Recent advances of multi-dimensional porphyrin-based functional materials in photodynamic therapy

A Small-Molecule Drug for the Self-Checking of Mitophagy

Mitophagy, particularly in the context of drugs that disrupt mitochondrial membrane potential (MMP), represents a critical focus in pharmacology. However, the discovery and evaluation of MMP-disrupting drugs are often hampered using commercially available marker molecules that target similar or identical zones. These markers can significantly interfere with, obscure, or amplify the functional effects of MMP-targeting drugs, frequently leading to clinical failures. In response to this challenge, we propose a "one-two punch" drug design strategy that integrates both target-zone drug functionality and non-target zone biological reporting within a single small-molecule drug. We have developed a novel proof-of-concept mitophagy self-check drug (MitoSC) that exhibits dual-color and dual-localization properties. The functional component of this system is a variable MitoSC that disrupts mitochondrial membrane potential (MMP) homeostasis, thereby inducing mitophagy. Upon activation, this component transforms into a blue-fluorescent monomer (MitoSC-fun) specifically within the mitochondrial target zone. Concurrently, the biological reporting component is represented by a red-fluorescent monomer (MitoSC-rep) that localizes to lysosomes, the non-target zone. As mitophagy progresses, the fluorescent signals from MitoSC-rep (lysosomes) and MitoSC-fun (mitochondria) converge, enabling real-time monitoring of the mitophagic process. This strategy combines potent drug functionality with robust biological reporting, thereby minimizing interference and eliminating the complexities associated with external detection. Our findings underscore the potential of a single-molecule drug to exert target-zone specific actions while simultaneously providing non-target zone self-checking, offering a new perspective for drug design.

Oxygen self-supplying porphyrinic MOFs to alleviate tumor hypoxia for starvation-amplified photodynamic therapy

An oxygen self-supplying nanoplatform utilizing perfluorocarbon-functionalized porphyrinic MOFs was developed to alleviate tumor hypoxia. This strategy combines external oxygen-delivery with in situ oxygen generation via cascade reactions, resulting in enhanced synergistic effects for both cancer starvation therapy and robust photodynamic therapy.

Mitochondria-localized dinuclear iridium(III) complexes for two-photon photodynamic therapy

Photodynamic therapy (PDT), as a non-invasive cancer treatment, offers significant advantages including high temporal-spatial selectivity, minimal surgical intervention, and low toxicity, thereby garnering considerable research interest from across the world. In this study, we have developed a series of dinuclear cyclometalated Ir(III) complexes as potential two-photon photodynamic anticancer agents. These Ir(III) complexes demonstrate significant two-photon absorption (2PA) cross-sections (σ2 = 66-166 GM) and specifically target mitochondria. Amongst them, N-Ir4 manifests an IC50 value of 2.0 μM and a phototoxicity index (PI) of 24. Under two-photon excitation, N-Ir4 efficiently generates reactive oxygen species (ROS), leading to mitochondrial damage and cell death. Our study reveals drastically enhanced optical properties forged by forming a dinuclear complex bridged by two conjugated rigid planar moieties and sheds light on a potential paradigm to boost 2PA cross-sections.

Enhanced chemodynamic porphyrin-modified magnetite nanoagents: A triple-action strategy for potent antimicrobial therapy and wound healing

The rise of drug-resistant bacteria, including multidrug-resistant (MDR) strains, has exposed the limitations of current antibiotic treatments. Chemodynamic therapy (CDT) has emerged as a promising approach due to its ability to generate reactive oxygen species (ROS) through Fenton or Fenton-like reactions in infection microenvironments (IMEs). However, the short lifespan, limited diffusion range of ·OH, and restricted variety of ROS reduce the effect of CDT. This study developed amine porphyrins (TAPP)-functionalized Fe3O4 nanoparticles (Fe3O4@TAPP NPs) as a multifunctional antibacterial platform. The TAPP layer can not only trap bacteria through electrostatic attraction in acidic environments but also increase the localized heat upon near-infrared (660 nm) excitation, reducing the effective action distance and boosting the production rate of ·OH. Notably, TAPP was covalently bonded to Fe3O4 nanoparticles via its amine groups and the carboxylic groups on Fe3O4, preventing TAPP self-aggregation under physiological conditions, and preserving the PDT effect. Therefore, the TAPP layer on Fe3O4 nanoparticles performs three functions, resolving the three limitations simultaneously to enhance CDT in a triple-action strategy. The developed Fe3O4@TAPP NPs exhibit improved antibacterial efficiency both in vitro and in vivo. Overall, this study provides an innovative strategy to construct an antibacterial nanoplatform for synergistically enhanced CDT antibacterial treatment, exhibiting great potential for future biomedical applications.

Recent Advances in Glutathione Depletion-Enhanced Porphyrin-Based nMOFs for Photodynamic Therapy

Photodynamic therapy has established itself as a clinical treatment for certain superficial cancers by converting oxygen into cytotoxic singlet oxygen to eradicate cancer cells. Porphyrin-based nanoscale metal-organic frameworks have emerged as promising photosensitive platforms due to their ability to prevent the hydrophobic aggregation quenching of porphyrin molecules and enhance accumulation at the tumor site, thereby becoming a focal point in photodynamic materials research. However, the elevated levels of glutathione and other reductive substances within cancer cells can alleviate the oxidative stress induced by singlet oxygen from the photodynamic therapy process, thus protecting intracellular biomolecular structures from damage. Consequently, it is crucial to design functionalized nanoplatforms that integrate glutathione depletion with porphyrin-based metal-organic frameworks to significantly boost photodynamic therapy efficacy. Moreover, the excess glutathione within cells can disrupt the structure of porphyrin-based metal-organic frameworks, which not only increases the capacity of porphyrin molecules to generate singlet oxygen upon light exposure but also aids in the recovery of their fluorescence imaging capabilities. Additionally, this specificity minimizes the photosensitizing harm of porphyrin-based metal-organic frameworks to other normal tissues. This review compiles recent advancements in developing porphyrin-based metal-organic frameworks for enhanced phototherapy through glutathione depletion. It aims to promote the further application of porphyrin-based metal-organic frameworks in phototherapy and provide valuable insights for preclinical applications. By highlighting strategies that improve therapeutic outcomes while maintaining safety profiles, this summary seeks to advance the development of more effective and targeted cancer treatments.

Polycarbonate-Based Polymersome Photosensitizers with Cell-Penetrating Properties for Improved Killing of Cancer Cells

Polymer-based photosensitizers have found various applications in photodynamic therapy (PDT). However, the absence of targeting ability commonly results in a substantial reduction in photosensitizer accumulation at the tumor site, significantly limiting the therapeutic efficacy of the system. In addition, the development of biodegradable polymeric photosensitizers is of critical importance for biological applications. In this work, we present the development of guanidine-functionalized biodegradable photosensitizers based on poly(trimethylene carbonate) (PTMC) block copolymers, which can self-assemble into polymersomes. The presence of guanidine groups on the surface of polymersomes can significantly enhance the cellular uptake efficiency of photosensitizers, thereby improving the intracellular production of reactive oxygen species (ROS). The in vitro study demonstrates that the guanidinylated polymersome photosensitizers can promote the killing of cancer cells compared to unfunctionalized polymersomes in the presence of light irradiation. The guanidine-functionalized PTMC-based polymersome photosensitizers, with the integration of cell-targeting ability and biodegradability, are anticipated to provide a novel strategy for developing advanced biomedical polymer systems for PDT.

Ultrathin 2D Cu-Porphyrin MOF Nanosheet Loaded Fe3O4 Nanoparticles As a Multifunctional Nanoplatform for Synergetic Chemodynamic and Photodynamic Therapy Independent of O2

In this study, we developed a multifunctional nanoplatform to address the limitations of strictly acidic pH for the Fenton reaction involving Fe3O4 and the low efficiency of mono treatments. The hybrid material, Fe3O4@Cu-TCPP, was assembled through hydrophobic interactions of polyvinylpyrrolidone (PVP) coated on its surface. The efficiency of the Fenton reaction using Fe3O4 was significantly enhanced by the photo-Fenton process in the presence of Cu-TCPP. The generation of hydroxyl radicals by Fe3O4@Cu-TCPP was markedly increased under laser irradiation (λ = 660 nm) in solution. Fe3O4@Cu-TCPP demonstrated a robust ability to produce reactive oxygen species through chemodynamic and photodynamic processes independent of that of O2. In vivo experimental results indicated that Fe3O4@Cu-TCPP facilitated T2-weighted magnetic resonance imaging-mediated synergistic chemodynamic and photodynamic therapies in a 4T1 mouse model.

