Current Challenges and Opportunities of Photodynamic Therapy against Cancer

Drug-Loaded Mitochondrial Targeted Nanoparticles for Tumor Imaging and PDT/PTT Combined Chemotherapy in Muscle-Invasive Bladder Cancer

Neoadjuvant chemotherapy combined with radical cystectomy is the standard treatment for muscle-invasive bladder cancer (MIBC). While cisplatin-based regimens reduce postoperative recurrence, their severe toxicity often limits clinical application. Moreover, the need for urinary diversion after radical cystectomy significantly impacts quality of life, leading to reluctance toward surgery. Therefore, developing tumor-targeted therapies and alternative treatment strategies for MIBC is of great clinical significance. In this study, the IR780 iodide multifunctional dye is conjugated to alginate polysaccharide and developed a novel cisplatin-loaded nanoparticle. Then, the tumor targeting and antitumor effects of the nanoparticles are evaluated in vitro and in vivo. The results show that the nanoparticles have sufficient drug loading, enhanced tumor targeting, and good photothermal effect. Furthermore, they shows potential for tumor imaging and diagnostic applications in a mouse model of MIBC. This study proposes a potentially effective treatment for MIBC by combining near-infrared localized phototherapy with systemic chemotherapy to eliminate malignant tissue.

Fighting Cancer with Photodynamic Therapy and Nanotechnologies: Current Challenges and Future Directions

Photodynamic therapy (PDT) is an innovative treatment that has recently been approved for clinical use and holds promise for cancer patients. It offers several benefits, such as low systemic toxicity, minimal invasiveness, and the ability to stimulate antitumor immune responses. For certain types of cancer, it has shown positive results with few side effects. However, PDT still faces some challenges, including limited light penetration into deeper tumor tissues, uneven distribution of the photosensitizer (PS) that can also affect healthy cells, and the difficulties posed by the hypoxic tumor microenvironment (TME). In hypoxic conditions, PDT's effectiveness is reduced due to insufficient production of reactive oxygen species, which limits tumor destruction and can lead to relapse. This review highlights recent advances in photosensitizers and nanotechnologies that are being developed to improve PDT. It focuses on multifunctional nanoplatforms and nanoshuttles that have shown promise in preclinical studies, especially for treating solid tumors. One of the key areas of focus is the development of PSs that specifically target mitochondria to treat deep-seated malignant tumors. New mitochondria-targeting nano-PSs are designed with better water solubility and extended wavelength ranges, allowing them to target tumors more effectively, even in challenging, hypoxic environments. These advancements in PDT are opening new doors for cancer treatment, especially when combined with other therapeutic strategies. Moving forward, research should focus on optimizing PDT, creating more efficient drug delivery systems, and developing smarter PDT platforms. Ultimately, these efforts aim to make PDT a first-choice treatment option for cancer patients.

The Combination of Active-Targeted Photodynamic Therapy and Photoactivated Chemotherapy for Enhanced Cancer Treatment

Scientists have been actively investigating novel therapies that can effectively eradicate cancer cells with negligible side effects in normal tissues when used alone or in a combinatorial approach. Photodynamic therapy has emerged as a promising non-invasive therapy that integrates photosensitizer, oxygen, and a specific wavelength of light for the treatment of cancer. Despite encouraging outcomes yielded by PDT, conventional PSs are faced with longstanding challenges such as poor water solubility, a short half-life, and off-target toxicity. Development of nanotherapeutics has shown great potential in overcoming this issue. The tumor microenvironment is inherently hypoxic, and this promotes tumor resistance to PDT, as it is oxygen-dependent. Photoactivated chemotherapy, an oxygen-independent light-based therapy, utilizes chemotherapeutic regimens that remain inert until exposed to light, allowing target-specific activation while minimizing off-target toxicity. Integration of these techniques can improve selectivity and yield synergistic cytotoxic effects that could improve cancer treatment.

Illuminating the path: the role of photodynamic therapy in comprehensive periodontal treatment

OBJECTIVES

Evaluating photodynamic therapy's efficacy and suitability for treating periodontal disease is the main goal of this review. What are the best conditions for using photodynamic therapy, and how can it improve conventional periodontal treatments?.

MATERIALS AND METHODS

A comprehensive literature search has been conducted to identify peer-reviewed research published up until August 2024. This search utilized reputable databases, including PubMed, Scopus, and Google Scholar, ensuring a robust selection of relevant studies. Selected studies were meticulously analyzed to their methodologies, types of photosensitizers employed, light intensity levels applied, as well as the resultant clinical outcomes observed. Additionally, a comparative analysis has been performed between photodynamic therapy and traditional periodontal therapy as documented in numerous clinical studies.

RESULTS

Results show that photodynamic therapy considerably lowers the number of microorganisms present in periodontal pockets, which in turn reduces inflammation and improves healing responses. According to studies, photodynamic therapy is an efficient way to break up the biofilms that of harmful bacteria that cause periodontal disease produce.

CONCLUSIONS

Photodynamic therapy is an intriguing alternative treatment option for periodontal disease. Because photodynamic therapy reduces biofilm resistance, improves blood flow, and promotes healing through anti-inflammatory effects, it may yield better clinical results when used in conjunction with conventional periodontal therapies. More research is required to create consistent guidelines for light dosage and photosensitizer selection in order to maximize therapeutic outcomes.

Advances in the Design of Photoactivatable Metallodrugs: Excited State Metallomics

Photoactivatable metal complexes offer the prospect of novel drugs with low side effects and new mechanisms of action to combat resistance to current therapy. We highlight recent progress in the design of platinum, ruthenium, iridium, gold and other transition metal complexes, especially for applications as anticancer and anti-infective agents. In particular, understanding excited state chemistry related to identification of the bioactive species (excited state metallomics/pharmacophores) is important. Photoactivatable metallodrugs are classified here as photocatalysts, photorelease agents and ligand-activated agents. Their activation wavelengths, cellular mechanisms of action, experimental and theoretical metallomics of excited states and photoproducts are discussed to explore new strategies for the design and investigation of photoactivatable metallodrugs. These photoactivatable metallodrugs have potential in clinical applications of Photodynamic Therapy (PDT), Photoactivated Chemotherapy (PACT) and Photothermal Therapy (PTT).

