancer therapy.

Recognition of Exogenous and Endogenous Nitroxyl in Living Cells via a Two-Photon Fluorescent Probe.

Nitroxyl (HNO), one electron reduced and protonated form of nitric oxide (NO), plays vital in various biological functions and pharmacological activities, such as mediating ß-agonist dobutamine, inhibiting the activity of enzyme and treating cardiovascular diseases. However, the accurate mechanism of HNO in living cells is not thoroughly understood due to lacking of effective methods. In this work, a novel two-photon fluorescent probe TP-HNO was designed and synthesized based on 6-hydroxyl-quinonline-2-benzothiazole derivatives through introducing 2-(diphenylphosphino)benzoate as the ideal HNO recognition unit, which demonstrated the merits of outstanding selectivity, excellent sensitivity (DL 0.19 µM) and rapid response (20 min). In addition, owing to the high cell permeability and low biotoxicity of probe TP-HNO, it was successfully used for the qualitative and bioimaging of exogenous and endogenous nitroxyl concentration fluctuations in living cells via a two-photon laser confocal fluorescence microscopy, respectively, which is of importance for revealing the biological of HNO in the further.

Single-molecule spectroscopy and femtosecond transient absorption studies on the excitation energy transfer process in ApcE(1-240) dimers.

ApcE(1-240) dimers with one intrinsic phycocyanobilin (PCB) chromophore in each monomer that is truncated from the core-membrane linker (ApcE) of phycobilisomes (PBS) in Nostoc sp. PCC 7120 show a sharp and significantly red-shifted absorption. Two explanations either conformation-dependent Förster resonance energy transfer (FRET) or the strong exciton coupling limit have been proposed for red-shifted absorption. This is a classic example of the special pair in the photosynthetic light harvesting proteins, but the mechanism of this interaction is still a matter of intense debate. We report the studies using single-molecule and transient absorption spectra on the interaction in the special pair of ApcE dimers. Our results demonstrate the presence of conformation-dependent FRET between the two PCB chromophores in ApcE dimers. The broad distributions of fluorescence intensities, lifetimes and polarization difference from single-molecule measurements reveal the heterogeneity of local protein-pigment environments in ApcE dimers, where the same molecular structures but different protein environments are the main reason for the two PCB chromophores with different spectral properties. The excitation energy transfer rate between the donor and the acceptor about (110 ps)(-1) is determined from transient absorption measurements. The red-shifted absorption in ApcE dimers could result from more extending conformation, which shows another type of absorption redshift that does not depend on strong exciton coupling. The results here stress the importance of conformation-controlled spectral properties of the chemically identical chromophores, which could be a general feature to control energy/electron transfer, widely existing in the light harvesting complexes.

Energy transfer and spectroscopic characterization of a perylenetetracarboxylic diimide (PDI) hexamer.

We report a comprehensive study on a newly synthesized perylenetetracarboxylic diimide (PDI) hexamer together with its corresponding monomer and dimer by means of steady-state absorption and fluorescence as well as femtosecond broadband transient absorption measurements. The structure of the PDI hexamer is nearly arranged in a 3-fold symmetry by three identical and separated dimers. This unique structure makes the excited state energy relaxation processes more complex due to the existence of two different intramolecular interactions: a strong interaction between face-to-face PDIs in dimers and a relatively weak interaction between the three separated PDI dimers. The steady-state spectra and the ground state structural optimization show that the steric effect plays a dominant role in keeping the formation of the face-to-face stacked PDI-dimer within the PDI-hexamer, indicating that some level of a pre-associated excimer had formed already in the ground state for the dimer in the hexamer. Femtosecond transient absorption experiments on the PDI hexamer reveal a fast (∼200 fs) localization process and a sequential relaxation to a pre-associated excimer trap state from the delocalized exciton state with about 1.2 ps after the initially delocalized excitation. Meanwhile, excitation energy transfer among the three separated dimers within the PDI-hexamer is also revealed by the anisotropic femtosecond pump-probe transient experiments, where the hopping time is about 2.8 ps. A relaxed excimer state is further formed in 7.9 ps after energy hopping and conformational relaxation.

Ultrafast relaxation dynamics of phosphine-protected, rod-shaped Au20 clusters: interplay between solvation and surface trapping.

The exact interaction between Au cores and surface ligands remains largely unknown because of the complexity of the structure and chemistry of ligand/Au-core interfaces in ligand-protected Au nanoclusters (AuNCs), which are commonly found in many organic-inorganic complexes. Here, femtosecond transient absorption measurement of the excited-state dynamics of a newly synthesized phosphine-protected cluster [Au20(PPhpy2)10Cl4]Cl2 (1) is reported. Intramolecular charge transfer (ICT) from the Au core to the peripheral ligands was identified. Furthermore, we found that solvation strongly affected ICT at ligand/Au-core interfaces while by choosing several typical alcoholic solvents with different intrinsic solvation times, we successfully observed that excited-state relaxation dynamics together with displacive excited coherent oscillation of Au20 clusters were significantly modulated through the competition between solvation and surface trapping. The results provide a fundamental understanding of the structure-property relationships of the solvation-dependent core-shell interaction of AuNCs for the potential applications in catalysis, sensing and nanoelectronics.