Auto-Deactivation of BODIPY-Derived Type I Photosensitizer Post Photodynamic Therapy under Hypoxia

The long-lasting activity of photosensitizers during photodynamic therapy (PDT) causes excessive damage and arouses great concerns about biosafety. Herein, we synthesized a pyridinium-decorated diiodo-BODIPY compound (PyBDP) and investigated its photosensitizing activity under hypoxic condition in the presence of NADH that is abundant in the mitochondria of hypoxic tumors. The unique property of PyBDP lies in the redox environment-dependent photo-response. At green light exposure, PyBDP is converted into a colorless inactive form by interacting with NADH in a two-step one-electron transfer process. Interestingly, the NADH-dependent hydrogenation of PyBDP is affected by the presence of cytochrome c (Cyt cox) that is an important component of mitochondrial electron transport chain (Mito-ETC), unless Cyt cox is exhausted. Active radical species is produced during the photocatalytic reaction, which adds the understanding of PyBDP-induced photodamage. Therefore, we applied the strategy of auto-deactivation PDT using a BODIPY photosensitizer by tethering triphenylphosphonium to PyBDP. After PDT effect in a type I pathway, the photosensitizer underwent almost entire auto-deactivation in hypoxic HeLa cells. This work paves a way for the development of reductive PDT with enhanced safety and efficacy in fighting hypoxic tumors independent on reactive oxygen species (ROS).

Near-Infrared Photothermal Conversion by Isocorrole and Phlorin Derivatives

Photothermal therapy is a promising strategy for treating tumors and bacterial infections by using light irradiation to locally heat tissues. Metalloisoporphyrinoid materials have been investigated for their use as singlet oxygen photosensitizers for photodynamic therapy but remain underexplored as photothermal agents. Recently, two metallophlorin and two metalloisocorrole materials were found to have strong near-infrared absorbance, with low photoluminescent quantum yields, suggesting high rates of nonradiative decay. Here we demonstrate that when encapsulated into aggregated organic nanoparticles (a-Odots), these materials show high photothermal conversion efficiencies between 67.3 ± 8.4 and 75.7 ± 4.1%. When considered alongside their ability to generate singlet oxygen, these materials may show promise as agents for dual photothermal and photodynamic therapy.

Activatable Porphyrin-Based Sensors, Photosensitizers and Combination Therapeutics

Porphyrins, known as the "pigments of life", have evolved from their natural roles into versatile tools for biomedical applications. The development of activatable porphyrins has significantly expanded their utility, enabling precise responses to a carefully selected target analyte. These advances have broadened their use in imaging, diagnosis, and therapy. These capabilities are driven by activity-based sensing (ABS), which enhances the selectivity and sensitivity to various disease biomarkers. However, their design and implementation are intrinsically complex. This perspective provides an easy-to-follow roadmap that details how such molecules can be developed. Furthermore, we highlight recent progress in ABS-modified porphyrins, focusing on how specific modifications achieve these remarkable properties across various biomedical platforms. The ongoing evolution of activatable porphyrins holds great promise for the development of sophisticated, responsive systems, offering more effective diagnostic and therapeutic tools.

Metal-Assisted Synthesis of Diverse Porphyrinoids by Cyclization of an N-Confused Thia-Pentapyrrane

Oxidation of thia-pentapyrrane S-P4 with terminal β-linked pyrrole and thiophene units in the presence of various metal ions has been found to afford distinct porphyrinoids. Specifically, N-confused thiasapphyrin (1), Cu(III) norrole (2), neo-confused phlorin (3), and p-benzinorrole (4) were obtained, when S-P4 was oxidized with p-chloranil in acetonitrile in the presence of Ni2+, Cu2+, Cd2+, and Co2+, respectively. The structures of 1-4 have been clearly elucidated by NMR spectroscopy, HRMS, and X-ray crystal diffraction (for 2-4). This work indicates that the oxidative cyclization by linking highly reactive β-linked pyrrole unit with less reactive thiophene unit assisted by various metal ions shows great potential in the construction of various novel porphyrinoids.

A Poly(2,7-anthrylene) with peri-Fused Porphyrin Edges

Anthracene has served as an important building block of conjugated polymers with the connecting positions playing a crucial role for the electronic structures. Herein, anthracene units have been coupled through their 2,7-carbons to develop an unprecedented, conjugated polymer, namely, poly(2,7-anthrylene) featuring additional peri-fused porphyrin edges. The synthesis starts from a 2,7-dibromo-9-nickel(II) porphyrinyl-anthracene as the pivotal precursor. Polymerization is achieved by an AA-type Yamamoto coupling, followed by a polymer-analogous oxidative cyclodehydrogenation to obtain a peri-fusion between porphyrin and anthracene moieties. Although further cyclodehydrogenation between the repeating units cannot be achieved in solution, the thermal treatment of the precursor polymer derived from 2,7-dibromo-9-porphyrinyl-anthracene on a metal surface realizes the full cyclodehydrogenation. The difference between solution and on-surface reactivity can be rationalized by the larger dihedral angle between repeat units in solution, which is reduced under the pronounced interaction with the metal surface. The peri-fusion in the title polymer gives rise to a narrow electronic band gap optical absorptions extending far into the near-infrared region. Oligomeric models are synthesized as well to support the analyses of the electronic and photophysical properties.

Electrostatic Force-Enabled Microneedle Patches that Exploit Photoredox Catalysis for Transdermal Phototherapy

Microneedle patches for topical administration of photodynamic therapy (PDT) sensitizers are attractive owing to their safety, selectivity, and noninvasiveness. However, low-efficiency photosensitizer delivery coupled with the limitations of the hypoxic tumor microenvironment remains challenging. To overcome these issues, we developed an effective microneedle patch based on intermolecular electrostatic interactions within a photosensitizer matrix containing a zinc-containing porphyrin analogue, ZnBP (w). This design improved the mechanical strength of the microneedle patch and enhanced the photosensitizer loading efficiency in aqueous environments. A key feature of the system is efficient electron transfer between ZnBP (w) and NADH upon photoirradiation. Electrostatic interactions between ZnBP (w) and NADH were hypothesized to support initial binding and subsequent photoinduced electron transfer, disrupting NADH/NAD+ homeostasis and inducing tumor cell death. The developed microneedle patch demonstrated an antiangiogenesis effect in a vascular malformation model and an antitumor effect in a melanoma mouse model after transdermal administration. This study highlights the benefits of electrostatic interactions in designing microneedle PDT patches and their clinical potential, particularly in reducing systemic phototoxicity.

Surface charge switchable fluorinated small molecular micelles for enhanced photodynamic therapy for bacterial infections

Photodynamic therapy (PDT) employs reactive oxygen species (ROS) from a photosensitizer (PS) under light, inhibiting multi-drug resistance in bacteria. However, hypoxic conditions in infection sites and biofilms challenge PDT efficiency. We developed fluorinated small molecular micelles (PF-CBMs) as PS carriers to address this, relieving hypoxia and enhancing PS penetration into biofilms. Perfluorocarbons in PF-CBMs transport more oxygen due to their excellent oxygen-dissolving capability. Fluorination enhances loading capacity and serum stability, reduces premature release, and improves cellular uptake, to improve PDT efficacy. PF-CBMs, with acid-induced surface charge transformation, exhibit superior biofilm penetration, resulting in increased antibiofilm activity of PDT. Compared to fluorine-free micelles (PC-CBMs), PF-CBMs demonstrate better serum stability, higher drug loading, and reduced premature release, leading to significantly improved antibacterial efficacy in vitro and in vivo. In conclusion, fluorinated micelles with surface charge reversal enhance PDT for antibacterial and antibiofilm applications.