Nanobiohybrid Oncolytic Bacteria with Optimized Intratumoral Distribution for Combined Sono-Photodynamic/Immunotherapy

"Living therapeutic carriers" present a promising avenue for cancer research, but it is still challenging to achieve uniform and durable distribution of payloads throughout the solid tumor owing to the tumor microenvironment heterogeneity. Herein, a living drug sprinkle biohybrid (YB1-HCNs) was constructed by hitching acid/enzyme-triggered detachable nanoparticles (HCNs) backpack on the surface of metabolic oligosaccharide-engineered oncolytic bacteria YB1. Along with the process of tumor penetration by bacterial hypoxia navigation, YB1-HCNs responsively and continuously release HCNs, achieving a uniform distribution of loaded agents throughout the tumor. Upon successive irradiation of laser and ultrasound (US), the HCNs can separately generate type II and type I ROS for superior sono-photodynamic therapy (SPDT), which enables HCNs to synergize with YB1 for a satisfactory therapeutic effect in both superficial normoxic and deep hypoxic regions of the tumor. After a single dose, this efficient combination realized 98.3% primary tumor inhibition rate and prolonged survival of mice for 90 days with no recurrence, further inducing a powerful immunological memory effect to completely suppress tumor rechallenge in cured mice. Such a bacterial hybridization vector enables optimization of the spatial distribution of YB1 and HCNs, providing an innovative strategy to maximize therapeutic outcomes and evoke durable antitumor immunity.

Phase-Separated Spiropyran Coacervates as Dual-Wavelength-Switchable Reactive Oxygen Generators

Low-molecular-weight compounds of certain structural features may form coacervates through liquid-liquid phase separation (LLPS). These coacervates can enter mammalian cells and affect cellular physiology. Controlling the properties of the coacervates inside cells, however, is a challenge. Here, we report photochemical reactions of spiropyran (SP)-based coacervates with two wavelengths of light, in vitro, in the cell, and in animals, generating reactive oxygen species (ROS) for photo-controlled cell killing. We identify an SP-containing compound, SP-PEG8-SP, that forms coacervates (SP-C) in the aqueous solution. Photo illumination by a UV light triggers the isomerization of SP to merocyanine (MC), switching SP-C to the fluorescent coacervates MC-C. A visible light converts MC-C back to SP-C and induces ROS generation. Notably, coacervate formation increases the compound's ROS generation efficiency. The SP-C/MC-C coacervate system (collectively called spiropyran coacervates) can spontaneously enter cells, and a dual-wavelength-controlled reversible on/off switch and spatiotemporal-resolved ROS production is realized within the cytoplasm. Light-induced ROS generation leads to cytotoxicity to cancer cells, tumor organoids, and tumors in vivo, supporting spiropyran coacervates' potential use as coacervate photosensitizers in photodynamic therapies.

Hybrid Nanoplatforms Based on Photosensitizers and Metal/Covalent Organic Frameworks for Improved Cancer Synergistic Treatment Nano-Delivery Systems

Researchers have extensively investigated photosensitizer (PS) derivatives for various applications due to their superior photophysical and electrochemical properties. However, inherent problems, such as instability and self-quenching under physiological conditions, limit their biological applications. Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) represent two relatively new material types. These materials have high surface areas and permanent porosity, and they show a tremendous deal of potential for applications like these. This review summarizes key synthesis processes and highlights recent advancements in integrating PS-based COF and MOF nanocarriers for biomedical applications while addressing potential obstacles and prospects.

Enhancement of photoinduced reactive oxygen species generation in open-cage fullerenes

Photodynamic therapy is an important tool in modern medicine due to its effectiveness, safety, and the ability to provide targeted treatment for a range of diseases. Photodynamic therapy utilizes photosensitizers to generate reactive oxygen species (ROS). Fullerenes can be used as photosensitizers to produce ROS in high quantum yields. Open-cage fullerenes are a subclass of fullerenes characterized by a partially open structure, with one or more openings or apertures. The promising electrochemical properties of open-cage fullerenes motivated us to investigate their use for DNA-cleavage and ROS generation under visible light irradiation through type I electron transfer and type II energy transfer reactions. Our results show that open-cage C60 fullerenes are more efficient for photoinduced cleavage of DNA and ROS generation via both the type I electron transfer and type II energy transfer pathways than pristine C60 or a C60 pyrrolidine derivative without open-cage. The greater efficiency of ROS generation by open-cage C60 fullerene in type I and type II reactions can be attributed to the increased rate of the initial intersystem crossing process, resulting from larger total reorganization energies, as indicated by computationally calculated relative rates using the Marcus equation, and the lower reduction potential of the open-cage derivative 3, as determined by CV, which facilitates a more efficient generation of the corresponding radical anion (C60˙-).

Targeting ocular malignancies using a novel light-activated virus-like drug conjugate

Background

Targeted therapy is a promising approach to improve the treatment of tumors, including ocular malignancies. Current therapies, such as radiotherapy and surgery, often lead to serious damage to vision or to loss of the eye. New approaches have examined nanoparticles for use as targeted delivery vehicles for drugs. A newly-developed virus-like drug conjugate is a promising nanoparticle with a defined target: the novel virus-like particle-photosensitizer conjugate Belzupacap sarotalocan (Bel-sar, previous name AU-011).

Main text

In this review, we summarize the application of this novel light-activated virus-like particle conjugate in pre-clinical and clinical studies and discuss its potential to treat ocular malignancies, such as uveal melanoma and conjunctival melanoma. We furthermore discuss the combination with immunotherapy and its application on pigmented and non-pigmented tumors as well as its effect on macrophage polarization, which is important to achieve effective results in immunotherapy.

