Clinical development of photodynamic agents and therapeutic applications

Enhanced fluorescence emission or singlet oxygen production of cationic porphyrazines and porphyrins through combination with carbon dots

A cationic porphyrin and porphyrazine with the 3-ethylpyridyl substituent (H2P and H2Pz) and their respective zinc complexes (ZnP and ZnPz) were assembled to a carbon dot (CD) synthesized from citric acid and ammonium citrate. A titration was performed using a fluorescence spectrophotometer to determine the stoichiometric ratio at which the maximum interaction between the substances occurs, as well as the Stern-Volmer constant and intrinsic binding constant. The combination between CD and porphyrins or porphyrazines was confirmed using UV-VIS absorption spectroscopy, fluorescence emission, zeta potential, and Diffusion-Ordered NMR Spectroscopy (DOSY). It was observed that after combination, there is a decline in the absorption of porphyrin derivatives, a variation in the emission of porphyrazines, a subtle increase in the zeta potential compared to the isolated CD particles, and a variation in the translational diffusion coefficient. It was also found that upon combination with the CD, changes in the photophysical properties of the macrocycles occur, for example, the fluorescence quantum yield of H2Pz increases from 0.81 ± 0.03% to 1.97 ± 0.05% while the singlet oxygen quantum yield of H2P increases ca. 70%. These results exemplify the capacity of CD to boost some properties of photosensitizers that are key for photodynamic therapy applications.

Photoimmuno-Lure Nanoplatform for Enhancing T Cell Expansion in Glioblastoma via Synergistic Treatment of Photodynamic Therapy and Immune Checkpoint Inhibition

The immunosuppressive tumor microenvironment (TME) of glioblastoma (GBM) limits the efficacy of immune checkpoint inhibitors (ICI), primarily due to the absence of cytotoxic T (Tc) cells. In this study, a photoimmuno-lure nanoplatform is presented that combines amphiphilic photosensitizers (PSs) with Atezolizumab leading to the modulation of the TME of GBM and improvement of the therapeutic efficacy through synergistic photodynamic therapy (PDT). The amphiphilic PSs exhibited four-fold higher GBM specificity, superior photostability, and enhanced singlet oxygen generation efficiency (1O2ΦΔ: 0.92) compared to conventional PSs. In in vitro GBM cell lines, amphiphilic PSs increased immune activation cytokines and improved ICI responsiveness compared to single ICI treatment. In addition, similar results are acquired in a GBM 3D spheroid model, showing significantly elevated Tc cell activation. In orthotopic in vivo GBM model, the nanoplatform achieved a 100% survival rate for up to 60 days. Immunological analysis revealed each 2.36-fold, 4.19-fold increase in activated dendritic cells and Tc cells respectively, and significant reductions in MDSCs (0.48-fold) and regulatory T cells (0.5-fold). As a result, this study demonstrates the potential of the synergistic photoimmuno-lure nanoplatform as a clinical solution to overcome the immunosuppressive TME of GBM and activate innate and adaptive immunity for effective treatment.

Porphyrin-Derived Carbon Dots for Red-Light Activated Photodynamic Therapy of Breast Cancer

In recent years, cancer has emerged as a major global health threat, ranking among the top causes of mortality. While treatments such as surgery, immunotherapy, radiation therapy, and chemotherapy remain widely used, photodynamic therapy has been gaining significant interest. Most of the photosensitizing agents employed in clinical settings are derived from tetrapyrrolic frameworks, including porphyrins, chlorins, and phthalocyanines. Although these compounds have demonstrated therapeutic effectiveness, they suffer from critical drawbacks, such as limited solubility in water and inadequate (photo)stability. To address these issues, herein, the formulation of the previously reported and promising photosensitizer tetrakis(4-carboxyphenyl) porphyrin into carbon dots is reported. The carbon dots were found with enhanced aqueous solubility, high (photo)stability, and greater singlet oxygen quantum yield overcoming the limitations of the molecular photosensitizer. While being nontoxic in the dark, the carbon dots induced a phototherapeutic effect in breast cancer cells and multicellular tumor spheroids.

Lipoprotein-inspired in situ activatable photo-theranostic nitrobenzoselenadiazole-cholesterol for overcoming glioblastoma

Photo-theranostic materials are designed for both diagnostic imaging and therapeutic applications under specific light sources, particularly in translational medicine. While various photo-theranostic materials have been developed for disease treatment, their cooperative effects on biologically abundant species, such as proteins, have rarely been studied in terms of biological activity. In this work, we disclose a photo-theranostic agent (named NBSD-Chol) based on nitrobenzoselenadiazole (NBSD) and cholesterol (Chol), which is activatable in situ through lipoprotein hybridization. NBSD-Chol demonstrates outstanding potential for cancer imaging and photodynamic therapy (PDT) due to its unique properties, including (i) tumor targeting after oral uptake, (ii) tumor visualization under light irradiation for image-guided surgery, (iii) superior PDT effects, and (iv) downgrading hazard ratios (HR) related to clinically critical proteins. Overall, this work contributes to advancing translational medicine by developing innovative treatments for cancer using visible light, ushering in a new era of intraoperative technology and photodynamic fluorescence-guided surgical agents.

Small Molecule-Mediated Photothermal Therapy Induces Apoptosis in Cancer Cells

Cancer remains as one of the most life-threatening diseases in the whole world. Most of the therapeutic strategies to eradicate cancer are highly invasive, leading to severe injury and trauma to the patients. In recent times, phototherapy has emerged as one of the noninvasive therapeutic strategies for cancer treatment. However, development of novel small-molecule photothermal agents remains a major challenge. To address this, herein, a small molecule library having aromatic substituted-3-methoxy-pyrrole and 2-(3-cyano-4,5,5-trimethylfuran-2(5 H)-ylidene) malononitrile in a concise synthetic strategy is designed and synthesized. One of the library members (7H) self-assembles into spherical-like nanoparticles having <100 nm size in water and is found to exhibit remarkable increase in temperature under 740 nm near-infrared (NIR) light. Interestingly, compound 7H homes into the lysosomal compartments and the lipid droplets in the HCT-116 colon cancer cells within 3 h and induces photothermal effect followed by generation of reactive oxygen species while irradiating under 740 nm NIR light for 10 min. Moreover, 7H triggers programmed cell death (apoptosis) to induce remarkable HCT-116 cell killing. This small molecule-mediated photothermal effect shows potential to be an interesting tool for the next-generation noninvasive cancer phototherapy.

Light exposure of tetra-cationic porphyrins containing peripheral Pd(II)-bipyridyl complexes and the induced effects on purified DNA molecule, fibroblast and melanoma cell lines

Photodynamic therapy (PDT) combines a light source, oxygen, and a photosensitizer (PS) to generate reactive oxygen species (ROS) for treating diseases. In this study, we evaluated two meso-tetra-pyridyl porphyrins with [Pd(bpy)Cl]+, namely 3-PdTPyP and 4-PdTPyP, as PS for PDT application. DNA interaction was assessed by spectroscopic measurements (UV-Vis and fluorescence emission), viscosity analysis, and molecular docking simulations. The results indicate that Pd(II)-porphyrins do not intercalate into DNA, suggesting that the minor groove is the primary interaction site, mainly through van der Waals forces. These metalloporphyrins effectively induced nitrogenous bases oxidation, particularly in purines, after white light irradiation. The induced DNA lesions were able to inactivate plasmid DNA metabolism (DNA replication and transcription) in a bacterial model. 3-PdTPyP and 4-PdTPyP significantly decreased the viability of treated melanoma cell lines (A375 and B16-F10), demonstrating that melanoma cell lines were more sensitive to these Pd(II)-porphyrins than the fibroblast cell line (L929). Moreover, 3-PdTPyP was more photototoxic to A375 cells (IC50 = 0.43 μM), whereas 4-PdTPyP was more photototoxic to B16-F10 cells (IC50 = 0.51 μM). These findings suggest that these porphyrins are promising PS for future PDT research focused on skin cancer.