Application of novel silica stabilized on a covalent triazine framework as a highly efficient heterogeneous and recyclable catalyst in the effective green synthesis of porphyrins

In this study, we present the design, synthesis, and utilization of a covalent triazine framework (CTF) formed by the condensation of N 2,N 4,N 6-tris(4-(aminomethyl)benzyl)-1,3,5-triazine-2,4,6-triamine and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine on which silica is immobilized (TPT-TAT/silica) as an innovative catalyst for porphyrins synthesis. Under solvothermal conditions, the condensation of triamine and trialdehyde precursors led to the formation of a covalent triazine framework (CTF) with a high nitrogen content. The resulting CTF is characterized by its extensive porosity and elevated nitrogen levels, which are critical for the creation of catalytic active sites. This framework demonstrated exceptional catalytic performance in the synthesis of porphyrins. Substituting aerobic conditions in lieu of costly oxidizing agents represents a significant advancement in our methodology. Due to the insolubility of the catalyst, it is possible to separate it from the reaction mixture through filtration or centrifugation. This property enhances its reusability and minimizes waste generation. This development in the synthesis and application of CTFs could pave the way for more sustainable and cost-effective catalytic processes in organic synthesis, particularly in the synthesis of complex molecules like porphyrins. The research highlights the potential of CTFs as versatile materials in catalysis, owing to their structural properties and the ability to tailor their functionalities for specific applications.

Charge Engineering of Star-Shaped Organic Photosensitizers Enables Efficient Type-I Radicals for Photodynamic Therapy of Multidrug-Resistant Bacterial Infection

Infection induced by multidrug-resistant bacteria is now the second most common cause of accidental death worldwide. However, identifying a high-performance strategy with good efficiency and low toxicity is still urgently needed. Antibacterial photodynamic therapy (PDT) is considered a non-invasive and efficient approach with minimal drug resistance. Whereas, the precise molecular design for highly efficient oxygen-independent type-I photosensitizers is still undefined. In this work, the regulation of the positive charge of star-shaped NIR-emissive organic photosensitizers can boost radical generation for the efficient treatment of wounds infected with multidrug-resistant bacteria. With positive charge engineering, TPAT-DNN, which has six positive charges, mainly produces hydroxyl radicals via the type-I pathway, while TPAT-DN, which has three positive charges, tends to generate singlet oxygen and superoxide radicals. For multidrug-resistant bacteria, TPAT-DNN exhibited specific killing effects on multidrug-resistant gram-positive bacteria at low concentrations, while TPAT-DN is similar antibacterial effects on both multidrug-resistant gram-negative and gram-positive bacteria. Furthermore, the efficiency and safety of TPAT-DNN for eradicating multidrug-resistant bacteria methicillin-resistant S. aureus (MRSA) infection and accelerating wound healing in an MRSA-infected mouse model are demonstrated. This work offers a new approach toward manipulating efficient type-I photosensitizers for MRSA treatment.

Photoactivated hydride therapy under hypoxia beyond ROS

As compared to oxidative phototherapy, studies on reactive reductive species-participating photodynamic therapy (PDT) are rare. Porphyrins are typical photosensitizers restricted by the oxygen level, but efficacy and selectivity are always incompatible in PDT. Herein, we report that phlorins are ideal hydride (H-) donors and explore a water-soluble triphenylphosphonium-modified zinc-coordinated porphyrin (mitoZnPor) for in situ photogeneration of zinc-cored phlorin (mitoZnPhl). Driven by 1,4-dihydronicotinamide adenine dinucleotide (NADH), the mitoZnPor/mitoZnPhl couple can reduce electron acceptors like iron heme and ubiquinone that play key roles in the mitochondrial electron transport chain (Mito-ETC). Under hypoxia, mitoZnPor showed excellent cancer-selectivity and a highly efficient in vitro PDT effect with IC50 at nanomolar levels and potent tumor growth inhibition in a 4T1 tumor-xenografted mouse model with good biosafety, which underlines the great potential of Mito-ETC targeted non-classical PDT via a H--transfer mechanism beyond reactive oxygen species (ROS) in precision cancer phototherapy using NADH as a biomarker and original electron donor.

Tetramethyl Cucurbit[6]uril-Porphyrin Supramolecular Polymer Enhances Photosensitization

Porphyrins serve as photosensitizers (PS) in the realm of cancer photodynamic therapy (PDT). Upon excitation by laser light, porphyrins are capable of converting molecular oxygen into highly cytotoxic singlet oxygen (1O2). However, the rigid π-conjugated structure of porphyrins frequently results in the formation of aggregates in aqueous solutions, which leads to the self-quenching of the excited state. Cucurbit[n]urils exhibit the capacity to stably bind with porphyrins via host-guest interactions, effectively inhibiting their aggregation and potentially enhancing the therapeutic efficacy of PDT. In this study, water-soluble tetramethyl cucurbit[6]uril (TMeQ[6]) was selected as the host, while four propionic acid group-appended porphyrin cationic (TPPOR) was utilized as guests to construct a supramolecular photosensitizer (TPPOR-2TMeQ[6]) in a molar ratio of 2:1. Further experimental findings demonstrate that the presence of TMeQ[6] inhibits the aggregation of TPPOR through non-covalent interactions. This inhibition reduces the energy difference between the excited singlet and triplet states, thereby enhancing the conversion efficiency of 1O2. Moreover, TPPOR-2TMeQ[6] exhibits favorable biocompatibility and minimal dark toxicity against breast cancer cells (4T1). Upon intracellular excitation, the levels of reactive oxygen species (ROS) significantly increase, inducing oxidative stress in 4T1 cells and leading to apoptosis. Consequently, the findings of this study suggest that the enhanced photosensitization achieved through this supramolecular approach is likely to promote the anticancer therapeutic effects of PDT, thereby broadening the application prospects of porphyrins within PDT systems.

Porphyrin-Camptothecin (CPT) Grafted Polyoxazoline Amphiphiles for Tumor Photodynamic-Chemotherapy Combination Treatment

Porphyrin-based photosensitizers are extensively utilized in the realm of photodynamic therapy, capitalizing on their advantageous optical, chemical, and electronic properties. Nonetheless, their application is often constrained by their pronounced hydrophobicity. Structures with a high load capacity and excellent biocompatibility are preferred options to circumvent this obstacle. Herein, we constructed a novel porphyrin-camptothecin (CPT) polymer, which is composed of amphiphilic oxazoline segments, and the drug monomers containing disulfide bonds are modified on the hydrophobic chain of polyoxazoline. The polyoxazoline-porphyrin-CPT (OPC) polymer can self-assemble into nanoparticles in the aqueous phase, possesses excellent stability, and generates abundant singlet oxygen (1O2) under laser irradiation. Additionally, the OPC nanoparticles exhibit satisfactory biocompatibility and high light toxicity against 4T1 cells. In the microenvironment of the tumor, drugs were released from the OPC nanoparticles owing to the high concentration of GSH, causing direct damage to the tumor cell, achieving the combination of photo-chemotherapy. The findings of this research indicate that polyoxazoline porphyrin demonstrates adaptability as a nanoplatform for cancer treatment.

Recent progress of porphyrin metal-organic frameworks for combined photodynamic therapy and hypoxia-activated chemotherapy

Nanoscale metal-organic frameworks integrated with porphyrins (Por-nMOFs) have emerged as efficient nanoplatforms for photodynamic therapy (PDT), which relies on the conversion of molecular oxygen into cytotoxic singlet oxygen. However, the hypoxic microenvironment within tumors significantly limits the efficacy of PDT. To address this challenge, researchers have explored various strategies to either alter or exploit the hypoxic conditions in tumors. One such strategy involves leveraging the porous structure of Por-nMOFs to load hypoxia-activated prodrugs (HAPs) like tirapazamine (TPZ), thereby utilizing the tumor's intrinsic hypoxic environment to trigger a chemotherapeutic effect that synergizes with PDT. Advances in nanoscience have enabled the development of porphyrin-based nMOFs capable of simultaneously loading both porphyrin photosensitizers and TPZ, ensuring effective release within cancer cells under high-phosphate conditions. The subsequent activation of co-loaded TPZ, by the tumor's own hypoxic microenvironment, and that created during PDT, facilitates a combined PDT and chemotherapy approach. This method not only enhances the suppression of cancer cell proliferation but also improves control over tumor metastasis while mitigating the negative impact of hypoxia on singular Por-nMOFs in PDT. This review summarizes recent advances in Por-nMOFs research, focusing on the design strategies for enhancing water dispersibility, circulatory stability, and targeting specificity through post-synthetic modifications. Additionally, this review highlights the bioapplication of Por-nMOFs by integrating TPZ chemotherapy and other therapeutic modalities to combat hypoxic and metastatic malignancies. We anticipate that this review will inspire further research into Por-nMOFs and advance their application in biomedicine.