Conclusions

Belzupacap sarotalocan (Bel-sar) is a promising targeted drug carrier that enhances tumor-specific delivery and minimizes off-target effects. Its photodynamic therapy effectively treats pigmented and non-pigmented tumors while inducing immunogenic cell death through DAMP exposure, triggering local and systemic immune responses. Combining Bel-sar PDT with immunotherapy improves efficacy in preclinical models, warranting further clinical investigation.

Emerging nitric oxide gas-assisted cancer photothermal treatment

Photothermal therapy (PTT) has garnered significant attention in recent years, but the standalone application of PTT still faces limitations that hinder its ability to achieve optimal therapeutic outcomes. Nitric oxide (NO), being one of the most extensively studied gaseous molecules, presents itself as a promising complementary candidate for PTT. In response, various nanosystems have been developed to enable the simultaneous utilization of PTT and NO-mediated gas therapy (GT), with the integration of photothermal agents (PTAs) and thermally-sensitive NO donors being the prevailing approach. This combination seeks to leverage the synergistic effects of PTT and GT while mitigating the potential risks associated with gas toxicity through the use of a single laser irradiation. Furthermore, additional internal or external stimuli have been employed to trigger NO release when combined with different types of PTAs, thereby further enhancing therapeutic efficacy. This comprehensive review aims to summarize recent advancements in NO gas-assisted cancer photothermal treatment. It commences by providing an overview of various types of NO donors and precursors, including those sensitive to photothermal, light, ultrasound, reactive oxygen species, and glutathione. These NO donors and precursors are discussed in the context of dual-modal PTT/GT. Subsequently, the incorporation of other treatment modalities such as chemotherapy (CHT), photodynamic therapy (PDT), alkyl radical therapy, radiation therapy, and immunotherapy (IT) in the creation of triple-modal therapeutic nanoplatforms is presented. The review further explores tetra-modal therapies, such as PTT/GT/CHT/PDT, PTT/GT/CHT/chemodynamic therapy (CDT), PTT/GT/PDT/IT, PTT/GT/starvation therapy (ST)/IT, PTT/GT/Ca2+ overload/IT, PTT/GT/ferroptosis (FT)/IT, and PTT/GT/CDT/IT. Finally, potential challenges and future perspectives concerning these novel paradigms are discussed. This comprehensive review is anticipated to serve as a valuable resource for future studies focused on the development of innovative photothermal/NO-based cancer nanotheranostics.

Versatile Porphyrin Arrangements for Photodynamic Therapy-A Review

Nanotechnology is an emerging field that involves the development of nanoscale particles, their fabrication methods, and potential applications. From nanosized inorganic particles to biopolymers, the variety of nanoparticles is unstoppably growing, offering huge opportunities for drug delivery. Various nanoformulations, such as nanoparticles, nanocomposites, and nanoemulsions, have been developed to enhance drug stability, solubility, and tissue penetration. Moreover, nanocarriers can be specifically engineered to target diseased cells or release the drug in a controllable manner, minimizing damage to surrounding healthy tissues and reducing side effects. This review focuses on the combinations between porphyrin derivatives and nanocarriers applied in photodynamic therapy (PDT). PDT has emerged as a significant advance in medicine, offering a low-invasive method for managing infections, the treatment of tumors, and various dermatoses. The therapy relies on the activation of a photosensitizer by light, which results in the generation of reactive oxygen species. Despite their favorable properties, porphyrins reveal non-specific distribution within the body. Nanotechnology has the capability to enhance the PS delivery and its activation. This review explores the potential improvements that are provided by the use of nanotechnology in the PDT field.

Viral-Porphyrin Combo: Photodynamic and Oncolytic Viral Therapy for Potent Glioblastoma Treatment

Combined viral and photodynamic therapy for oncological diseases has great potential to treat aggressive tumors such as glioblastomas. A conjugate of vesicular stomatitis virus (VSV) with protoporphyrin IX was prepared, and its oncolytic effects were studied and compared to the effects of the individual components. The VSV showed an oncolytic effect on glioblastoma cell lines T98G and LN229 at a virus titer of 105 TCID50/mL. A VSV titer of 104 TCID50/mL was sufficient for neuroblastoma cell death. A study of the effect of VSV in tumor 3D cell modeling found that VSV had a clear viral cytopathic effect on spheroids of T98G and LN229 cells. Conjugation with the porphyrin significantly reduced the viral titer, but when irradiated, lysis of cells was observed. Photodynamic treatment of T98G and LN229 cells and spheroids with protoporphyrin IX as a photosensitizer also had a cytotoxic effect on cells and, to a lesser extent, on the tumoroids, as complete cell death was not achieved for the tumoroids. The combination therapy, which involved sequential photodynamic therapy using protoporphyrin IX as a photosensitizer and treatment with VSV, was shown to significantly enhance efficacy, resulting in complete cell death of both T98G and LN229 cells and tumoroids. The combination treatment allowed for the use of a lower viral titer (103-104 TCID50/mL) and a lower porphyrin concentration (0.5 μg/mL) to achieve a significant cytotoxic effect. As a result, the implementation of this combination therapy would likely lead to fewer side effects from the treatment. This study clearly demonstrated the excellent perspectives of combination therapy for the treatment of highly aggressive tumors such as glioblastomas.

Treatment of Conjunctival Melanoma Cell Lines With a Light-Activated Virus-Like Drug Conjugate Induces Immunogenic Cell Death

Purpose

Conjunctival melanoma (CJM) is a rare malignant ocular surface tumor, which often leads to local recurrences and metastases. In murine models of subcutaneous tumors, treatment with a novel virus-like drug conjugate (VDC; Bel-sar) showed a dual mechanism of action with direct tumor cell killing as well as stimulation of an antitumoral immune response. Bel-sar is currently being evaluated for the treatment of primary uveal melanoma and indeterminate nevi in a phase III clinical trial. We determined whether Bel-sar also has direct antitumor efficiency and a potential immunostimulatory capacity in CJM cells.