Activatable Photosensitizers: From Fundamental Principles to Advanced Designs

Photodynamic therapy (PDT) is a promising treatment that uses light to excite photosensitizers in target tissue, producing reactive oxygen species and localized cell death. It is recognized as a minimally invasive, clinically approved cancer therapy with additional preclinical applications in arthritis, atherosclerosis, and infection control. A hallmark of ideal PDT is delivering disease-specific cytotoxicity while sparing healthy tissue. However, conventional photosensitizers often suffer from non-specific photoactivation, causing off-target toxicity. Activatable photosensitizers (aPS) have emerged as more precise alternatives, offering controlled activation. Unlike traditional photosensitizers, they remain inert and photoinactive during circulation and off-target accumulation, minimizing collateral damage. These photosensitizers are designed to "turn on" in response to disease-specific biostimuli, enhancing therapeutic selectivity and reducing off-target effects. This review explores the principles of aPS, including quenching mechanisms stemming from activatable fluorescent probes and applied to activatable photosensitizers (RET, PeT, ICT, ACQ, AIE), as well as pathological biostimuli (pH, enzymes, redox conditions, cellular internalization), and bioresponsive constructs enabling quenching and activation. We also provide a critical assessment of unresolved challenges in aPS development, including limitations in targeting precision, selectivity under real-world conditions, and potential solutions to persistent issues (dual-lock, targeting moieties, biorthogonal chemistry and artificial receptors). Additionally, it provides an in-depth discussion of essential research design considerations needed to develop translationally relevant aPS with improved therapeutic outcomes and specificity.

Tumor Treatment by Nano-Photodynamic Agents Embedded in Immune Cell Membrane-Derived Vesicles

Non-invasive phototherapy includes modalities such as photodynamic therapy (PDT) and photothermal therapy (PTT). When combined with tumor immunotherapy, these therapeutic approaches have demonstrated significant efficacy in treating advanced malignancies, thus attracting considerable attention from the scientific community. However, the progress of these therapies is hindered by inherent limitations and potential adverse effects. Recent findings indicate that certain therapeutic strategies, including phototherapy, can induce immunogenic cell death (ICD), thereby opening new avenues for the integration of phototherapy with tumor immunotherapy. Currently, the development of biofilm nanomaterial-encapsulated drug delivery systems has reached a mature stage. Immune cell membrane-encapsulated nano-photosensitizers hold great promise, as they can enhance the tumor immune microenvironment. Based on bioengineering technology, immune cell membranes can be designed according to the tumor immune microenvironment, thereby enhancing the targeting and immune properties of nano-photosensitizers. Additionally, the space provided by the immune cell membrane allows for the co-encapsulation of immunotherapeutic agents and chemotherapy drugs, achieving a synergistic therapeutic effect. At the same time, the timing of photodynamic therapy (PDT) can be precisely controlled to regulate the action timing of both immunotherapeutic and chemotherapy drugs. This article summarizes and analyzes current research based on the aforementioned advancements.

Bibliometric analysis of photodynamic research in bladder cancer: Trends and future directions

BACKGROUND

Recent years have seen the use of photodynamic technologies concerning the detection and therapy of bladder cancer (BC) due to their rapid development and well-established therapeutic impact. However, a thorough analysis and bibliometric assessment of photodynamic technologies publishing trends in BC has not been completed yet.

METHODS

Retrieving bibliographies from the Web of Science Core Collection limited the publication date to December 31, 2023, from January 1, 2004. We used VOSviewer (Version 1.6.19) and CiteSpace (Version 6.4 R1) for both statistical and visualization analysis.

RESULTS

We selected a total of 870 documents for analysis. The yearly publication findings show notable upward patterns over the last two decades. The Kochi Medical School in Japan was the most productive school, while the USA was the most productive nation. Japanese researcher Inoue Keiji published the highest number of photodynamic -related articles in BC. The most quoted and prolific journals were the Photodynamic Therapy and Photodiagnosis. According to the keyword analysis, the terms "cystoscopy," "carcinoma in situ," "drug delivery," "follow-up," "hexaminolevulinate," and "impact" are all relatively recent and hot field.

CONCLUSIONS

Our investigation produced a bibliometric outcome for the field, potentially opening up new research opportunities. We suggest that future research concentrate on in-situ carcinoma identification, photosensitizer invention, medication delivery enhancement, and photodynamic technology follow-up in BC.

Photodynamic priming with red light triggers adaptive immune responses in a pancreatic cancer mouse model

The poor response of pancreatic ductal adenocarcinoma (PDAC) to treatment, including immunotherapy, is attributed to its tumor microenvironment (TME). An ongoing challenge is the desmoplastic and immunosuppressed TME that evades immune surveillance. Here, we investigate transient modulation of the TME to overcome immunosuppression using a light-activated process, termed photodynamic priming (PDP). As a first step, this study captures the temporal dynamics of variations in immune infiltrates and subsequent immune responses in the TME, spleen, and blood of the KPC mouse model of PDAC post-PDP. In response to PDP, there were transient increases in tumor infiltrating lymphocytes (TIL) in tumors. The TIL population post-PDP includes an enrichment of CD8+ T cells, accompanied by temporal increases in PD-1, CTLA-4, and TIM-3 immune checkpoints on both CD8+ T and CD4+ T cells. Significant increases in CD11C+MHC-11+ dendritic cells and proliferating lymphocytes are observed in the spleen within several hours post-tumor PDP, suggesting initiation of adaptive immune responses. These observations are followed by an expansion of CD44+CD62-CD8+ effector memory T cells in the blood over several days as evidence of a systemic immune response. Post-PDP TME alterations also included the reduced formation of blood (CD31+) and lymphatic (Lyve-1+) vessels as well as decreases in PD-L1 and collagen content. Collectively, these data suggest that PDP helps to mitigate immunosuppressive mechanisms and promote enhanced tumor permeability. The temporal dynamics of the processes elucidated here pave the way to develop strategies in future work for combined PDP-immunotherapy utilizing the immune checkpoint expression dynamics for precision therapy.

Nanoparticles for Photodynamic Therapy of Breast Cancer: A Review of Recent Studies

Photodynamic therapy (PDT) is a therapeutic method based on the interaction between light and a photosensitizer. Supported by nanoparticles, this method represents a promising interdisciplinary approach for the treatment of many diseases. This article reviews the latest 2024 developments in the design and applications of nanoparticles dedicated to stand-alone PDT of breast cancer. Strategies to improve therapeutic efficacy by enhancing reactive oxygen species (ROS) production, precise delivery of photosensitizers and their stabilization in the systemic circulation are discussed, among others. Results from preclinical studies indicate significant improvements in therapeutic efficacy, including inhibition of tumor growth, reduction in metastasis and improvement of the immune microenvironment. The potential of these technologies to expand PDT applications in medicine and the need for further clinical trials to confirm their safety and efficacy are highlighted.

Cancer Photodynamic Therapy Enabled by Water-Soluble Chlorophyll Protein

Photodynamic therapy (PDT) has been utilized to treat various malignant cancers for more than a century. However, many photosensitizers (e.g., derivatives of porphyrins, chlorins, etc.) central to PDT are still suffering from limitations such as water insolubility, dark toxicity, photo/thermal-instability, difficult synthesis/preparation, and poor tumor selectivity. Numerous effective strategies include designing new synthetic photosensitizers by exploiting heavy atom effect, aggregation-induced emission effect (AIE), and electronic/energy effects (donor-acceptor, and Förster resonance energy transfer: FRET), and the linkage of activatable and targeting molecules has been developed to address one or more of these limitations. However, these structural modifications of photosensitizing organic molecules are synthetically challenging and unpredictable in terms of efficacy versus toxicity. Herein, we report a new and simple strategy for effective PDT by combining natural spinach-derived chlorophylls (photosensitizer) with natural water-soluble chlorophyll proteins (WSCPs) derived originally from plants and produced heterologously by bacteria (E. coli). The recombinant WSCPs (chlorophyll-WSCP) are tetrameric and stable under air/thermal conditions and importantly can produce highly reactive singlet oxygen under red/far-red light irradiation to induce cancer cell death. Our in vivo mouse model studies (melanoma xenografts) further validate the efficacy of the recombinant WSCPs as a new class of water-soluble, nontoxic, and highly efficient photosensitizers for PDT. This work represents the first example of the application of WSCPs in PDT and may advance the clinical applications of PDT for cancer treatment.