A Combined Phyto- and Photodynamic Delivery Nanoplatform Enhances Antimicrobial Therapy: Design, Preparation, In Vitro Evaluation, and Molecular Docking

Microbial combating is one of the hot research topics, and finding an alternative strategy is considerably required nowadays. Here, we report on a developed combined chemo- and photodynamic delivery system with a core of zinc oxide nanoparticles (ZnO NPs), porphyrin photosensitizer (POR) connected to alginate polymer (ALG), and berberine (alkaloid natural agent, BER) with favorable antimicrobial effects. According to the achieved main designs, the results demonstrated that the loading capacity and entrapment efficiency reached 22.2 wt % and 95.2%, respectively, for ZnO@ALG-POR/BER nanoformulation (second design) compared to 5.88 wt % and 45.1% for ZnOBER@ALG-POR design (first design). Importantly, when the intended nanoformulations were combined with laser irradiation for 10 min, they showed effective antifungal and antibacterial action against Candida albicans, Escherichia coli, and Staphylococcus aureus. Comparing these treatments to ZnO NPs and free BER, a complete (100%) suppression of bacterial and fungal growth was observed by ZnO@ALG-POR/BER nanoformulation treated E. coli, and by ZnOBER treated C. albicans. Also, after laser treatments, most data showed that E. coli was more sensitive to treatments using nanoformulations than S. aureus. The nanoformulations like ZnOBER@ALG-POR were highly comparable to traditional antibiotics against C. albicans and E. coli before laser application. The results of the cytotoxicity assessment demonstrated that the nanoformulations exhibited moderate biocompatibility on normal human immortalized retinal epithelial (RPE1) cells. Notably, the most biocompatible nanoformulation was ZnOBER@ALG-POR, which possessed ∼9% inhibition of RPE1 cells compared to others. High binding affinities were found between all three microbial strains' receptor proteins and ligands in the molecular docking interaction between the receptor proteins and the ligand molecules (mostly BER and POR). In conclusion, our findings point to the possible use of hybrid nanoplatform delivery systems that combine natural agents and photodynamic therapy into a single therapeutic agent, effectively combating microbial infections. Therapeutic efficiency correlates with nanoformulation design and microorganisms, demonstrating possible optimization for further development.

Improving the Photodynamic Activity of Water-Soluble Porphyrin-Polysaccharide Complexes by Folic Acid Modification

Studies have shown that folate receptors are highly expressed in various cancer cells. Here, we synthesized folic acid-conjugated pullulan (FAPL) as a solubilizing agent to improve the photodynamic activity of porphyrin derivative-polysaccharide complexes. The porphyrin derivative-FAPL complex exhibited long-term stability in an aqueous solution, attributed to the folic acid modification. Furthermore, in vitro and in vivo experiments highlighted the enhanced photodynamic activity of the porphyrin derivative-FAPL complex toward 4T1 breast-cancer cells, compared with the activities of the porphyrin derivative-pullulan complex and Photofrin. This enhanced activity is attributed to the improvement of intracellular uptake by the folate receptor.

A Class of Heptaphyrins with NIR Absorption Modulated by Metal Coordination and Nucleophilic Substitution

The intensive interest in expanded porphyrins can be attributed to their appealing photoelectric and coordination behavior. In this work, an N-confused heptaphyrin 1 was synthesized by an acid-catalyzed [3+4] condensation reaction. The introduction of an N-confused pyrrolic unit into the heptaphyrin macrocycle led to the formation of a figure-eight-like conformation with nonsymmetrical "NNNN" and "NNNC" coordination cavities employable for bimetallic coordination. As a result, chelation of 1 with Zn(II) and Cu(II) afforded mono-Zn(II) complex 2 and bis-Cu(II) complex 3, respectively, with the metal atoms exhibiting distorted square-planar geometries. In complex 3, an oxygen atom is attached to the α-C atom of N-confused pyrrole D, and thus the N and C atoms of ring D participate in coordination within the two cavities. Interestingly, treatment of 1 with Cs2CO3 in MeOH resulted in regioselective substitution of all the seven para-F atoms in the meso-C6F5 groups as well as the α-H of ring D by eight methoxy moieties. Complex 3 displays a red-shifted absorption band edge of ca. 2200 nm, compared to that of ca. 1600 nm observed for 1. This work provides an example of incorporating an N-confused pyrrole to construct expanded porphyrins with distinctive coordination behavior and tunable NIR absorption.

A GSH-Responsive Prodrug with Simultaneous Triple-Activation Capacity for Photodynamic/Sonodynamic Combination Therapy with Inhibited Skin Phototoxicity

Herein, a dual-sensitizer prodrug, named pro-THPC, has been designed to function as both a photosensitizer and a sonosensitizer prodrug for precise antitumor combination therapy with minimized skin phototoxicity. Pro-THPC could be activated by glutathione (GSH) to release the dual-sensitizer, THPC, which simultaneously switches on fluorescence emission and combined capabilities of photodynamic therapy (PDT) and sonodynamic therapy (SDT). Pro-THPC is further formulated into nanoparticles (NPs) for water dispersity to enable in vivo applications. In vivo fluorescence imaging shows that the pro-THPC NPs group exhibits a significantly higher tumor-to-normal tissue ratio (T/N) (T/N = 5.2 ± 0.55) compared to the "always on" THPC NPs group (T/N = 2.9 ± 0.47) and the pro-THPC NPs group co-administrated with GSH synthesis inhibitor (buthionine sulfoximine, BSO) (T/N = 3.2 ± 0.63). In addition, the generation of the designed dual-sensitizer's reactive oxygen species (ROS) is effectively confined within the tumor tissues due to the relatively strong correlation between ROS generation and fluorescence emission. In vivo studies further demonstrate the remarkable efficacy of the designed pro-THPC NPs to eradicate tumors through the combination of PDT and SDT while significantly reducing skin phototoxicity.

meso-5,15-Bis[3-(iso-propyl-idenegalacto-pyran-oxy)phen-yl]-10,20-bis-(4-methyl-phen-yl)porphyrin

The crystal structure of a glycosyl-ated porphyrin (P_Gal2) system, C70H70N4O12, where two iso-propyl-idene protected galactose moieties are attached to the meso position of a substituted tetra-aryl porphyrin is reported. This structure reveals that the parent porphyrin is planar, with the galactose moieties positioned above and below the porphyrin macrocycle. This orientation likely prevents porphyrin-porphyrin H-type aggregation, potentially enhancing its efficiency as a photosensitizer in photodynamic therapy. Notable non-bonding C-H⋯O and C-H⋯π inter-actions among adjacent P_Gal2 systems are observed in this crystal network. Additionally, the tolyl groups of each porphyrin can engage in π-π inter-actions with the delocalized π-systems of neighboring porphyrins.

Biomimetic Gold Nanorods-Manganese Porphyrins with Surface-Enhanced Raman Scattering Effect for Photoacoustic Imaging-Guided Photothermal/Photodynamic Therapy

Surface-enhanced Raman scattering (SERS) imaging integrating photothermal and photodynamic therapy (PTT/PDT) is a promising approach for achieving accurate diagnosis and effective treatment of cancers. However, most available Raman reporters show multiple signals in the fingerprint region, which overlap with background signals from cellular biomolecules. Herein, a 4T1 cell membrane-enveloped gold nanorods-manganese porphyrins system (GMCMs) is designed and successfully fabricated as a biomimetic theranostic nanoplatform. Manganese porphyrins are adsorbed on the surface of Au nanorods via the terminal alkynyl group. Cell membrane encapsulation protects the manganese porphyrins from falling off the gold nanorods. The biomimetic GMCMs confirm specific homologous targeting to 4T1 cells with good dispersibility, excellent photoacoustic (PA) imaging properties, and preferable photothermal and 1O2 generation performance. GMCMs exhibit distinct SERS signals in the silent region without endogenous biomolecule interference both in vitro and in vivo. Manganese ions could not only quench the fluorescence of porphyrins to enhance the SERS imaging effect but also deplete cellular GSH to increase 1O2 yield. Both in vitro and in vivo studies demonstrate that GMCMs effectively eradicate tumors through SERS/PA imaging-guided PTT/PDT. This study provides a feasible strategy for augmenting the Raman imaging effects of the alkynyl group and integrating GSH-depletion to enhance PTT/PDT efficacy.