Methods

Three human tumor-derived CJM lines were used. Bel-sar's subcellular and intracellular locations were determined with tracers. Following light activation of Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were assessed. Treated tumor cells were co-cultured with THP-1 derived macrophages to assess tumor-cell phagocytosis.

Results

Bel-sar was bound and internalized by CJM cells and subsequently found in the cell membrane, lysosome, Golgi apparatus, and mitochondria. Bel-sar activation induced near complete cell death with half-maximal inhibitory concentration (IC50) values between 30 pM and 60 pM. Finally, light-activated Bel-sar enhanced exposure of DAMPs, including calreticulin, heat shock protein 90, and stimulated phagocytosis by macrophages.

Conclusions

Treatment with a novel VDC (Bel-sar) induced pro-immunogenic cell death in all three CJM cell lines. The in vitro cytotoxicity was accompanied by exposure of DAMPs, suggesting Bel-sar is a potential treatment for CJM by a dual mechanism of action. This dual mechanism may provide a targeted and direct killing of tumor cells and induce an immune response which might decrease local recurrences and metastasis.

Combining Photodynamic Therapy and Targeted Drug Delivery Systems: Enhancing Mitochondrial Toxicity for Improved Cancer Outcomes

Cancer treatment continues to be a substantial problem due to tumor complexities and persistence, demanding novel therapeutic techniques. This review investigates the synergistic potential of combining photodynamic therapy (PDT) and tailored medication delivery technologies to increase mitochondrial toxicity and improve cancer outcomes. PDT induces selective cellular damage and death by activating photosensitizers (PS) with certain wavelengths of light. However, PDT's efficacy can be hampered by issues such as poor light penetration and a lack of selectivity. To overcome these challenges, targeted drug delivery systems have emerged as a promising technique for precisely delivering therapeutic medicines to tumor cells while avoiding off-target effects. We investigate how these technologies can improve mitochondrial targeting and damage, which is critical for causing cancer cell death. The combination method seeks to capitalize on the advantages of both modalities: selective PDT activation and specific targeted drug delivery. We review current preclinical and clinical evidence supporting the efficacy of this combination therapy, focusing on case studies and experimental models. This review also addresses issues such as safety, distribution efficiency, resistance mechanisms, and costs. The prospects of further research include advances in photodynamic agents and medication delivery technology, with a focus on personalized treatment. In conclusion, combining PDT with targeted drug delivery systems provides a promising frontier in cancer therapy, with the ability to overcome current treatment limits and open the way for more effective, personalized cancer treatments.

Cold Atmospheric Plasma: Possible Cure of Autoimmune Disorders and Cancer via Attenuating Inflammation

Autoimmune diseases and cancers, two seemingly unrelated diseases, have been threatening human health, and many of them have no cure. By identifying pathological inflammation as the driving cause of uncontrolled cell proliferation in both classes of diseases, and differentiating autoimmune disorders and cancers by whether the cell death programs are under control, we propose the attenuation of prolonged inflammation via maintaining mitochondrial reduction-oxidation (redox) homeostasis being a possible cure of both diseases. Importantly, we propose the feasibility of applying cold atmospheric plasma (CAP) in treating autoimmune disorders and cancers given its redox-modulatory nature, which not only extends the medical utilities of CAP to autoimmune diseases and all other inflammation-driven disorders, but also positions the efficacy of CAP against cancer cells to its suppressive role on prolonged inflammation. Our insights may open an innovative avenue towards a unified view on the molecular mechanism driving the diversified types of medical miracles of CAP and what CAP can do in the field of plasma medicine.

Functional co-delivery nanoliposomes based on improving hypoxia for increasing photoimmunotherapy efficacy of cold tumors

Cold tumors lack T cells infiltration and have low immunogenicity, resulting insufficient immunotherapy response. Therefore, how to realize the transformation from cold tumor to hot tumor is an urgent problem to be solved. Photodynamic therapy can induce immunogenic death of tumor cells (ICD) and activate T lymphocytes to produce tumor immune response. However, hypoxia in the cold tumor microenvironment limits the effectiveness of photodynamic therapy. So in this article, MET-HMME/CAT-HMME@Nlip as a functional co-delivery nanoliposomes was constructed based on overcoming the above problems. Firstly, the oxygen-deficient state could be improved by the following two ways, one is catalase loaded in CAT-HMME@Nlip can decompose high concentration hydrogen peroxide to produce oxygen, and the other is metformin loaded in MET-HMME@Nlip can decrease oxygen consumption by inhibiting of mitochondrial respiration. And then with the increase of substrate oxygen concentration, the sensitivity of photodynamic therapy can be greatly improved and the anti-tumor immune response by PDT-induced ICD can also be enhanced obviously. In addition, metformin could act as a small molecule immune checkpoint inhibitor to reduce the expression of PD-L1 on the surface of tumor cells, thereby effectively improving the specific killing ability of cytotoxic T cells to tumor cells which could not only erasing the primary tumor, but also inhibiting the growth of simulated distant tumors through the immune memory function. This study provides a new idea for improving the clinical treatment effect of hypoxic cold tumors, especially for tumors that could not benefit from immunotherapy due to low or no expression of PD-L1 protein on the surface of tumor cells.

From (Sub)Porphyrins to (Sub)Phthalocyanines: Aromaticity Signatures in the UV-Vis Absorption Spectra

The development of novel synthetic methods has greatly expanded the toolbox available to chemists for engineering porphyrin and phthalocyanine derivatives with precise electronic and optical properties. In this study, we focus on the UV-vis absorption characteristics of substituted phthalocyanines and their contracted analogs, subphthalocyanines, which feature nonplanar, bowl-shaped geometries. These macrocycles, which are central to numerous applications in materials science and catalysis, possess extensive π-conjugated systems that drive their unique electronic properties. We explore how the change from a metalloid (B) to a metal (Zn) and the resulting coordination environments influence the aromaticity and, consequently, the spectroscopic features of these systems. A combined computational and experimental approach reveals a direct correlation between the aromaticity of the external conjugated pathways and the Q bands in the UV-vis spectra. Our findings highlight key structural modifications that can be leveraged to fine-tune the optical properties of porphyrinoid systems, offering new pathways for the design of advanced materials and catalysts with tailored functionalities.