Applications and enhancement strategies of ROS-based non-invasive therapies in cancer treatment

Reactive oxygen species (ROS) play a crucial role in the pathogenesis of cancer. Non-invasive therapies that promote intracellular ROS generation, including photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT), have emerged as novel approaches for cancer treatment. These therapies directly kill tumor cells by generating ROS, and although they show great promise in tumor treatment, many challenges remain to be addressed in practical applications. Firstly, the inherent complexity of the tumor microenvironment (TME), such as hypoxia and elevated glutathione (GSH) levels, hinders ROS generation, thereby significantly diminishing the efficacy of ROS-based therapies. In addition, these therapies are influenced by their intrinsic mechanisms. To overcome these limitations, various nanoparticle (NP) systems have been developed to improve the therapeutic efficacy of non-invasive therapies against tumors. This review first summarizes the mechanisms of ROS generation for each non-invasive therapy and their current limitations, with a particular focus on the enhancement strategies for each therapy based on NP systems. Additionally, various strategies to modulate the TME are highlighted. These strategies aim to amplify ROS generation in non-invasive therapies and enhance their anti-tumor efficiency. Finally, the current challenges and possible solutions for the clinical translation of ROS-based non-invasive therapies are also discussed.

Ce6-GFFY is a novel photosensitizer for colorectal cancer therapy

Photodynamic therapy is an "old" strategy for cancer therapy featuring clinical safety and rapid working, but suitable photosensitizers for colorectal cancer therapy remain lacking. This study synthesized a novel photosensitizer termed Ce6-GFFY based on a self-assembling peptide GFFY and a photo-responsive molecule chlorin e6 (Ce6). Ce6-GFFY forms macroparticles with a diameter of ∼160 nm and possesses a half-life of 10 h, as well as an ideal tumor-targeting ability in mouse models. Ce6-GFFY effectively penetrates cells and generates numerous reactive oxygen species upon 660 nm laser irradiation. The reactive oxygen species promotes the accumulation of cytotoxic T cells and decrease of myeloid-derived suppressor cells in the tumor microenvironment through immunogenic cell death, thus prohibiting the growth of both primary and metastatic tumors after once treatment. This study not only provides a strategy for photosensitizer development but also confirms a promising application of Ce6-GFFY for colorectal cancer therapy.

Biodegradable semiconducting polymer nanoparticles for phototheranostics

Semiconducting polymer nanoparticles (SPNs) have been widely applied for phototheranostics. However, the disadvantage of in vivo long-term metabolism greatly suppresses the clinical application of SPNs. To improve the metabolic rate and minimize the long-term toxicity of SPNs, biodegradable semiconducting polymers (BSPs), whose backbones may be degraded under certain conditions, have been designed. This review summarizes recent advances in BSP-constructed nanoparticles (BSPNs) for phototheranostics. BSPs are divided into two categories: conjugated backbone degradable BSPs (CBD-BSPs) and non-conjugated backbone degradable BSPs (NCBD-BSPs), based on the feature of chemical structure. The biological applications, including cancer imaging and combination therapy, of these BSPNs are described. Finally, the conclusion and future perspectives of this field are discussed.

Cancer stem cell populations are resistant to 5-aminolevulinic acid-photodynamic therapy (5-ALA-PDT)

Photodynamic therapy (PDT) is a minimally invasive treatment approved for many types of cancers. PDT involves the administration of photoactive substances called photosensitizers (PS) that selectively accumulate in cancer cells and are subsequently excited/activated by irradiation with light at wavelengths of optimal absorbance. Activated PS leads to the generation of singlet oxygen and other reactive oxygen species (ROS), promoting cancer cell death. 5-aminolevulinic acid (5-ALA) is a naturally occurring PS precursor, which is metabolically converted to the PS, protoporphyrin IX (PPIX). Although 5-ALA-PDT is effective at killing cancer cells, in prior studies conducted by our group we normally observed in in vitro experiments that approximately 5-10% of cells survive 5-ALA-PDT, which served as an impetus for further investigation. Identifying the mechanisms of resistance to 5-ALA-PDT-mediated cell death is important to prevent tumor recurrence following 5-ALA-PDT. Previously, we reported that oncogenic activation of Ras/MEK promotes PPIX efflux and reduces cellular sensitivity to 5-ALA-PDT through increased expression of ABCB1 transporter. As cancer stem cells (CSCs) are known to drive resistance to other cancer treatments and have high efflux of chemotherapeutic agents via ABC-family transporters, we hypothesize that CSCs underlie 5-ALA-PDT resistance. In this study, we determined (1) if CSCs are resistant to 5-ALA-PDT and (2) if CSCs play roles in establishing resistant populations of 5-ALA-PDT. When we compared CSC populations before and after 5-ALA-PDT, we found that CSCs were less susceptible to 5-ALA-PDT. Moreover, we found that the CSC population was enriched in 5-ALA-PDT-resistant cell lines compared to the parental cell line. Our results indicate that CSCs are not sensitive to 5-ALA-PDT, which may contribute to establishment of 5-ALA-PDT resistance.

Photosensitizer formulations in photodynamic therapy of age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive degenerative disease that leads to visual impairment, predominantly affecting the elderly. Despite significant advancements in treatment, a definitive cure remains elusive. Current therapeutic strategies only slow down disease progression, inhibiting abnormal blood vessels growth, and preserving or improving vision. Among these strategies, photodynamic therapy (PDT) has emerged as a promising treatment, particularly for neovascular form, the most severe form of the disease. Although several photosensitizers (PS) have been developed, only one has received clinical approval for use in AMD. This treatment involves the intravenous administration of a photosensitizing agent that preferentially accumulates in the abnormal blood vessels beneath the macula. Upon activation by targeted laser light, the PS triggers photochemical reactions, leading to vascular occlusion and the reduction of choroidal neovascularization. This review provides a comprehensive overview of both experimental and clinical studies on PDT for AMD, discussing the current state of research, challenges in treatment optimization, and potential future directions to enhance this therapeutic approach.

Transition metal complexes: next-generation photosensitizers for combating Gram-positive bacteria

The rise of antibiotic-resistant Gram-positive bacterial infections poses a significant threat to public health, necessitating the exploration of alternative therapeutic strategies. A photosensitizer (PS) can convert energy from absorbed photon into reactive oxygen species (ROS) for damaging bacteria. This photoinactivation action bypassing conventional antibiotic mechanism is less prone to resistance development, making antibacterial photodynamic therapy (aPDT) highly efficient in combating Gram-positive bacteria. Photodynamic transition metal complexes leveraging the unique properties of metals to enhance the aPDT activity are the next-generation PS. This review provides an overview of metal-based PS for combating Gram-positive bacteria. Based on the structures, these metal-PS could be mainly classified as metal-tetrapyrrole derivatives, ruthenium complexes, iridium complexes, and zinc complexes. PS based on complexes of other transition metals such as silver, cobalt, and rhenium are also presented. Finally, we summarize the advantages and shortcomings of these metal- PS, conclude some critical aspects impacting their aPDT performances and give a perspective on their future development.

Biofilm battle: New transformative tactics to tackle the bacterial biofilm infections

Bacterial biofilm infections are the root cause of persistent infections and the prevalence of resistance to specific or multiple antibiotics. Biofilms have unique features that provide a protective environment for bacteria under various stress conditions and contribute significantly to the pathogenesis of chronic infections. They cover bacterial cells with a self-produced extracellular polymeric matrix, effectively hiding the bacterial cells and their targets. Conventional therapies cannot effectively treat and control bacterial biofilm infections. Therefore, advanced therapeutic means like microneedles, targeted tissue therapy, phage therapy, nanodrug therapy, combination drug therapy, microbial therapy, and immune cell hijacking therapy are needed to tackle the complex issue. These advanced therapies have shown promising results not only in bacterial biofilm infections but also in diseases such as cancer and genetic disorders. Due to their unique features and mechanisms, they significantly contribute to preventing bacterial infections by disrupting biofilm. This article aims to serve as a comprehensive overview of the ongoing battle against biofilms with transformative therapies. This article compiles advancements in new therapies that have demonstrated effective roles in the disruption of bacterial biofilms. We also discuss the current developments and Food and Drug Administration-approved status of these therapies. Additionally, this article summarizes the limitations and future steps needed for these therapies in the field of bacterial biofilm prevention. Thus, these therapies represent the future of preventing bacterial biofilm infections and could be also effective in the reversal of resistance.