Advancements of Porphyrin-Derived Nanomaterials for Antibacterial Photodynamic Therapy and Biofilm Eradication

The threat posed by antibiotic-resistant bacteria and the challenge of biofilm formation has highlighted the inadequacies of conventional antibacterial therapies, leading to increased interest in antibacterial photodynamic therapy (aPDT) in recent years. This approach offers advantages such as minimal invasiveness, low systemic toxicity, and notable effectiveness against drug-resistant bacterial strains. Porphyrins and their derivatives, known for their high molar extinction coefficients and singlet oxygen quantum yields, have emerged as crucial photosensitizers in aPDT. However, their practical application is hindered by challenges such as poor water solubility and aggregation-induced quenching. To address these limitations, extensive research has focused on the development of porphyrin-based nanomaterials for aPDT, enhancing the efficacy of photodynamic sterilization and broadening the range of antimicrobial activity. This review provides an overview of various porphyrin-based nanomaterials utilized in aPDT and biofilm eradication in recent years, including porphyrin-loaded inorganic nanoparticles, porphyrin-based polymer assemblies, supramolecular assemblies, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). Additionally, insights into the prospects of aPDT is offered, highlighting its potential for practical implementation.

Synthesis, Structural, Electrochemical, and DFT Studies of Highly Substituted Nonplanar Ni(II) Porphyrins and Their Intensity-Dependent Third-Order Nonlinear Optical Properties

We designed and successfully synthesized highly substituted electron-deficient nonplanar Ni(II) porphyrins and their derivatives (1-7) in moderate to good yields. These derivatives were comprehensively characterized by various spectroscopic techniques and single-crystal X-ray diffraction (SCXRD) analysis. SCXRD analysis confirmed the structures of compounds 2, 4, and 7, adopting saddle-shape geometry. These nonplanar porphyrins demonstrated significant bathochromic shifts in their absorption spectra compared to parent NiTPP, attributed to the influence of bulky β-substituents and/or peripheral fusion. π-Extended porphyrins 6 and 7 displayed panchromatic absorption spectra extending into the NIR region. Porphyrins 6 and 7 demonstrated a profound anodic shift (∼400 mV) in their first reduction peak potentials compared to precursor NiTPP(NO2)Br6. The experimental absorption spectral pattern matches the simulated absorption spectra obtained from TD-DFT studies. The femtosecond laser intensity-dependent third-order nonlinear optical studies revealed that NiDFP(VCN)2Br6 (6) and NiDFP(VCN)2(PE)6 (7) displayed giant optical nonlinearities compared to the other porphyrins. Among all, NiDFP(VCN)2Br6 (6) possessed the highest two-photon absorption coefficient (β) and cross-section (σTPA) values in the range of 22-33 × 10-10 m/W and 3.77-6.95 × 106 GM, respectively. These findings suggest that the investigated nonplanar π-extended porphyrins are promising candidates for future optoelectronic applications.

Intramolecular Charge Transfer and Spin-Orbit Coupled Intersystem Crossing in Hypervalent Phosphorus(V) and Antimony(V) Porphyrin Black Dyes

Porphyrin dyes with strong push-pull type intramolecular charge transfer (ICT) character and broad absorption across the visible spectrum are reported. This combination of properties has been achieved by functionalizing the periphery of hypervalent and highly electron-deficient phosphorus(V) and antimony(V) centered porphyrins with electron-rich triphenylamine (TPA) groups. As a result of the large difference in electronegativity between the porphyrin ring and the peripheral groups, their absorption profiles show several strong charge transfer transitions, which in addition to the porphyrin-centered π → π* transitions, make them panchromatic black dyes with high absorption coefficients between 200 and 800 nm. Time-resolved optical and electron paramagnetic resonance (EPR) studies show that the lowest triplet state also has ICT character and is populated by spin-orbit coupled intersystem crossing.

Micelles of poly[oligo(ethylene glycol) methacrylate] as delivery vehicles for zinc phthalocyanine photosensitizers

Drug-loaded polymeric micelles have proven to be highly effective carrier systems for the efficient delivery of hydrophobic photosensitizers (PSs) in photodynamic therapy (PDT). This study introduces the micellization potential of poly(oligoethylene glycol methyl ether methacrylate) (pOEGMA) as a novel approach, utilizing the hydrophobic methacrylate segments of pOEGMA to interact with highly hydrophobic zinc phthalocyanine (ZnPc), thereby forming a potential micellar drug carrier system. The ZnPc molecule was synthesized from phthalonitrile derivatives and its fluorescence, photodegradation, and singlet oxygen quantum yields were determined in various solvents. In solvents such as tetrahydrofuran, dimethyl sulfoxide, and N,N-dimethylformamide, the ZnPc compound exhibited the requisite photophysical and photochemical properties for PDT applications. The pOEGMA homopolymer was synthesized via reversible addition-fragmentation chain-transfer polymerization, while ZnPc-loaded pOEGMA micelles were prepared using the nanoprecipitation method. Characterization of the pOEGMA, ZnPc, and micelles was conducted using FTIR,1H-NMR, dynamic light scattering, matrix-assisted laser desorption/ionization time-of-flight mass spectrometries, gel permeation chromatography, and transmission electron microscopy. The critical micelle concentration was determined to be 0.027 mg ml-1using fluorescence spectrometry. The drug loading and encapsulation efficiencies of the ZnPc-loaded micelles were calculated to be 0.67% and 0.47%, respectively. Additionally, the release performance of ZnPc from pOEGMA micelles was monitored over a period of nearly 10 d, while the lyophilized micelles exhibited stability for 3 months. Lastly, the ZnPc-loaded micelles were more biocompatible than ZnPc on L929 cell line. The results suggest that the pOEGMA homopolymer possesses the capability to micellize through its methacrylate segments when interacting with highly hydrophobic molecules, presenting a promising avenue for enhancing the delivery efficiency of hydrophobic PSs in PDT. Moreover, it was also deciphered that obtained formulations were highly biocompatible according to cytotoxicity results and could be safely employed as drug delivery systems in further applications.

Metal-polyphenol self-assembled nanodots for NIR-II fluorescence imaging-guided chemodynamic/photodynamic therapy-amplified ferroptosis

The effectiveness of tumor treatment using reactive oxygen species as the primary therapeutic medium is hindered by limitations of tumor microenvironment (TME), such as intrinsic hypoxia in photodynamic therapy (PDT) and overproduction of reducing glutathione (GSH) in chemodynamic therapy (CDT). Herein, we fabricate metal-polyphenol self-assembled nanodots (Fe@BDP NDs) guided by second near-infrared (NIR-II) fluorescence imaging. The Fe@BDP NDs are designed for synergistic combination of type-I PDT and CDT-amplified ferroptosis. In a mildly acidic TME, Fe@BDP NDs demonstrate great Fenton activity, leading to the generation of highly toxic hydroxyl radicals from overproduced hydrogen peroxide in tumor cells. Furthermore, Fe@BDP NDs show favorable efficacy in type-I PDT, even in tolerating tumor hypoxia, generating active superoxide anion upon exposure to 808 nm laser irradiation. The significant efficiency in reactive oxygen species (ROS) products results in the oxidation of sensitive polyunsaturated fatty acids, accelerating lethal lipid peroxidation (LPO) bioprocess. Additionally, Fe@BDP NDs illustrate an outstanding capability for GSH depletion, causing the inactivation of glutathione peroxidase 4 and further promoting lethal LPO. The synergistic type-I photodynamic and chemodynamic cytotoxicity effectively trigger irreversible ferroptosis by disrupting the intracellular redox homeostasis. Moreover, Fe@BDP NDs demonstrate charming NIR-II fluorescence imaging capability and effectively accumulated at the tumor site, visualizing the distribution of Fe@BDP NDs and the treatment process. The chemo/photo-dynamic-amplified ferroptotic efficacy of Fe@BDP NDs was evidenced both in vitro and in vivo. This study presents a compelling approach to intensify ferroptosis via visualized CDT and PDT. STATEMENT OF SIGNIFICANCE: In this study, we detailed the fabrication of metal-polyphenol self-assembled nanodots (Fe@BDP NDs) guided by second near-infrared (NIR-II) fluorescence imaging, aiming to intensify ferroptosis via the synergistic combination of type-I PDT and CDT. In a mildly acidic TME, Fe@BDP NDs exhibited significant Fenton activity, resulting in the generation of highly toxic •OH from overproduced H2O2 in tumor cells. Fe@BDP NDs possessed a remarkable capability for GSH depletion, resulting in the inactivation of glutathione peroxidase 4 (GPX4) and further accelerating lethal LPO. This study presented a compelling approach to intensify ferroptosis via visualized CDT and PDT.