To homeostasis and beyond! Recent advances in the medicinal chemistry of heterobifunctional derivatives

The field of induced proximity therapeutics has expanded dramatically over the past 3 years, and heterobifunctional derivatives continue to form a significant component of the activities in this field. Here, we review recent advances in the field from the perspective of the medicinal chemist, with a particular focus upon informative case studies, alongside a review of emerging topics such as Direct-To-Biology (D2B) methodology and utilities for heterobifunctional compounds beyond E3 ligase mediated degradation. We also include a critical evaluation of the latest thinking around the optimisation of physicochemical and pharmacokinetic attributes of these beyond Role of Five molecules, to deliver appropriate therapeutic exposure in vivo.

Inducing Immunogenic Cancer Cell Death through Oxygen-Economized Photodynamic Therapy with Nitric Oxide-Releasing Photosensitizers

Photodynamic therapy (PDT) utilizes reactive oxygen species (ROS) for eradication of cancer cells. Its effectiveness is governed by the oxygen content, which is scarce in the hypoxic tumor microenvironment. We report herein two zinc(II) phthalocyanines substituted with two or four nitric oxide (NO)-releasing moieties, namely ZnPc-2NO and ZnPc-4NO, which can suppress the mitochondrial respiration, thereby sparing more intracellular oxygen for PDT. Using HT29 human colorectal adenocarcinoma cells and A549 human lung carcinoma cells, we have demonstrated that both conjugates release NO upon interaction with the intracellular glutathione, which can reduce the cellular oxygen consumption rate and adenosine triphosphate generation and alter the mitochondrial membrane potential. They can also relieve the hypoxic status of cancer cells and decrease the expression of hypoxia-inducible factor protein HIF-1α. Upon light irradiation, both conjugates can generate ROS and induce cytotoxicity even under a hypoxic condition, overcoming the oxygen-dependent nature of PDT. Interestingly, the photodynamic action of ZnPc-2NO elicits the release of damage-associated molecular patterns, inducing the maturation of dendritic cells and triggering an antitumor immune response. The immunogenic cell death caused by this oxygen-economized PDT has been demonstrated through a series of in vitro and in vivo experiments.

Optimization of a Modular Nanotransporter Design for Targeted Intracellular Delivery of Photosensitizer

Modular nanotransporters (MNTs) are drug delivery systems for targeted cancer treatment. As MNTs are composed of several modules, they offer the advantage of high specificity and biocompatibility in delivering drugs to the target compartment of cancer cells. The large carrier module brings together functioning MNT modules and serves as a platform for drug attachment. The development of smaller-sized MNTs via truncation of the carrier module appears advantageous in facilitating tissue penetration. In this study, two new MNTs with a truncated carrier module containing either an N-terminal (MNTN) or a C-terminal (MNTC) part were developed by genetic engineering. Both new MNTs demonstrated a high affinity for target receptors, as revealed by fluorescent-labeled ligand-competitive binding. The liposome leakage assay proved the endosomolytic activity of MNTs. Binding to the importin heterodimer of each truncated MNT was revealed by a thermophoresis assay, while only MNTN possessed binding to Keap1. Finally, the photodynamic efficacy of the photosensitizer attached to MNTN was significantly higher than when attached to either MNTC or the original MNTs. Thus, this work reveals that MNT's carrier module can be truncated without losing MNT functionality, favoring the N-terminal part of the carrier module due to its ability to bind Keap1.

Insights on the Mechanical Properties of SARS-CoV-2 Particles and the Effects of the Photosensitizer Hypericin

SARS-CoV-2 is a highly pathogenic virus responsible for the COVID-19 disease. It belongs to the Coronaviridae family, characterized by a phospholipid envelope, which is crucial for viral entry and replication in host cells. Hypericin, a lipophilic, naturally occurring photosensitizer, was reported to effectively inactivate enveloped viruses, including SARS-CoV-2, upon light irradiation. In addition to its photodynamic activity, Hyp was found to exert an antiviral action also in the dark. This study explores the mechanical properties of heat-inactivated SARS-CoV-2 viral particles using Atomic Force Microscopy (AFM). Results reveal a flexible structure under external stress, potentially contributing to the virus pathogenicity. Although the fixation protocol causes damage to some particles, correlation with fluorescence demonstrates colocalization of partially degraded virions with their genome. The impact of hypericin on the mechanical properties of the virus was assessed and found particularly relevant in dark conditions. These preliminary results suggest that hypericin can affect the mechanical properties of the viral envelope, an effect that warrants further investigation in the context of antiviral therapies.

A meta-analysis and systematic review of photodynamic therapy for diabetic foot ulcers

BACKGROUND

Diabetic foot ulcer (DFU) is a chronic and challenging condition, addressed through various treatments including photodynamic therapy (PDT) and standard of care (SOC), yet lacking consensus on the optimal approach. This study presents a comprehensive meta-analysis of randomized controlled trials to evaluate the efficacy and safety of PDT versus SOC in managing DFU.

METHODS

An extensive literature search was conducted across PubMed, Embase, and the Cochrane Library databases to identify RCTs that compared the effectiveness of PDT with SOC in treating DFU. The primary metrics evaluated included changes in ulcer area, wound healing indices, and pain levels experienced by the patients.

RESULTS

This meta-analysis incorporated data from 6 RCTs, encompassing 458 patients with 467 DFUs. The analysis indicated that while PDT led to a faster reduction in ulcer size compared to SOC, the difference was not statistically significant [mean difference (MD): 2.73cm², 95 % Confidence Interval (CI) -2.98 to 8.44; p > 0.05]. However, a notable improvement was observed in the wound healing rate in the PDT group [MD: 29.26 %, 95 % CI 7.24 to 51.28; p = 0.01]. Based on the Visual Analog Scale (VAS), pain assessment revealed no significant difference between the two treatment groups [MD: 2.35, 95 % CI -2.36 to 7.06; p = 0.33].