Chlorin e6: a promising photosensitizer of anti-tumor and anti-inflammatory effects in PDT

Photodynamic therapy (PDT) involves the activation of photosensitizers (PSs) by visible laser light at the target site to catalyze the production of reactive oxygen species, resulting in tumor cell death and blood vessel closure. The efficacy of PDT depends on the PSs, the amount of oxygen, and the intensity of the excitation laser. PSs have been extensively researched, and great efforts have been made to develop an ideal photosensitizer. Chlorin-e6 is an FDA-approved second-generation PSs that has attracted widespread research interest in the medical field, especially with respect to antitumor and anti-inflammatory activity. Chlorin-e6 possesses the advantages of a large absorption coefficient, high strength, low residue in the body, and relatively high safety and thus has promising application prospects. Here we review the use of chlorin-e6 in PDT and discuss the prospects of further development of this technology.

pH-sensitive phthalocyanine-loaded polymeric nanoparticles as a novel treatment strategy for breast cancer

Novel pH-sensitive polymeric photosensitizer carriers from the phthalocyanine (Pc) group were investigated as potential photodynamic therapy drugs for the treatment of breast cancer. Their high antiproliferative activity was confirmed by photocytotoxicity studies, which indicated their high efficacy and specificity toward the SK-BR-3 cell line. Importantly, the Pcs encapsulated in the polymeric nanoparticle (NP) carrier exhibited a much better penetration into the acidic environment of tumor cells than their free form. The investigated Pc4-NPs and TT1-NPs exhibited a high selectivity to healthy fibroblasts as well as non-toxicity without irradiation. This paper describes the detailed mechanism of action of the evaluated compounds by measuring reactive oxygen species (ROS), including singlet oxygen; imaging cellular localization; and analyzing key signaling pathway proteins. An additional advantage of the evaluated compounds is their ability to inhibit the Akt protein expression, including its phosphorylation, which the Western blot test confirmed. This is particularly important because breast cancers often overexpress the HER-2 receptor-related signaling proteins. Moreover, an analysis of proteins such as GLUT-1, HO-1, phospho-p42/44, and BID revealed the significant involvement of ROS in disrupting cellular homeostasis, thereby leading to the induction of oxidative stress and resulting in apoptotic cell death.

Mitochondrial dysfunction route as a possible biomarker and therapy target for human cancer

Mitochondria are vital organelles found within living cells and have signalling, biosynthetic, and bioenergetic functions. Mitochondria play a crucial role in metabolic reprogramming, which is a characteristic of cancer cells and allows them to ensure a steady supply of proteins, nucleotides, and lipids to enable rapid proliferation and development. Their dysregulated activities have been associated with the growth and metastasis of different kinds of human cancer, particularly ovarian carcinoma. In this review, we briefly demonstrated the modified mitochondrial function in cancer, including mutations in mitochondrial DNA (mtDNA), reactive oxygen species (ROS) production, dynamics, apoptosis of cells, autophagy, and calcium excess to maintain cancer genesis, progression, and metastasis. Furthermore, the mitochondrial dysfunction pathway for some genomic, proteomic, and metabolomics modifications in ovarian cancer has been studied. Additionally, ovarian cancer has been linked to targeted therapies and biomarkers found through various alteration processes underlying mitochondrial dysfunction, notably targeting (ROS), metabolites, rewind metabolic pathways, and chemo-resistant ovarian carcinoma cells.

Recent Advances in Strategies to Enhance Photodynamic and Photothermal Therapy Performance of Single-Component Organic Phototherapeutic Agents

Photodynamic therapy (PDT) and photothermal therapy (PTT) have emerged as promising treatment options, showcasing immense potential in addressing both oncologic and nononcologic diseases. Single-component organic phototherapeutic agents (SCOPAs) offer advantages compared to inorganic or multicomponent nanomedicine, including better biosafety, lower toxicity, simpler synthesis, and enhanced reproducibility. Nonetheless, how to further improve the therapeutic effectiveness of SCOPAs remains a challenging research area. This review delves deeply into strategies to improve the performance of PDT or PTT by optimizing the structural design of SCOPAs. These strategies encompass augmenting reactive oxygen species (ROS) generation, mitigating oxygen dependence, elevating light absorption capacity, broadening the absorption region, and enhancing the photothermal conversion efficiency (PCE). Additionally, this review also underscores the ideal strategies for developing SCOPAs with balanced PDT and PTT. Furthermore, the potential synergies are highlighted between PDT and PTT with other treatment modalities such as ferroptosis, gas therapy, chemotherapy, and immunotherapy. By providing a comprehensive analysis of these strategies, this review aspires to serve as a valuable resource for clinicians and researchers, facilitating the wider application and advancement of SCOPAs-mediated PDT and PTT.

Participation of lipids in the tumor response to photodynamic therapy and its exploitation for therapeutic gain

Hydroperoxides of unsaturated membrane lipids (LOOHs) are the most abundant non-radical intermediates generated by photodynamic therapy (PDT) of soft tissues such as tumors and have far longer average lifetimes than singlet oxygen or oxygen radicals formed during initial photodynamic action. LOOH-initiated post-irradiation damage to remaining membrane lipids (chain peroxidation) or to membrane-associated proteins remains largely unrecognized. Such after-light processes could occur during clinical oncological PDT, but this is not well-perceived by practitioners of this therapy. In general, the pivotal influence of lipids in tumor responses to PDT needs to be better appreciated. Of related importance is the fact that most malignant tumors have dramatically different lipid metabolism compared with healthy tissues, and this too is often ignored. The response of tumors to PDT appears especially vulnerable to manipulations within the tumor lipid microenvironment. This can be exploited for therapeutic gain with PDT, as exemplified here by the combined treatment with the antitumor lipid edelfosine.

Cell-Penetrating Peptide Like Anti-Programmed Cell Death-Ligand 1 Peptide Conjugate-Based Self-Assembled Nanoparticles for Immunogenic Photodynamic Therapy

The tumor-specific efficacy of the most current anticancer therapeutic agents, including antibody-drug conjugates (ADCs), oligonucleotides, and photosensitizers, is constrained by limitations such as poor cell penetration and low drug delivery. In this study, we addressed these challenges by developing, a positively charged, amphiphilic Chlorin e6 (Ce6)-conjugated, cell-penetrating anti-PD-L1 peptide nanomedicine (CPPD1) with enhanced cell and tissue permeability. The CPPD1 molecule, a bioconjugate of a hydrophobic photosensitizer and strongly positively charged programmed cell death-ligand 1 (PD-L1) binding cell-penetrating peptide (CPP), is capable of self-assembling into nanoparticles with an average size of 199 nm in aqueous solution without the need for any carriers. These carrier-free nanoparticles possess the ability to penetrate the cell membrane of cancer cells and target tumors expressing PD-L1 on their surface. Notably, CPPD1 nanoparticles effectively blocked programmed cell death-1 (PD-1)/PD-L1 interactions and reduced PD-L1 expression via lysosomal degradation. They also demonstrated the responsiveness of CPPD1 nanoparticles in photodynamic therapy (PDT) to a 635 nm laser, leading to the generation of ROS, and induction of various immunogenic cell deaths (ICD). Highly penetrating CPPD1 nanoparticles could immunogenically modulate the microenvironment of CT26 cancer and were also effective in treating abscopal metastatic tumors, addressing major limitations of traditional PDT.

High-Intensity Focused Ultrasound Ablation for Primary or Salvage Prostate Cancer Therapy: Initial Outcomes in the Veteran Healthcare Setting

High-Intensity Focused Ultrasound (HIFU) provides comparable oncologic, erectile, and urinary outcomes to standard-of-care options for localized prostate cancer. This study reports the largest United States series of HIFU in veterans for both primary and salvage therapies. We retrospectively analyzed the outcomes of 43 veterans treated at the Michael E. DeBakey Veterans Affairs Medical Center from 2018 to 2022. Primary endpoints included prostate-specific antigen (PSA) reduction and local recurrence rates. Secondary endpoints included 30-day complications, Sexual Health Inventory for Men (SHIM), and American Urological Association Symptom Score (AUASS). In our study, 31 veterans (72.1%) received primary treatment and 12 (27.9%) received salvage therapy, with a median follow-up of 23 and 25 months, respectively. Median PSA nadir was 0.16 for primary and 0.12 for salvage groups, with PSA reduction stable over 30 months. Local recurrence occurred in 16.1% of primary and 16.6% of salvage patients. SHIM scores and AUASS were not statistically different before and after HIFU therapy. Short- and intermediate-term results suggest HIFU is a safe and effective treatment option with excellent potency and preserved urinary function, as well as adequate oncological control for primary and salvage therapies for localized prostate cancer in veterans.