Activating Iterative Revolutions of the Cancer-Immunity Cycle in Hypoxic Tumors with a Smart Nano-Regulator.

The activation of sequential events in the cancer-immunity cycle (CIC) is crucial for achieving effective antitumor immunity. However, formidable challenges, such as innate and adaptive immune resistance, along with the off-target adverse effects of nonselective immunomodulators, persist. In this study, a tumor-selective nano-regulator named PNBJQ has been presented, focusing on targeting two nonredundant immune nodes: inducing immunogenic cancer cell death and abrogating immune resistance to fully activate endogenous tumor immunity. PNBJQ is obtained by encapsulating the immunomodulating agent JQ1 within a self-assembling system formed by linking a Type-I photosensitizer to polyethylene glycol through a hypoxia-sensitive azo bond. Benefiting from the Type-I photosensitive mechanism, PNBJQ triggers the immunogenic cell death of hypoxic tumors under near-infrared (NIR) light irradiation. This process resolves innate immune resistance by stimulating sufficient cytotoxic T-lymphocytes. Simultaneously, PNBJQ smartly responds to the hypoxic tumor microenvironment for precise drug delivery, adeptly addressing adaptive immune resistance by using JQ1 to downregulate programmed death ligand 1 (PD-L1) and sustaining the response of cytotoxic T lymphocytes. The activatable synergic photoimmunotherapy promotes an immune-promoting tumor microenvironment by activating an iterative revolution of the CIC, which remarkably eradicates established hypoxic tumors and suppresses distal lesions under low light dose irradiation.

Lipid Droplet Targeting Type I Photosensitizer for Ferroptosis via Lipid Peroxidation Accumulation.

As an iron-dependent lipid peroxidation (LPO) mediated cell death pathway, ferroptosis offers promises for anti-tumor treatment. Photodynamic therapy (PDT) is an ideal way to generate reactive oxygen species (ROS) for LPO. However, the conventional PDT normally functions on subcellular organelles, such as endoplasmic reticulum, mitochondria, and lysosome, causing rapid cell death before triggering ferroptosis. Herein, the first lipid droplet (Ld)-targeting type I photosensitizer (PS) with enhanced superoxide anion (O2 -· ) production, termed MNBS, is reported. The newly designed PS selectively localizes at Ld in cells, and causes cellular LPO accumulation by generating sufficient O2 -· upon irradiation, and subsequently induces ferroptosis mediated chronical PDT, achieving high-efficient anti-tumor PDT in hypoxia and normoxia. Theoretical calculations and comprehensive characterizations indicate that the Ld targeting property and enhanced O2 -· generation of MNBS originate from the elevated H-aggregation tendency owing to dispersed molecular electrostatic distribution. Further in vivo studies using MNBS-encapsulated liposomes demonstrate the excellent anti-cancer efficacy as well as anti-metastatic activity. This study offers a paradigm of H-aggregation reinforced type I PS to achieve ferroptosis-mediated PDT.

Dipicolylamine-Zn Induced Targeting and Photo-Eliminating of Pseudomonas aeruginosa and Drug-Resistance Gram-Positive Bacteria.

The emergence of drug-resistant bacteria, particularly resistant strains of Gram-negative bacteria, such as Pseudomonas aeruginosa, poses a significant threat to public health. Although antibacterial photodynamic therapy (APDT) is a promising strategy for combating drug-resistant bacteria, actively targeted photosensitizers (PSs) remain unknown. In this study, a PS based on dipicolylamine (DPA), known as WZK-DPA-Zn, is designed for the selective identification of P. aeruginosa and drug-resistant Gram-positive bacteria. WZK-DPA-Zn exploits the synergistic effects of DPA-Zn2+ coordination and cellular uptake, which could effectively anchor P. aeruginosa within a brief period (10 min) without interference from other Gram-negative bacteria. Simultaneously, the cationic nature of WZK-DPA-Zn enhances its interaction with Gram-positive bacteria via electrostatic forces. Compared to traditional clinical antibiotics, WZK-DPA-Zn shows exceptional antibacterial activity without inducing drug resistance. This effectiveness is achieved using the APDT strategy when irradiated with white light or sunlight. The combination of WZK-DPA-Zn with Pluronic-based thermosensitive hydrogel dressings (WZK-DPA-Zn@Gel) effectively eliminates mixed bacterial infections and accelerates wound healing, thereby achieving a synergistic effect where "1+1>2." In summary, this study proposes a precise strategy employing DPA-Zn as the targeting moiety of a PS, facilitating the rapid elimination of P. aeruginosa and drug-resistant Gram-positive bacteria using APDT.