CONCLUSION

The study suggests that PDT might offer an enhanced healing rate for DFUs compared to SOC alone, potentially leading to improved patient outcomes. Importantly, our findings highlight the superiority of photodynamic therapy in accelerating ulcer healing without an associated increase in complications.

PROSPERO

2023 CRD42023493930.

Spatiotemporal Release of Singlet Oxygen in Low Molecular Weight Organo-Gels Upon Thermal or Photochemical External Stimuli

The first example of a material capable of spatiotemporal catch and release of singlet oxygen (1O2) in gel phase is presented. Several low molecular weight organogelators based around an oxotriphenylhexanoate (OTHO) core are developed and optimized with regard to; their gelation properties, and ability of releasing 1O2 upon thermal and/or photochemical external stimuli, in both gel phase and solution. Remarkably, reversible phase transitioning between the gel and solution phase are also demonstrated. Taken together two complementary modes of releasing 1O2, one thermally controlled over time, and one rapid release by means of photochemical stimuli is disclosed. These findings represent the first phase reversible system where function and aggregation properties can be controlled independently, and thus pave the way for novel applications in material sciences as well as in life sciences.

Green synthesis and characterization of AgNPs, liposomal loaded AgNPs and ZnPcS4 photosensitizer for enhanced photodynamic therapy effects in MCF-7 breast cancer cells

Breast cancer remains a formidable challenge in oncology despite significant advancements in treatment modalities. Conventional therapies such as surgery, chemotherapy, radiation therapy, and hormonal therapy have been the mainstay in managing breast cancer for decades. However, a subset of patient's experiences treatment failure, leading to disease recurrence and progression. Therefore, this study investigates the therapeutic potential of green-synthesized silver nanoparticles (AgNPs) using an African medicinal plant (Dicoma anomala methanol root extract) as a reducing agent for combating breast cancer. AgNPs were synthesized using the bottom-up approach and later modified with liposomes (Lip) loaded with photosensitizer (PS) zinc phthalocyanine tetrasulfonate (Lip@ZnPcS4) using thin film hydration method. The successful formation and Lip modification of AgNPs, alongside ZnPcS4, were confirmed through various analytical techniques including UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Following a 24 h treatment period, MCF-7 cells were assessed for viability using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT viability assay), cell death analysis using mitochondrial membrane potential (MMP) (ΔΨm), Annexin V-fluorescein isothiocyanate (FITC)-propidium iodide (PI) kit, and caspase- 3, 8 and 9 activities. The experiments were repeated four times (n = 4), and the results were analyzed using SPSS statistical software version 27, with a confidence interval set at 0.95. The synthesized nanoparticles and nanocomplex, including AgNPs, AgNPs-Lip, Lip@ZnPcS4, and AgNPs-Lip@ZnPcS4, exhibited notable cytotoxicity and therapeutic efficacy against MCF-7 breast cancer cells. Notably, the induction of apoptosis, governed by the upregulation of apoptotic proteins i.e., caspase 8 and 9 activities. In addition, caspase 3 was not expressed by MCF-7 cells in both control and experimental groups. Given the challenging prognosis associated with breast cancer, the findings underscore the promise of liposomal nanoformulations in cancer photodynamic therapy (PDT), thus warranting further exploration in clinical settings.

Recent Progress in Thermally Activated Delayed Fluorescence Photosensitizers for Photodynamic Therapy

Photodynamic therapy (PDT) is a rapidly growing discipline that is expected to become an encouraging noninvasive therapeutic strategy for cancer treatment. In the PDT process, an efficient intersystem crossing (ISC) process for photosensitizers from the singlet excited state (S1) to the triplet excited state (T1) is critical for the formation of cytotoxic reactive oxygen species and improvement of PDT performance. Thermally activated delayed fluorescence (TADF) molecules featuring an extremely small singlet-triplet energy gap and an efficient ISC process represent an enormous breakthrough for the PDT process. Consequently, the development of advanced TADF photosensitizers has become increasingly crucial and pressing. The most recent developments in TADF photosensitizers aimed at enhancing PDT efficiency for bio-applications are presented in this review. TADF photosensitizers with water dispersibility, targeting ability, activatable ability, and two-photon excitation properties are highlighted. Furthermore, the future challenges and perspectives of TADF photosensitizers in PDT are proposed.

Recent Advances in Photodynamic Therapy: Metal-Based Nanoparticles as Tools to Improve Cancer Therapy

Cancer remains a significant global health challenge, with traditional therapies like surgery, chemotherapy, and radiation often accompanied by systemic toxicity and damage to healthy tissues. Despite progress in treatment, these approaches have limitations such as non-specific targeting, systemic toxicity, and resistance development in cancer cells. In recent years, nanotechnology has emerged as a revolutionary frontier in cancer therapy, offering potential solutions to these challenges. Nanoparticles, due to their unique physical and chemical properties, can carry therapeutic payloads, navigate biological barriers, and selectively target cancer cells. Metal-based nanoparticles, in particular, offer unique properties suitable for various therapeutic applications. Recent advancements have focused on the integration of metal-based nanoparticles to enhance the efficacy and precision of photodynamic therapy. Integrating nanotechnology into cancer therapy represents a paradigm shift, enabling the development of strategies with enhanced specificity and reduced off-target effects. This review aims to provide a comprehensive understanding of the pivotal role of metal-based nanoparticles in photodynamic therapy. We explore the mechanisms, biocompatibility, and applications of metal-based nanoparticles in photodynamic therapy, highlighting the challenges and the limitations in their use, as well as the combining of metal-based nanoparticles/photodynamic therapy with other strategies as a synergistic therapeutic approach for cancer treatment.