Breaking the resistance: integrative approaches with novel therapeutics against Klebsiella pneumoniae

Klebsiella pneumoniae is a leading cause of anti-microbial resistance in healthcare-associated infections that have posed a severe threat to neonatal and wider community. The escalating crises of antibiotic resistance have compelled researchers to explore an innovative arsenal beginning from natural resources to chemical modifications in order to overcome the ever-increasing resistance issues. The present review highlights the drug discovery efforts with a special focus on cutting-edge strategies in the hunt for potential drug candidates against MDR/XDR Klebsiella pneumoniae. Nature's bounty constituting plant extracts, essential oils, fungal extracts, etc. holds promising anti-bacterial potential especially when combined with existing antibiotics. Further, enhancing these natural products with synthetic moieties has improved their effectiveness, creating a bridge between the natural and synthetic world. Conversely, the synthetically modified novel scaffolds have been also designed to meticulously target specific sites. Furthermore, we have also elaborated various emerging strategies for broad-spectrum infections caused by K. pneumoniae, which include anti-microbial peptides, nanotechnology, drug repurposing, bacteriophage, photodynamic, and multidrug therapies. This review further addresses the challenges confronted by the research community and the future way forward in the field of drug discovery against multi-resistant bacterial infections.

Use of UMFNPs/Ce6@MBs in multimodal imaging-guided sono-photodynamic combination therapy for hepatocellular carcinoma

Early diagnosis of liver cancer and appropriate treatment options are critical for obtaining a good prognosis. However, due to technical limitations, it is difficult to make an early and accurate diagnosis of liver cancer, and the traditional imaging model is relatively simple. Therefore, we synthesized multifunctional diagnostic/therapeutic nanoparticles, UMFNPs/Ce6@MBs, loaded with ultra-small manganese ferrite nanoparticles (UMFNPs) and chlorin e6 (Ce6). This nanoplatform can take full advantage of hypoxia, acidic pH (acidosis) and increased levels of reactive oxygen species (e.g. H2O2) in the tumor microenvironment (TME). Specific imaging and drug release can also enhance tumor therapy by modulating the hypoxic state of the TME to achieve the combined effect of sonodynamic therapy and photodynamic therapy (SPDT). In addition, the prepared UMFNPs/Ce6@MBs have H2O2 and pH-sensitive biodegradability and can release UMFNPs and photosensitizer Ce6 in the TME while producing O2 and Mn2+. The obtained Mn2+ ion nanoparticles can be used for T1 magnetic resonance imaging of tumor-bearing mice, and the released Ce6 can provide fluorescence imaging function at the same time. Because UMFNPs/Ce6@MB ultrasonic microbubbles show good ultrasonic imaging results, UMFNPs/Ce6@MBs can simultaneously provide multi-modal imaging functions for magnetic resonance imaging (MRI), ultrasound and fluorescence imaging. In conclusion, UMFNPs/Ce6@MBs realize the synergistic treatment of SDT and PDT under multi-mode near-infrared fluorescence imaging and CEUS monitoring, demonstrating its great potential in tumor precision medicine.

A new era of cancer phototherapy: mechanisms and applications

The past decades have witnessed great strides in phototherapy as an experimental option or regulation-approved treatment in numerous cancer indications. Of particular interest is nanoscale photosensitizer-based phototherapy, which has been established as a prominent candidate for advanced tumor treatment by virtue of its high efficacy and safety. Despite considerable research progress on materials, methods and devices in nanoscale photosensitizing agent-based phototherapy, their mechanisms of action are not always clear, which impedes their practical application in cancer treatment. Hence, from a new perspective, this review elaborates the working mechanisms, involving impairment and moderation effects, of diverse phototherapies on cells, organelles, organs, and tissues. Furthermore, the most current available phototherapy modalities are categorized as photodynamic, photothermal, photo-immune, photo-gas, and radio therapies in this review. A comprehensive understanding of the inferiority and superiority of various phototherapies will facilitate the advent of a new era of cancer phototherapy.

Advancements and challenges in brain cancer therapeutics

Treating brain tumors requires a nuanced understanding of the brain, a vital and delicate organ. Location, size, tumor type, and surrounding tissue health are crucial in developing treatment plans. This review comprehensively summarizes various treatment options that are available or could be potentially available for brain tumors, including physical therapies (radiotherapy, ablation therapy, photodynamic therapy, tumor-treating field therapy, and cold atmospheric plasma therapy) and non-physical therapies (surgical resection, chemotherapy, targeted therapy, and immunotherapy). Mechanisms of action, potential side effects, indications, and latest developments, as well as their limitations, are highlighted. Furthermore, the requirements for personalized, multi-modal treatment approaches in this rapidly evolving field are discussed, emphasizing the balance between efficacy and patient safety.

Omics-Enhanced Nanomedicine for Cancer Therapy

Cancer nanomedicine has emerged as a promising approach to overcome the limitations of conventional cancer therapies, offering enhanced efficacy and safety in cancer management. However, the inherent heterogeneity of tumors presents increasing challenges for the application of cancer nanomedicine in both diagnosis and treatment. This heterogeneity necessitates the integration of advanced and high-throughput analytical techniques to tailor nanomedicine strategies to individual tumor profiles. Omics technologies, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and more, provide unparalleled insights into the molecular and cellular mechanisms underlying cancer. By dissecting tumor heterogeneity across multiple levels, these technologies offer robust support for the development of personalized and precise cancer nanomedicine strategies. In this review, the principles, techniques, and applications of key omics technologies are summarized. Especially, the synergistic integration of omics and nanomedicine in cancer therapy is explored, focusing on enhanced diagnostic accuracy, optimized therapeutic strategies and the assessment of nanomedicine-mediated biological responses. Moreover, this review addresses current challenges and outlines future directions in the field of omics-enhanced nanomedicine. By offering valuable insights and guidance, this review aims to advance the integration of omics with nanomedicine, ultimately driving improved diagnostic and therapeutic strategies for cancer.

Tumor energy metabolism: implications for therapeutic targets

Tumor energy metabolism plays a crucial role in the occurrence, progression, and drug resistance of tumors. The study of tumor energy metabolism has gradually become an emerging field of tumor treatment. Recent studies have shown that epigenetic regulation is closely linked to tumor energy metabolism, influencing the metabolic remodeling and biological traits of tumor cells. This review focuses on the primary pathways of tumor energy metabolism and explores therapeutic strategies to target these pathways. It covers key areas such as glycolysis, the Warburg effect, mitochondrial function, oxidative phosphorylation, and the metabolic adaptability of tumors. Additionally, this article examines the role of the epigenetic regulator SWI/SNF complex in tumor metabolism, specifically its interactions with glucose, lipids, and amino acids. Summarizing therapeutic strategies aimed at these metabolic pathways, including inhibitors of glycolysis, mitochondrial-targeted drugs, exploitation of metabolic vulnerabilities, and recent developments related to SWI/SNF complexes as potential targets. The clinical significance, challenges, and future directions of tumor metabolism research are discussed, including strategies to overcome drug resistance, the potential of combination therapy, and the application of new technologies.

Correction of Multispectral Singlet Oxygen Luminescent Dosimetry (MSOLD) for Tissue Optical Properties in Photofrin-Mediated Photodynamic Therapy

The direct detection of singlet-state oxygen (1O2) constitutes the holy grail dosimetric method for type-II photodynamic therapy (PDT), a goal that can be quantified using multispectral singlet oxygen near-infrared luminescence dosimetry (MSOLD). The optical properties of tissues, specifically their scattering and absorption coefficients, play a crucial role in determining how the treatment and luminescence light are attenuated. Variations in these properties can significantly impact the spatial distribution of the treatment light and hence the generation of singlet oxygen and the detection of singlet oxygen luminescence signals. In this study, we investigated the impact of varying optical properties on the detection of 1O2 luminescence signals during Photofrin-mediated PDT in tissue-mimicking phantoms. For comparison, we also conducted Monte Carlo (MC) simulations under the same conditions. The experimental and simulations are substantially equivalent. This study advances the understanding of MSOLD during PDT.