Structural Decoration of Porphyrin/Phthalocyanine Photovoltaic Materials

Porphyrin/phthalocyanine compounds with fascinating molecular structures have attracted widespread attention in the field of solar cells in recent years. In this review, we focus on the pivotal role of porphyrin and phthalocyanine compounds in enhancing the efficiency of solar cells. The review seamlessly integrates the intricate molecular structures of porphyrins and phthalocyanines with their proficiency in absorbing visible light and facilitating electron transfer, key processes in converting sunlight into electricity. By delving into the nuances of intramolecular regulation, aggregated states, and surface/interface structure manipulation, it elucidates how various levels of molecular modifications enhance solar cell efficiency through improved charge transfer, stability, and overall performance. This comprehensive exploration provides a detailed understanding of the complex relationship between molecular design and solar cell performance, discussing current advancements and potential future applications of these molecules in solar energy technology.

Recent advances for enhanced photodynamic therapy: from new mechanisms to innovative strategies

Photodynamic therapy (PDT) has been developed as a potential cancer treatment approach owing to its non-invasiveness, spatiotemporal control and limited side effects. Currently, great efforts have been made to improve the PDT effect in terms of safety and efficiency. In this review, we highlight recent advances in innovative strategies for enhanced PDT, including (1) the development of novel radicals, (2) design of activatable photosensitizers based on the TME and light, and (3) photocatalytic NADH oxidation to damage the mitochondrial electron transport chain. Additionally, the new mechanisms for PDT are also presented as an inspiration for the design of novel PSs. Finally, we discuss the current challenges and future prospects in the clinical practice of these innovative strategies. It is hoped that this review will provide a new angle for understanding the relationship between the intratumoural redox environment and PDT mechanisms, and new ideas for the future development of smart PDT systems.

Charge-reversal polymeric nanomodulators for ferroptosis-enhanced photodynamic therapy

The clinical application of photodynamic therapy (PDT) has some limitations including poor tumor targeting properties, a high reductive tumor microenvironment, and inefficient activation of single cell death machinery. We herein report pH-sensitive polymeric nanomodulators (NBS-PDMC NPs) for ferroptosis-enhanced photodynamic therapy. NBS-PDMC NPs were constructed using a positively charged type-I photosensitizer (NBS) coordinated with a demethylcantharidin (DMC)-decorated block copolymer via electrostatic interactions. NBS-PDMC NPs had a negative surface charge, which ensures their high stability in bloodstream circulation, while exposure to lysosomal acidic environments reverses their surface charge to positive for tumor penetration and the release of DMC and NBS. Under NIR light irradiation, NBS generated ROS to induce cell damage; in the meantime, DMC inhibited the expression of the GPX4 protein in tumor cells and promoted ferroptosis of tumor cells. This polymer design concept provides some novel insights into smart drug delivery and combinational action to amplify the antitumor effect.

Small molecule-engineered nanoassembly for lipid peroxidation-amplified photodynamic therapy

Photodynamic therapy (PDT), extensively explored as a non-invasive and spatio-temporal therapeutic modality for cancer treatment, encounters challenges related to the brief half-life and limited diffusion range of singlet oxygen. Lipid peroxides, formed through the oxidation of polyunsaturated fatty acids by singlet oxygen, exhibit prolonged half-life and potent cytotoxicity. Herein, we employed small molecule co-assembly technology to create nanoassemblies of pyropheophorbide a (PPa) and docosahexaenoic acid (DHA) to bolster PDT. DHA, an essential polyunsaturated fatty acid, co-assembled with PPa to generate nanoparticles (PPa@DHA NPs) without the need for additional excipients. To enhance the stability of these nanoassemblies, we introduced 20% DSPE-PEG2k as a stabilizing agent, leading to the formation of PPa@DHA PEG2k NPs. Upon laser irradiation, PPa-produced singlet oxygen swiftly oxidized DHA, resulting in the generation of cytotoxic lipid peroxides. This process significantly augmented the therapeutic efficiency of PDT. Consequently, tumor growth was markedly suppressed, attributed to the sensitizing and amplifying impact of DHA on PDT in a 4T1 tumor-bearing mouse model. In summary, this molecule-engineered nanoassembly introduces an innovative co-delivery approach to enhance PDT with polyunsaturated fatty acids.

Metal organic framework-based variable-size nanoparticles for tumor microenvironment-responsive drug delivery

Nanoparticles (NPs) have been designed for the treatment of tumors increasingly. However, the drawbacks of single-size NPs are still worth noting, as their circulation and metabolism in the blood are negatively correlated with their accumulation at the tumor site. If the size of single-size NPs is too small, it will be quickly cleared in the blood circulation, while, the size is too large, the distribution of NPs in the tumor site will be reduced, and the widespread distribution of NPs throughout the body will cause systemic toxicity. Therefore, a class of variable-size NPs with metal organic frameworks (MOFs) as the main carrier, and size conversion in compliance with the characteristics of the tumor microenvironment (TME), was designed. MOF-based variable-size NPs can simultaneously extend the time of blood circulation and metabolism, then enhance the targeting ability of the tumor site. In this review, MOF NPs are categorized and exemplified from a new perspective of NP size variation; the advantages, mechanisms, and significance of MOF-based variable-size NPs were summarized, and the potential and challenges in delivering anti-tumor drugs and multimodal combination therapy were discussed.

Porphyrin-based porous organic polymers synthesized using the Alder-Longo method: the most traditional synthetic strategy with exceptional capacity

Porphyrin is a typical tetrapyrrole chromophore-based pigment with a special electronic structure and functionalities, which is frequently introduced into various porous organic polymers (POPs). Porphyrin-based POPs are widely used in various fields ranging from environmental and energy to biomedicine-related fields. Currently, most porphyrin-based POPs are prepared via the copolymerization of specific-group-functionalized porphyrins with other building blocks, in which the tedious and inefficient synthesis procedure for the porphyrin greatly hinders the development of such materials. This review aimed to summarize information on porphyrin-based POPs synthesized using the Alder-Longo method, thereby skipping the complex synthesis of porphyrin-bearing monomers, in which the porphyrin macrocycles are formed directly via the cyclic tetramerization of pyrrole with monomers containing multiple aldehyde groups during the polymerization process. The representative applications of porphyrin-based POPs derived using the Alder-Longo method are finally introduced, which pinpoints a clear relationship between the structure and function from the aspect of the building blocks used and porous structures. This review is therefore valuable for the rational design of efficient porphyrin-based porous organic polymer systems that may be utilized in various fields from energy-related conversion/storage technologies to biomedical science.

Metal-Organic Framework PCN-224 Combined Cobalt Oxide Nanoparticles for Hypoxia Relief and Synergistic Photodynamic/Chemodynamic Therapy

Photodynamic therapy (PDT) and chemodynamic therapy (CDT) are promising tumor treatments mediated by reactive oxygen species (ROS), which have the advantages of being minimally invasive. However, the hypoxia of tumor microenvironment and poor target ability often reduce the therapeutic effect. Here we propose a tumor targeted nanoplatform PCN-224@Co3O4-HA for enhanced PDT and synergistic CDT, constructed by hyaluronate-modified Co3O4 nanoparticles decorated metal-organic framework PCN-224. Co3O4 can catalyze the decomposition of highly expressed H2O2 in tumor cells to produce oxygen and alleviate the problem of hypoxia. It can also produce hydroxyl radicals according to the Fenton-like reaction for chemical dynamic therapy, significantly improving the therapeutic effect. The cell survival experiment showed that after in vitro treatment, 4T1 and MCF-7 cancer cells died in a large area under the anaerobic state, while the survival ability of normal cell L02 was nearly unchanged. This result effectively indicated that PCN-224@Co3O4-HA could effectively relieve tumor hypoxia and improve the effect of PDT and synergistic CDT. Cell uptake experiments showed that PCN-224@Co3O4-HA had good targeting properties and could effectively aggregate in tumor cells. In vivo experiments on mice, PCN-224@Co3O4-HA presented reliable biosafety performance, and can cooperate with PDT and CDT therapy to prevent the growth of tumor.