Photodynamic Therapy in the Treatment of Cancer-The Selection of Synthetic Photosensitizers

Photodynamic therapy (PDT) is a promising cancer treatment method that uses photosensitizing (PS) compounds to selectively destroy tumor cells using laser light. This review discusses the main advantages of PDT, such as its low invasiveness, minimal systemic toxicity and low risk of complications. Special attention is paid to photosensitizers obtained by chemical synthesis. Three generations of photosensitizers are presented, starting with the first, based on porphyrins, through the second generation, including modified porphyrins, chlorins, 5-aminolevulinic acid (ALA) and its derivative hexyl aminolevulinate (HAL), to the third generation, which is based on the use of nanotechnology to increase the selectivity of therapy. In addition, current research trends are highlighted, including the search for new photosensitizers that can overcome the limitations of existing therapies, such as heavy-atom-free nonporphyrinoid photosensitizers, antibody-drug conjugates (ADCs) or photosensitizers with a near-infrared (NIR) absorption peak. Finally, the prospects for the development of PDTs are presented, taking into account advances in nanotechnology and biomedical engineering. The references include both older and newer works. In many cases, when writing about a given group of first- or second-generation photosensitizers, older publications are used because the properties of the compounds described therein have not changed over the years. Moreover, older articles provide information that serves as an introduction to a given group of drugs.

Advances in antitumor application of ROS enzyme-mimetic catalysts

The rapid growth of research on enzyme-mimetic catalysts (Enz-Cats) is expected to promote further advances in nanomedicine for biological detection, diagnosis and treatment of disease, especially tumors. ROS-based nanomedicines present fascinating potential in antitumor therapy owing to the rapid development of nanotechnology. In this review, we focus on the applications of Enz-Cats based on ROS in antitumor therapy. Firstly, the definition and category of ROS are introduced, and the key factors enhancing ROS levels are carefully elucidated. Then, the rationally engineered Enz-Cats via different synthetic approaches with high ROS-producing efficiencies are comprehensively discussed. Subsequently, oncotherapy application of Enz-Cats is comprehensively discussed, which integrates diverse synergistic treatment modalities and exhibits high efficiency in ROS generation. Finally, the challenges and future research direction of this field are presented. This review is dedicated to unraveling the enigmas surrounding the interplay of nanomedicine and organisms.

Hypericin-mediated photodynamic therapy inhibits metastasis and EMT of colorectal cancer cells by regulating RhoA-ROCK1 signaling pathway

Colorectal cancer (CRC) is significantly contributed to global cancer mortality rates. Treating CRC is particularly challenging due to metastasis and drug resistance. There is a pressing need for new treatment strategies against metastatic CRC. Photodynamic therapy (PDT) offers a well-established, minimally invasive treatment option for cancer with limited side effects. Hypericin (HYP), a potent photosensitizer for PDT, has been documented to induce cytotoxicity and apoptosis in various types of cancers. However, there are few reports on the inhibitory effects of HYP-mediated PDT on the metastatic ability of CRC cells. Here, we evaluate the inhibitory effects of HYP-mediated PDT against metastatic CRC cells and define its underlying mechanisms. Wound-healing and Transwell assays show that HYP-mediated PDT suppresses migration and invasion of CRC cells. F-actin visualization assays indicate HYP-mediated PDT decreases F-actin formation in CRC cells. TEM assays reveal HYP-mediated PDT disrupts pseudopodia formation of CRC cells. Mechanistically, immunofluorescence and western blotting results show that HYP-mediated PDT upregulates E-cadherin and downregulates N-cadherin and Vimentin. HYP-mediated PDT also suppresses key EMT regulators, including Snail, MMP9, ZEB1 and α-SMA. Additionally, the expressions of RhoA and ROCK1 are downregulated by HYP-mediated PDT. Together, these findings suggest that HYP-mediated PDT inhibits the migration and invasion of HCT116 and SW620 cells by modulating EMT and RhoA-ROCK1 signaling pathway. Thus, HYP-mediated PDT presents a potential therapeutic option for CRC.

Photodynamic therapy for cancer: mechanisms, photosensitizers, nanocarriers, and clinical studies

Photodynamic therapy (PDT) is a temporally and spatially precisely controllable, noninvasive, and potentially highly efficient method of phototherapy. The three components of PDT primarily include photosensitizers, oxygen, and light. PDT employs specific wavelengths of light to active photosensitizers at the tumor site, generating reactive oxygen species that are fatal to tumor cells. Nevertheless, traditional photosensitizers have disadvantages such as poor water solubility, severe oxygen-dependency, and low targetability, and the light is difficult to penetrate the deep tumor tissue, which remains the toughest task in the application of PDT in the clinic. Here, we systematically summarize the development and the molecular mechanisms of photosensitizers, and the challenges of PDT in tumor management, highlighting the advantages of nanocarriers-based PDT against cancer. The development of third generation photosensitizers has opened up new horizons in PDT, and the cooperation between nanocarriers and PDT has attained satisfactory achievements. Finally, the clinical studies of PDT are discussed. Overall, we present an overview and our perspective of PDT in the field of tumor management, and we believe this work will provide a new insight into tumor-based PDT.

Dual regulation of osteosarcoma hypoxia microenvironment by a bioinspired oxygen nanogenerator for precise single-laser synergistic photodynamic/photothermal/induced antitumor immunity therapy

The hypoxic tumor microenvironment (TME) of osteosarcoma (OS) is the Achilles' heel of oxygen-dependent photodynamic therapy (PDT), and tremendous challenges are confronted to reverse the hypoxia. Herein, we proposed a "reducing expenditure of O2 and broadening sources" dual-strategy and constructed ultrasmall IrO2@BSA-ATO nanogenerators (NGs) for decreasing the O2-consumption and elevating the O2-supply simultaneously. As O2 NGs, the intrinsic catalase (CAT) activity could precisely decompose the overexpressed H2O2 to produce O2 in situ, enabling exogenous O2 infusion. Moreover, the cell respiration inhibitor atovaquone (ATO) would be at the tumor sites, effectively inhibiting cell respiration and elevating oxygen content for endogenous O2 conservation. As a result, IrO2@BSA-ATO NGs systematically increase tumor oxygenation in dual ways and significantly enhance the antitumor efficacy of PDT. Moreover, the extraordinary photothermal conversion efficiency allows the implementation of precise photothermal therapy (PTT) under photoacoustic guidance. Upon a single laser irradiation, this synergistic PDT, PTT, and the following immunosuppression regulation performance of IrO2@BSA-ATO NGs achieved a superior tumor cooperative eradicating capability both in vitro and in vivo. Taken together, this study proposes an innovative dual-strategy to address the serious hypoxia problem, and this microenvironment-regulable IrO2@BSA-ATO NGs as a multifunctional theranostics platform shows great potential for OS therapy.