Advancing gastric cancer treatment: nanotechnology innovations and future prospects

Gastric cancer (GC) is the fifth most common cancer worldwide, particularly prevalent in Asia, especially in China, where both its incidence and mortality rates are significantly high. Meanwhile, nanotechnology has demonstrated great potential in the treatment of GC. In particular, nanodrug delivery systems have improved therapeutic efficacy and targeting through various functional modifications, such as targeting peptides, tumor microenvironment responsiveness, and instrument-based methods. For instance, silica (SiO2) has excellent biocompatibility and can be used as a drug carrier, with its porous structure enhancing drug loading capacity. Polymer nanoparticles regulate drug release rates and mechanisms by altering material composition and preparation methods. Lipid nanoparticles efficiently encapsulate hydrophilic drugs and promote cellular uptake, while carbon-based nanoparticles can be used in biosensors and drug delivery. Targets such as integrins, HER2 receptors, and the tumor microenvironment have been used to improve drug efficacy in GC treatment. Nanodrug delivery techniques not only enhance drug efficacy and delivery capabilities but also selectively target tumor cells. Currently, there is a lack of systematic summarization and synthesis regarding the relationship between nanodrug delivery systems and GC treatment, which to some extent hinders researchers and clinicians from efficiently searching for and referencing related studies, thereby reducing work efficiency. This study aims to systematically summarize the existing research on the relationship between nanodrug delivery systems and GC treatment, making it easier for professionals to search and reference, and thereby promoting further research on the role of nanodrug delivery systems and their clinical applications in GC. This review discusses the applications of functionalized nanocarriers in the treatment of GC in recent years, including surface modifications with targeted markers, the combination of phototherapy, chemotherapy, and immunotherapy, along with their advantages and challenges. It also examines the future prospects of targeted nanomaterials in GC treatment. The review particularly focuses on the combined application of nanocarriers in multiple treatment modalities, such as phototherapy, chemotherapy, and immunotherapy, demonstrating their potential in multimodal treatments. Furthermore, it thoroughly explores the specific challenges that nanocarriers face in GC treatment, such as biocompatibility, drug release control, and clinical translation issues, while providing a systematic outlook on future developments. Additionally, this study emphasizes the potential value and feasibility of nanocarriers in clinical applications, contrasting with most reviews that focus on basic research. Through these innovations, we offer new perspectives and directions for the development of nanotechnology in the treatment of GC.

Advances in smart nanotechnology-supported photodynamic therapy for cancer

Cancer has emerged as a formidable challenge in the 21st century, impacting society, public health, and the economy. Conventional cancer treatments often exhibit limited efficacy and considerable side effects, particularly in managing the advanced stages of the disease. Photodynamic therapy (PDT), a contemporary non-invasive therapeutic approach, employs photosensitizers (PS) in conjunction with precise light wavelengths to selectively target diseased tissues, inducing the generation of reactive oxygen species and ultimately leading to cancer cell apoptosis. In contrast to conventional therapies, PDT presents a lower incidence of side effects and greater precision in targeting. The integration of intelligent nanotechnology into PDT has markedly improved its effectiveness, as evidenced by the remarkable synergistic antitumor effects observed with the utilization of multifunctional nanoplatforms in conjunction with PDT. This paper provides a concise overview of the principles underlying PS and PDT, while also delving into the utilization of nanomaterial-based PDT in the context of cancer treatment.

Photodynamic therapy using hybrid nanoparticles comprising of upconversion nanoparticles and chlorin e6-bearing pullulan

With its minimal invasiveness, photodynamic therapy (PDT) is considered one of the most elegant modalities in cancer treatment. In this study, a facile hybrid nanoparticle was developed, composed of upconversion nanoparticles and chlorin e6-bearing pullulan, which can serve as a photosensitizer activated by a near-infrared red laser. Cell death induction in cancer cells was achieved through energy transfer from the near-infrared red laser emitted by the upconversion nanoparticles to chlorin e6. The therapeutic efficacy of our hybrid system surpassed that of the clinically available photosensitizer, Photofrin, and hybrid liposomes comprising upconversion nanoparticles and chlorin e6 were employed as control. Accumulation of our system in tumor tissue in tumor xenograft mice was primarily achieved through the enhanced permeability and retention (EPR) effect. The administered hybrids were excreted from each organ within 21 days after administration, minimizing the risk of undesirable side effects. Notably, our system exhibited 400 times higher PDT activity in tumor-bearing mice compared to the control groups. It also effectively inhibited metastasis.

Monocarbonyl curcuminoids as potential photosensitizers in photodynamic therapy against skin cancer

Two monocarbonyl dimethylamino curcuminoids, one derived from acetone (C3) and the second one from cyclohexane (C6), were synthesized aiming to study their photophysical properties and anticancer photodynamic potential. Compound C6 exhibited lower absorbance and fluorescence than C3. Photobleaching studies showed that C3 and C6 photostability behavior in DMSO differ significantly. C3 was completely photoconverted into a new species absorbing at lower wavelength than the parent compound, whereas, C6, upon a 30 min irradiation at λ = 440 nm with 15 mW/cm2 reached a photostationary phase where a smaller amount of the initial compound coexists with some photoproducts of higher and lower absorbance. Both compounds were able to generate significant amounts of ROS upon irradiation in an aqueous environment and exhibited successful intracellular localization in skin cancer cells (A431 cells). After dark cytotoxicity studies the concentrations of 5 μM and 1 μM for C3 and C6, respectively, were selected for the PDT assessment. C3 presented light dose-dependent photodynamic activity against A431 cells, resulting in 40 % cell viability after 12 min of light irradiation (440 nm, 15 mW/cm2). On the other side, C6 showed a biphasic light dose PDT effect with cell viability gradually decreasing up to 50 % after 5 min of light exposure, and then increasing again after 8 and 12 min of light exposure. The photodynamic performance of C6 may provide a new insight into the development of PSs with reduced prolonged photosensitivity.

Photodynamic Therapy against Colorectal Cancer Using Porphin-Loaded Arene Ruthenium Cages

Colorectal cancer (CRC) is the third most common cancer in the world, with an ongoing rising incidence. Despite secure advancements in CRC treatments, challenges such as side effects and therapy resistance remain to be addressed. Photodynamic therapy (PDT) emerges as a promising modality, clinically used in treating different diseases, including cancer. Among the main challenges with current photosensitizers (PS), hydrophobicity and low selective uptake by the tumor remain prominent. Thus, developing an optimal design for PS to improve their solubility and enhance their selective accumulation in cancer cells is crucial for enhancing the efficacy of PDT. Targeted photoactivation triggers the production of reactive oxygen species (ROS), which promote oxidative stress within cancer cells and ultimately lead to their death. Ruthenium (Ru)-based compounds, known for their selective toxicity towards cancer cells, hold potential as anticancer agents. In this study, we investigated the effect of two distinct arene-Ru assemblies, which lodge porphin PS in their inner cavity, and tested them as PDT agents on the HCT116 and HT-29 human CRC cell lines. The cellular internalization of the porphin-loaded assemblies was confirmed by fluorescence microscopy. Additionally, significant photocytotoxicity was observed in both cell lines after photoactivation of the porphin in the cage systems, inducing apoptosis through caspase activation and cell cycle progression disruptions. These findings suggest that arene-Ru assemblies lodging porphin PS are potent candidates for PDT of CRC.