TME-Triggered Degradable Phototheranostic Nanoplatform for NIR-II Fluorescence Bioimaging-Guided Phototherapies and Immune Activation

The low therapeutic efficacy and potential long-term toxicity of antitumor treatments seriously limit the clinical application of phototherapies. Herein, we develop a degradable phototheranostic nanoplatform for NIR-II fluorescence bioimaging-guided synergistic photothermal (PTT) and photodynamic therapies (PDT) and immune activation to inhibit tumor growth. The phototheranostic nanoplatform (CX@PSS) consists of multidisulfide-containing polyurethane loaded with a photosensitizer CX, which can be specifically degraded in the GSH overexpressed tumor microenvironment (TME) and exhibits good NIR-II fluorescence, photodynamic, and photothermal properties. Under 808 nm light irradiation, CX@PSS exhibits efficient photothermal conversion and ROS generation, which further induces immunogenic cell death (ICD), releasing tumor-associated antigens and activating the immune response. In vitro and in vivo studies confirm the potential of CX@PSS in NIR II FL imaging-guided tumor treatments by synergistic PTT, PDT, and immune activation. This work is expected to provide a new pathway for clinical applications of imaging-guided tumor diagnosis and treatments.

Ambient Synthesis of Porphyrin-Based Fe-Covalent Organic Frameworks for Efficient Infected Skin Wound Healing

Reactive oxygen species (ROS) have emerged as a promising treatment option for antibacterial and biofilm eradication. However, their therapeutic efficacy is significantly hampered by the unique microenvironments of diabetic wounds. In this study, we designed and synthesized porphyrin-based Fe covalent organic frameworks (Fe-COF) through a Schiff base condensation reaction. Subsequently, Fe-COF were encapsulated with hyaluronic acid (HA) through electrostatic adsorption, resulting in a novel formulation named HA-Fe-COF for diabetic wound healing. HA-Fe-COF were engineered to respond to hyaluronidase in the infected wound, leading to the controlled release of Fe-COF. Those released Fe-COF served a dual role as photosensitizers, generating singlet oxygen and localized heating when exposed to dual light sources. Additionally, they acted as peroxidase-like nanozymes, facilitating the production of ROS through enzymatic reactions. This innovative approach enabled a synergistic therapeutic effect combining photodynamic, photothermal, and chemodynamic modalities. Furthermore, the sustained release of HA from HA-Fe-COF promoted angiogenesis, collagen deposition, and re-epithelialization during the diabetic wound healing process. This "all-in-one" strategy offers a novel approach for the development of antimicrobial and biofilm eradication strategies that minimize damage to healthy tissues in vivo.

Why does the orientation of azulene affect the two-photon activity of a porphyrinoid-azulene system?

Attaching a dipolar molecule in a symmetric system induces a major change in the electronic structure, which may be reflected as the enhancement of the optical and charge-transfer properties of the combined system as compared to the pristine ones. Furthermore, the orientation of the dipolar molecule may also affect the said properties. This idea is explored in this work by taking porphyrinoid molecules as the pristine systems. We attached azulene, a dipolar molecule, at various positions of five porphyrinoid cores and studied the effect on charge-transfer and one- and two-photon absorption properties using the state-of-the-art RICC2 method. The attachment of azulene produces two major effects - firstly it introduces asymmetry in the system and, secondly, being dipolar, it makes the resultant molecule dipolar/quadrupolar. Porphyrin, N-confused porphyrin, sub-porphyrin, sapphyrin, and hexaphyrin are used as core porphyrinoid systems. The change in charge-transfer has been studied using the orbital analysis and charge-transfer distance parameter for the first five singlet states of the systems. The effect of orientation of azulene on the said properties is also explored. The insights gained from our observations are explored further at the dipole and transition dipole moment levels using a three-state model.

Porphyrin-Based Self-Assembled Nanoparticles for PET/MR Imaging of Sentinel Lymph Node Metastasis

Diagnosing of lymph node metastasis is challenging sometimes, and multimodal imaging offers a promising method to improve the accuracy. This work developed porphyrin-based nanoparticles (68Ga-F127-TAPP/TCPP(Mn) NPs) as PET/MR dual-modal probes for lymph node metastasis imaging by a simple self-assembly method. Compared with F127-TCPP(Mn) NPs, F127-TAPP/TCPP(Mn) NPs synthesized by amino-porphyrins (TAPP) doping can not only construct PET/MR bimodal probes but also improve the T1 relaxivity (up to 456%). Moreover, T1 relaxivity can be adjusted by altering the molar ratio of TAPP/TCPP(Mn) and the concentration of F127. However, a similar increase in T1 relaxivity was not observed in the F127-TCPP/TCPP(Mn) NPs, which were synthesized using carboxy-porphyrins (TCPP) doping. In a breast cancer lymph node metastasis mice model, subcutaneous injection of 68Ga-F127-TAPP/TCPP(Mn) NPs through the hind foot pad, the normal lymph nodes and metastatic lymph nodes were successfully distinguished based on the difference of PET standard uptake values and MR signal intensities. Furthermore, the dark brown F127-TAPP/TCPP(Mn) NPs demonstrated the potential for staining and mapping lymph nodes. This study provides valuable insights into developing and applying PET/MR probes for lymph node metastasis imaging.

An ambipolar PEDOT-perfluorinated porphyrin electropolymer: application as an active material in energy storage systems

The development of functional organic materials is crucial for the advancement of various fields, such as optoelectronics, energy storage, sensing, and biomedicine. In this context, we successfully prepared a stable ambipolar perfluoroporphyrin-based polymeric film by electrochemical synthesis. Our strategy involved the synthesis of a novel tetra-pentafluorophenyl porphyrin covalently linked to four 3,4-ethylenedioxythiophene (EDOT) moieties. The resulting monomer, EDOT-TPPF16, was obtained through a straightforward synthetic approach with a good overall yield. The unique molecular structure of EDOT-TPPF16 serves a dual function, with EDOT moieties allowing electropolymerization for polymeric film formation, while the electron-acceptor porphyrin core enables electrochemical reduction and electron transport. The electrochemical polymerization permits the polymer (PEDOT-TPPF16) synthesis and film formation in a reproducible and controllable manner in one step at room temperature. Spectroelectrochemical experiments confirmed that the porphyrin retained its optoelectronic properties within the polymeric matrix after the electrochemical polymerization. The obtained polymeric material exhibited stable redox capabilities. Current charge-discharge cycles and electrochemical impedance spectroscopy of the electrochemically generated organic film demonstrated that the polymer could be applied as a promising active material in the development of supercapacitor energy storage devices.

Tumor targeted porphyrin-based metal-organic framework for photodynamic and checkpoint blockade immunotherapy

Photodynamic therapy (PDT) has become a promising approach and non-invasive modality for cancer treatment, however the therapeutic effect of PDT is limited in tumor metastasis and local recurrence. Herein, a tumor targeted nanomedicine (designated as PCN@HA) is constructed for enhanced PDT against tumors. By modified with hyaluronic acid (HA), which could target the CD44 receptor that expressed on the cancer cells, the targeting ability of PCN@HA has been enhanced. Under light irradiation, PCN@HA can produce cytotoxic singlet oxygen (1O2) and kill cancer cells, then eliminate tumors. Furthermore, PCN@HA exhibits fluorescence (FL)/ photoacoustic (PA) effects for multimodal imaging-guided cancer treatment. And PCN@HA-mediated PDT also can induce immunogenic cell death (ICD) and stimulate adaptive immune responses by releasing of tumor antigens. By combining with anti-PD-L1 checkpoint blockade therapy, it can not only effectively suppress the growth of primary tumor, but also inhibit the metastatic tumor growth.