Synthesis and evaluation of 5,15-diaryltetrabenzoporphyrins as photosensitizers for photo-diagnosis and photodynamic activity of tumors

Photodynamic therapy (PDT) is a well-established treatment modality, typically conducted with single-wavelength irradiation, which may not always be optimal for varying tumor locations and sizes. To address this, photosensitizers with absorption wavelengths ranging from 550 to 760 nm are being explored. Herein, a series of 5,15-diaryltetrabenzoporphyrins (Ar2TBPs) were synthesized. All compounds displayed obvious absorption at 550-700 nm (especially at ∼668 nm), intense fluorescence, efficient generation of singlet oxygen and good photodynamic antitumor effects. Notably, compound I3 (5,15-bis[(4-carboxymethoxy)phenyl]tetrabenzoporphyrin) showed excellent cytotoxicity against Eca-109 cell line upon red light irradiation, with an IC50 value of 0.45 μM, and phototherapeutic index of 25.8. Flow cytometry revealed that I3 could induce distinct cell apoptosis. In vivo studies revealed that compound I3 selectively accumulated at tumor site and exhibited outstanding PDT effect with antitumor activity under single-time administration and light irradiation, and revealed more efficiency than the clinical photosensitizer Verteporfin. These findings underscore the considerable promise of I3 as a robust theranostic agent, offering capabilities in real-time fluorescence imaging and serving as a potent photosensitizer for personalized and precise photodynamic therapy of tumors.

Effect of oxygen generating nanozymes on indocyanine green and IR 820 mediated phototherapy against oral cancer

The hypoxic environment within a solid tumor is a limitation to the effectiveness of photodynamic therapy. Here, we demonstrate the use of oxygen generating nanozymes (CeO2, Fe3O4, and MnO2) to improve the photodynamic effect. The optimized combination of process parameters for irradiation was obtained using the Box Behnken experimental design. Indocyanine green, IR 820, and their different combinations with oxygen generators were studied for their effect on oral carcinoma. Dynamic light scattering technique showed the average particle size of CeO2, MnO2, and Fe3O4 to be 211 ± 16, and 157 ± 28, 143 ± 19 nm with PDI of 0.23, 0.28 and 0.20 and a zeta potential of -2.6 ± 0.45, -2.4 ± 0.60 and  -6.1 ± 0.23 mV, respectively. The formation of metal oxides was confirmed using UV-visible, FTIR, and X-ray photon spectroscopies. The amount of dissolved oxygen produced by CeO2, MnO2, and Fe3O4 in the presence of H2O2 within 2 min was 1.7 ± 0.15, 1.7 ± 0.16, and 1.4 ± 0.12 mg/l, respectively. Growth inhibition studies in the FaDu oral carcinoma spheroid model showed a significant (P < 0.05) increase in growth reduction from 81 ± 2.9 and 88 ± 2.1% to 97 ± 1.2 and 99 ± 1.0% for ICG and IR 820, respectively, after irradiation (808 nm laser, 1 W/cm2, 5 min) in the presence of CeO2 (25 μg/ml). In conclusion, oxygen-generating nanozymes can improve the photodynamic effect of ICG and IR 820.

Capped Plasmonic Gold and Silver Nanoparticles with Porphyrins for Potential Use as Anticancer Agents-A Review

Photothermal therapy (PTT) and photodynamic therapy (PDT) are potential cancer treatment methods that are minimally invasive with high specificity for malignant cells. Emerging research has concentrated on the application of metal nanoparticles encapsulated in porphyrin and their derivatives to improve the efficacy of these treatments. Gold and silver nanoparticles have distinct optical properties and biocompatibility, which makes them efficient materials for PDT and PTT. Conjugation of these nanoparticles with porphyrin derivatives increases their light absorption and singlet oxygen generation that create a synergistic effect that increases phototoxicity against cancer cells. Porphyrin encapsulation with gold or silver nanoparticles improves their solubility, stability, and targeted tumor delivery. This paper provides comprehensive review on the design, functionalization, and uses of plasmonic silver and gold nanoparticles in biomedicine and how they can be conjugated with porphyrins for synergistic therapeutic effects. Furthermore, it investigates this dual-modal therapy's potential advantages and disadvantages and offers perspectives for future prospects. The possibility of developing gold, silver, and porphyrin nanotechnology-enabled biomedicine for combination therapy is also examined.

Modulating the phototoxicity and selectivity of a porphyrazine towards epidermal tumor cells by coordination with metal ions

Porphyrazines (Pzs) are porphyrin derivatives that show potential application as photosensitizers for photodynamic therapy (PDT), but are still far less explored in the literature. In this work, we evaluate how the photophysics and phototoxicity of the octakis(trifluoromethylphenyl)porphyrazine (H2Pz) against tumor cells can be modulated by coordination with Mg(II), Zn(II), Cu(II) and Co(II) ions. Fluorescence and singlet oxygen quantum yields for the Pzs were measured in organic solvents and in soy phosphatidylcholine (PC) liposomes suspended in water. While H2Pz and the respective complexes with Cu(II) and Co(II) showed very low efficiency to fluoresce and to produce 1O2, the Mg(II) and Zn(II) complexes showed significantly higher quantum yields in organic solvents. The fluorescence of these two Pzs in the liposomes was sensitive to the fluidity of the membrane, showing potential use as viscosity markers. The cytotoxicity of the compounds was tested in HaCaT (normal) and A431 (tumor) cells using soy PC liposomes as drug carriers. Despite the low 1O2 quantum yields in water, the Mg(II) and Zn(II) complexes showed IC50 values against A431 cells in the nanomolar range when activated with low doses of red LED light. Their phototoxicity was ca. three times higher for the tumor cells compared to the normal ones, showing promising application as photosensitizers for PDT protocols. Considering that H2Pz and the respective Co(II) and Cu(II) complexes were practically non-phototoxic to the cells, we demonstrate the importance of the central metal ion in the modulation of the photodynamic activity of porphyrazines.

Photoactivated rose bengal mitigates a fibrotic phenotype and improves cutaneous wound healing in full-thickness injuries

Healing of deep cutaneous wounds often results in detrimental sequelae, including painful and debilitating scars. Current therapies for full-thickness injuries that target specific phases of wound healing have moderate success; however, full resolution remains incomplete and negative consequences persist if skin homeostasis is not achieved. Photoactivated molecules can modulate cellular responses by generating reactive oxygen species and may provide a novel therapeutic option to improve wound healing. In the current study, we investigated the effects of Rose bengal (RB) dye in a preclinical model of full-thickness cutaneous injury. Monochromatic green light activates RB to generate ROS in the presence of oxygen, subsequently crosslinking collagen fibrils. In in vitro studies, we show that photoactivated RB is well tolerated by epidermal keratinocytes and dermal fibroblasts and can mitigate fibrotic signalling by downregulating collagen production. In a murine model of full-thickness injury, topically-applied and photoactivated RB closed wounds faster than control and vehicle treatments and showed significantly improved wound healing outcomes, including enhanced early granulation, better collagen organisation and increased vascularity in the presence of protracted tissue ROS. These data support an overall improved cutaneous wound healing profile after RB phototherapy and warrant further investigations into this versatile molecule.

Efficacy of Aminolevulinic Acid Mediated Photodynamic Therapy in the Treatment of Oral Premalignant Lesions: A Systematic Review

BACKGROUND

Aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) is considered as an effective treatment option for oral premalignant lesions. ALA is a Food and Drug Administration (FDA) approved second-generation photosensitizer (PS) used both orally as well as topically.

OBJECTIVE

This systematic review aims to evaluate the efficacy of ALA-PDT for the treatment of oral premalignant lesions.

METHODS

The focused question was, "Is ALA-PDT effective in the treatment of oral premalignant lesions?"A literature search was made in PubMed/Medline and GoogleScholar using different combinations of the following keywords: photodynamic therapy, oral premalignant lesions, oral leukoplakia (OL), erythroplakia, oral erythroleukoplakia (OEL), oral verrucous hyperplasia (OVH); and oral lichen planus (OLP). Review articles, preclinical studies, case-reports, commentaries, letters to the Editor, unpublished articles, studies on photodynamic therapy used in areas other than the oral cavityand, articles published in languages other than English were excluded. The relevant information was summarized.

RESULTS

There were initially 64 results for the above parameters; 47 studies were excluded, leaving 17 studies for analysis. Characteristics of the included studies, PS, and PDT protocol were summarized.

CONCLUSION

The outcome of the included studies suggested that ALA-PDT is an effective, easy to perform technique, well tolerated treatment with encouraging achievements in the treatment of oral premalignant lesions. No systemic side effects and skin photosensitivity were reported with topical ALA even within initial 48 hours after PDT, and patients were not required to avoid exposure to light following treatment. The clinical outcome of the ALA-PDT application, as reported in the studies, was also very promising, with either diminution in the size of the lesion or complete remission or improvement in signs and symptoms as well as reduced recurrence.

Antibiotic-free ocular sterilization while suppressing immune response to protect corneal transparency in infectious keratitis treatment

Clinical guidelines for infectious keratitis treatment require that anti-inflammatory drugs can only be used after infection elimination, which causes irreversible inflammatory damage to the cornea. In this work, photodynamic metal organic frameworks (PCN-224) were used as drug carrier to load Pt NPs with catalase-like activity and anti-inflammatory drug (Dexamethasone, DXMS) for endogenous oxygen generation and reduced corneal damage, respectively. The photodynamic therapy (PDT) effect was greatly enhanced in bacteria elimination and bacterial biofilms removal through catalysis of overexpressed hydrogen peroxide (H2O2, ∼8.0 and 31.0 μM in bacterial solution and biofilms, respectively) into oxygen by Pt NPs. More importantly, the cationic liposome modified PCN-224@Pt@DXMS@Liposomes (PPDL NPs) greatly enhanced the adhesion to negatively charged ocular surface and penetration into corneal barrier and bacterial biofilms. Both in vitro cell viability test and in vivo eye irritation tests proved good biocompatibility of PPDL NPs under 660 nm laser irradiation. Furthermore, PDT of PPDL NPs in rapid bacteria killing was verified through infectious keratitis animal model. The superior bactericidal effect of antibacterial materials could largely replace the bactericidal effect of the immune system. It is worth mentioning that this simultaneous sterilization and anti-inflammation treatment mode is a new exploration against the clinical treatment guidelines.

Emerging Trends and Innovations in the Treatment and Diagnosis of Atherosclerosis and Cardiovascular Disease: A Comprehensive Review towards Healthier Aging

Cardiovascular diseases (CVDs) are classed as diseases of aging, which are associated with an increased prevalence of atherosclerotic lesion formation caused by such diseases and is considered as one of the leading causes of death globally, representing a severe health crisis affecting the heart and blood vessels. Atherosclerosis is described as a chronic condition that can lead to myocardial infarction, ischemic cardiomyopathy, stroke, and peripheral arterial disease and to date, most pharmacological therapies mainly aim to control risk factors in patients with cardiovascular disease. Advances in transformative therapies and imaging diagnostics agents could shape the clinical applications of such approaches, including nanomedicine, biomaterials, immunotherapy, cell therapy, and gene therapy, which are emerging and likely to significantly impact CVD management in the coming decade. This review summarizes the current anti-atherosclerotic therapies' major milestones, strengths, and limitations. It provides an overview of the recent discoveries and emerging technologies in nanomedicine, cell therapy, and gene and immune therapeutics that can revolutionize CVD clinical practice by steering it toward precision medicine. CVD-related clinical trials and promising pre-clinical strategies that would significantly impact patients with CVD are discussed. Here, we review these recent advances, highlighting key clinical opportunities in the rapidly emerging field of CVD medicine.

Antimicrobial photodynamic therapy against Escherichia coli by exploiting endogenously produced Protoporphyrin IX- In vitro study

Due to antimicrobial drug resistance, there is a growing interest in the development of light based alternative antibacterial therapies. This research work is focused on the inactivation of Escherichia coli (E. coli) by exploiting the absorption bands 405, 505, 542, 580 and 631 nm of its indigenously produced Protoporphyrin IX (PpIX) excited by three LEDs with broad emission bands at 418, 522 and 630 nm and two laser diodes with narrow emission bands at 405 and 635 nm. Fluorescence spectroscopy and plate count method have been employed for studying the inactivation rate of E. coli strain in autoclaved water suspension. It has been found that LEDs at 418, 522 and 630 nm produced pronounced antimicrobial photodynamic effect on E. coli strain comparing laser diodes at 405 and 635 nm, which might be attributed to the overlapping of broad emission bands of LEDs with the absorption bands of PpIX than narrow emission bands of laser diodes. Particular effect of LED at 522 nm has been noticed because its broad emission band overlaps three absorption bands 505, 542 and 580 nm of PpIX. The gold standard plate count method strongly correlates with Fluorescence spectroscopy, making it an innovative tool to administer bacterial inactivation. The experimental results suggested the development of a light source that entirely overlap absorption bands of PpIx to produce a pronounced antimicrobial photodynamic effect, which might become an effective modality for in vivo disinfection of antibiotic resistant microbes in wounds and lesions.

Porphyrin Photosensitizers into Polysaccharide-Based Biopolymer Hydrogels for Topical Photodynamic Therapy: Physicochemical and Pharmacotechnical Assessments

Photodynamic therapy (PDT) is an emerging treatment modality that utilizes light-sensitive compounds, known as photosensitizers, to produce reactive oxygen species (ROS) that can selectively destroy malignant or diseased tissues upon light activation. This study investigates the incorporation of two porphyrin structures, 5-(4-hydroxy-3-methoxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.2.) and 5,10,15,20-tetrakis-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.1.), into hydroxypropyl cellulose (HPC) hydrogels for potential use in topical photodynamic therapy (PDT). The structural and compositional properties of the resulting hydrogels were characterized using advanced techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), UV-Visible (UV-Vis) spectroscopy, and fluorescence spectroscopy. FTIR spectra revealed a slight shift of the main characteristic absorption bands corresponding to the porphyrins and their interactions with the HPC matrix, indicating successful incorporation and potential hydrogen bonding. XRD patterns revealed the presence of crystalline domains within the HPC matrix, indicating partial crystallization of the porphyrins dispersed within the amorphous polymer structure. TGA results indicated enhanced thermal stability of the HPC-porphyrin gels compared to 10% HPC gel, with additional weight loss stages corresponding to the thermal degradation of the porphyrins. Rheological analysis showed that the gels exhibited pseudoplastic behavior and thixotropic properties, with minimal impact on the flow properties of HPC by P2.1., but notable changes in viscosity and shear stress with P2.2. incorporation, indicating structural modifications. AFM imaging revealed a homogeneous distribution of porphyrins, and UV-Vis and fluorescence spectroscopy confirmed the retention of their photophysical properties. Pharmacotechnical evaluations showed that the hydrogels possessed suitable mechanical properties, optimal pH, high swelling ratios, and excellent spreadability, making them ideal for topical application. These findings suggest that the porphyrin-incorporated HPC hydrogels have significant potential as effective therapeutic agents for topical applications.

Bactericidal Effect of Different Photochemical-Based Therapy Options on Implant Surfaces-An In Vitro Study

Objectives: Photochemical systems are frequently recommended as an adjuvant treatment option in peri-implantitis therapy. The aim of the present study was to evaluate the efficacy of these treatment options, as well as a novel curcumin-based option, in a biofilm model on implants. Methods: Eighty dental implants were inoculated with an artificial biofilm of periodontal pathogens and placed in peri-implant pocket models. The following groups were analyzed: I, photodynamic therapy (PDT); II, PDT dye; III, curcumin/DMSO + laser; IV, curcumin/DMSO only; V, dimethyl sulfoxide (DMSO) only; VI, photothermal therapy (PTT); VII, PTT dye; VIII, control. After treatment, remaining bacterial loads were assessed microbiologically using quantitative real-time polymerase chain reaction analysis. Results: The PDT, PTT, and DMSO treatment methods were associated with statistically significant (p < 0.05) improvements in germ reduction in comparison with the other methods and the untreated control group. The mean percentage reductions were as follows: I (PDT) 93.9%, II (PDT dye) 62.9%, III (curcumin/DMSO + laser) 74.8%, IV (curcumin/DMSO only) 67.9%, V (DMSO) 89.4%, VI (PTT) 86.8%, and VII (PTT dye) 66.3%. Conclusions: The commercially available PDT and PTT adjuvant treatment systems were associated with the largest statistically significant reduction in periopathogenic bacteria on implant surfaces. However, activation with laser light at a suitable wavelength is necessary to achieve the bactericidal effects. The use of curcumin as a photosensitizer for 445 nm laser irradiation did not lead to any improvement in antibacterial efficacy in comparison with rinsing with DMSO solution alone.