Charge Conversional Biomimetic Nanosystem for Synergistic Photodynamic/Protein Therapy

Cytochrome C (Cytc) has received considerable attention due to its ability to induce tumor apoptosis and generate oxygen to improve photodynamic therapy (PDT) efficiency. However, the damage to normal tissues caused by nonspecific accumulation of Cytc limits its application. Herein, in order to reduce its toxicity to normal tissues while retaining its activity, a charge conversional biomimetic nanosystem (CA/Ce6@MSN-4T1) is proposed to improve the tumor targeting ability and realize controlled release of Cytc in the tumor microenvironment. This nanosystem is constructed by coating tumor cell membrane on mesoporous silica nanoparticles coloaded with a photosensitizer (chlorin e6, Ce6) and the citraconic anhydride conjugated Cytc (CA) for synergistic photodynamic/protein therapy. The coating of the tumor cell membrane endows the nanoparticles with homologous targeting ability to the same cancer cells as well as immune escaping capability. CA undergoes charge conversion in the acidic environment of the tumor to achieve a controlled release of Cytc. The released Cytc can relieve cellular hypoxia to improve the PDT efficiency of Ce6 and can induce programmed cell death. Both in vitro and in vivo studies demonstrated that CA/Ce6@MSN-4T1 can efficiently inhibit the growth of tumors through synergistic photodynamic/protein therapy, and meanwhile show reduced side effects on normal tissues.

Panchromatic Light-Harvesting Three-Dimensional Metal Covalent Organic Frameworks for Boosting Photocatalysis

Constructing artificial photocatalysts with panchromatic solar energy utilization remains an appealing challenge. Herein, two complementary photosensitizers, [Ru(bpy)3]2+ (bpy = 2,2'-bipyridine) and porphyrin dyes, have been cosensitized in metal covalent organic frameworks (MCOFs), resulting in the MCOFs with strong light absorption covering the full visible spectrum. Under panchromatic light irradiation, the cosensitized MCOFs exhibited remarkable photocatalytic H2 evolution with an optimum rate of up to 33.02 mmol g-1 h-1. Even when exposed to deep-red light (λ = 700 ± 10 nm), a commendable H2 production (0.79 mmol g-1 h-1) was still obtained. Theoretical calculation demonstrated that the [Ru(bpy)3]2+ and porphyrin modules in our MCOFs have a synergistic effect to trigger an interesting dual-channel photosensitization pathway for efficient light-harvesting and energy conversion. This work highlights the potential of combining multiple PSs in MCOFs for panchromatic photocatalysis.

Pathogen-Activated Macrophage Membrane Encapsulated CeO2-TCPP Nanozyme with Targeted and Photo-Enhanced Antibacterial Therapy

Nanozymes with peroxidase-mimic activity have recently emerged as effective strategies for eliminating infections. However, challenges in enhancing catalytic activities and the ability to target bacteria have hindered the broader application of nanozymes in bacterial infections. Herein, a novel nanozyme based on mesoporous CeO2 nanosphere and meso-tetra(4-carboxyphenyl)porphine (TCPP) encapsulated within pathogen-activated macrophage membranes, demonstrates photodynamic capability coupled with photo-enhanced chemodynamic therapy for selective and efficient antibacterial application against infected wounds. Interestingly, the expression of Toll-like receptors accordingly upregulates when macrophages are co-cultured with specific bacteria, thereby facilitating to recognition of the pathogen-associated molecular patterns originating from bacteria. The CeO2 not only serve as carriers for TCPP, but also exhibit intrinsic peroxidase-like catalytic activity. Consequently, Staphylococcus aureus (S. aureus)-activated macrophage membrane-coated CeO2-TCPP (S-MM@CeO2-TCPP) generated singlet oxygen, and simultaneously promoted photo-enhanced chemodynamic therapy, significantly boosting reactive oxygen species (ROS) to effectively eliminate bacteria. S-MM@CeO2-TCPP specifically targeted S. aureus via Toll-like receptor, thereby directly disrupting bacterial structural integrity to eradicate S. aureus in vitro and relieve bacteria-induced inflammation to accelerate infected wound healing in vivo. By selectively targeting specific bacteria and effectively killing pathogens, such strategy provides a more efficient and reliable alternative for precise elimination of pathogens and inflammation alleviation in microorganism-infected wounds.

Natural-product-based, carrier-free, noncovalent nanoparticles for tumor chemo-photodynamic combination therapy

Cancer, with its diversity, heterogeneity, and complexity, is a significant contributor to global morbidity, disability, and mortality, highlighting the necessity for transformative treatment approaches. Photodynamic therapy (PDT) has aroused continuous interest as a viable alternative to conventional cancer treatments that encounter drug resistance. Nanotechnology has brought new advances in medicine and has shown great potential in drug delivery and cancer treatment. For precise and efficient therapeutic utilization of such a tumor therapeutic approach with high spatiotemporal selectivity and minimal invasiveness, the carrier-free noncovalent nanoparticles (NPs) based on chemo-photodynamic combination therapy is essential. Utilizing natural products as the foundation for nanodrug development offers unparalleled advantages, including exceptional pharmacological activity, easy functionalization/modification, and well biocompatibility. The natural-product-based, carrier-free, noncovalent NPs revealed excellent synergistic anticancer activity in comparison with free photosensitizers and free bioactive natural products, representing an alternative and favorable combination therapeutic avenue to improve therapeutic efficacy. Herein, a comprehensive summary of current strategies and representative application examples of carrier-free noncovalent NPs in the past decade based on natural products (such as paclitaxel, 10-hydroxycamptothecin, doxorubicin, etoposide, combretastatin A4, epigallocatechin gallate, and curcumin) for tumor chemo-photodynamic combination therapy. We highlight the insightful design and synthesis of the smart carrier-free NPs that aim to enhance PDT efficacy. Meanwhile, we discuss the future challenges and potential opportunities associated with these NPs to provide new enlightenment, spur innovative ideas, and facilitate PDT-mediated clinical transformation.

Self-Illuminating In Situ Hydrogel with Immune-Adjuvant Amplify Cerenkov Radiation-Induced Photodynamic Therapy

Cerenkov radiation-induced photodynamic therapy (CR-induced PDT) has shown the potential to overcome the light penetration limitation in conventional PDT. In addition, the tumor-associated antigens (TAAs) produced by PDT can initiate an antitumor immune process but only show a limited immunotherapeutic effect without the use of immunotherapeutic agents. Herein, a CR-induced PDT hydrogel (R837/89Zr-HG-PpIX) has been developed by in situ formation of a hyaluronic acid (HA)-based hydrogel integrated with internal light source 89Zr, photosensitizer protoporphyrin IX (PpIX), and immune adjuvant imiquimod (R837). The obtained R837/89Zr-HG-PpIX hydrogel with long-term tumor retention and low radiation leakage can provide long-lasting photodynamic therapy without phototoxicity in normal tissues. In addition, the loaded R837 improves the immunogenicity of TAAs released after PDT, resulting in considerably enhanced immune responses. At relatively low radioactivity, R837/89Zr-HG-PpIX shows significant inhibition in subcutaneous H22 tumor-bearing BALB/c mice and orthotopic VX2 liver tumor-bearing rabbits. Furthermore, the combination of such a CR-induced PDT hydrogel with anti-PD-L1 exhibits the abscopal effect to inhibit the growth of distant tumors. Therefore, the proposed in situ formed CR-induced PDT hydrogel with long-term photodynamic-immunotherapy provides an effective strategy for deep tumor therapy.

Novel electrochemical sensing strategy for ultrasensitive detection of tetracycline based on porphyrin/metal phthalocyanine-covalent organic framework

In this work, a novel two-dimensional semiconducting metal covalent organic framework (CuTAPc-TFPP-COF) was synthesized and used as biosensing platform to construct aptasensor for trace detection of tetracycline (TC). The CuTAPc-TFPP-COF integrates the highly conjugated structure, large specific surface area, high porosity, abundant nitrogen functional groups, excellent electrochemical activity, and strong bioaffinity for aptamers, providing abundant active sites to effectively anchor aptamer strands. As a result, the CuTAPc-TFPP-COF-based aptasensor shows high sensitivity for detecting TC via specific recognition between aptamer and TC to form Apt-TC complex. An ultralow detection limit of 59.6 fM is deduced from the electrochemical impedance spectroscopy within a wide linear range of 0.1-100000 pM for TC. The CuTAPc-TFPP-COF-based aptasensor also exhibits good selectivity, reproducibility, stability, regenerability, and excellent applicability for real river water, milk, and pork samples. Therefore, the CuTAPc-TFPP-COF-based aptasensor will be promising for detecting trace harmful antibiotics residues in environmental water and food samples.