Deep Learning Insights into the Dynamic Effects of Photodynamic Therapy on Cancer Cells

Photodynamic therapy (PDT) shows promise in tumor treatment, particularly when combined with nanotechnology. This study examines the impact of deep learning, particularly the Cellpose algorithm, on the comprehension of cancer cell responses to PDT. The Cellpose algorithm enables robust morphological analysis of cancer cells, while logistic growth modelling predicts cellular behavior post-PDT. Rigorous model validation ensures the accuracy of the findings. Cellpose demonstrates significant morphological changes after PDT, affecting cellular proliferation and survival. The reliability of the findings is confirmed by model validation. This deep learning tool enhances our understanding of cancer cell dynamics after PDT. Advanced analytical techniques, such as morphological analysis and growth modeling, provide insights into the effects of PDT on hepatocellular carcinoma (HCC) cells, which could potentially improve cancer treatment efficacy. In summary, the research examines the role of deep learning in optimizing PDT parameters to personalize oncology treatment and improve efficacy.

Photodynamic Therapy with Targeted Release of Boron-Dipyrromethene Dye from Cobalt(III) Prodrugs in Red Light

Boron-dipyrromethene (BODIPY) dyes are promising photosensitizers for cellular imaging and photodynamic therapy (PDT) owing to their excellent photophysical properties and the synthetically tunable core. Metalation provides a convenient way to overcome the drawbacks arising from their low aqueous solubility. New photo-/redox-responsive Co(III) prodrug chaperones are developed as anticancer PDT agents for efficient cellular delivery of red-light-active BODIPY dyes. The photobiological activity of heteroleptic Co(III) complexes derived from tris(2-pyridylmethyl)amine (TPA) and acetylacetone-conjugated PEGylated distyryl BODIPY (HL1) or its dibromo analogue (HL2), [CoIII(TPA)(L1/L2)](ClO4)2 (1 and 2), are investigated. The Co(III)/Co(II) redox potential is tuned using the Co(III)-TPA scaffold. Complex 1 displays the in vitro release of BODIPY on red light irradiation. Complex 2, having good singlet oxygen quantum yield (ΦΔ ∼ 0.28 in DMSO), demonstrates submicromolar photocytotoxicity to HeLa cancer cells (IC50 ≈ 0.23 μM) while being less toxic to HPL1D normal cells in red light. Cellular imaging using the emissive complex 1 shows mitochondrial localization and significant penetration into the HeLa tumor spheroids. Complex 2 shows supercoiled DNA photocleavage activity and apoptotic cell death through phototriggered generation of reactive oxygen species. The Co(III)-BODIPY prodrug conjugates exemplify new type of phototherapeutic agents with better efficacy than the organic dyes alone in the phototherapeutic window.

Enhancing cancer immunotherapy with photodynamic therapy and nanoparticle: making tumor microenvironment hotter to make immunotherapeutic work better

Cancer immunotherapy has made tremendous advancements in treating various malignancies. The biggest hurdle to successful immunotherapy would be the immunosuppressive tumor microenvironment (TME) and low immunogenicity of cancer cells. To make immunotherapy successful, the 'cold' TME must be converted to 'hot' immunostimulatory status to activate residual host immune responses. To this end, the immunosuppressive equilibrium in TME should be broken, and immunogenic cancer cell death ought to be induced to stimulate tumor-killing immune cells appropriately. Photodynamic therapy (PDT) is an efficient way of inducing immunogenic cell death (ICD) of cancer cells and disrupting immune-restrictive tumor tissues. PDT would trigger a chain reaction that would make the TME 'hot' and have ICD-induced tumor antigens presented to immune cells. In principle, the strategic combination of PDT and immunotherapy would synergize to enhance therapeutic outcomes in many intractable tumors. Novel technologies employing nanocarriers were developed to deliver photosensitizers and immunotherapeutic to TME efficiently. New-generation nanomedicines have been developed for PDT immunotherapy in recent years, which will accelerate clinical applications.

Monitoring of singlet oxygen generation of a novel Schiff-base substituted silicon phthalocyanines by sono-photochemical studies and in vitro activities on prostate cancer cell

This study demonstrates the potential of sono-photodynamic therapy as an effective approach for enhancing singlet oxygen generation using the synthesized Schiff-base diaxially substituted silicon phthalocyanines. In photochemical studies, the singlet oxygen quantum yields (Φ∆) were determined as 0.43 for Si1a, 0.94 for Q-Si1a, 0.58 for S-Si1a, and 0.49 for B-Sia1. In sono-photochemical studies, the Φ∆ values were reached to 0.67 for Si1a, 1.06 for Q-Si1a, 0.65 for S-Si1a, and 0.67 for B-Sia1. In addition, this study demonstrates the therapeutic efficacy of phthalocyanines synthesized as sensitizers on the PC3 prostate cancer cell line through in vitro experiments. The application of these treatment modalities exhibited notable outcomes, leading to a substantial decrease in cell viability within the PC3 prostate cancer cell line. These findings highlight the potential of utilizing these synthesized phthalocyanines as promising therapeutic agents for prostate cancer treatment.

Recent Advances in Reprogramming Strategy of Tumor Microenvironment for Rejuvenating Photosensitizers-Mediated Photodynamic Therapy

Photodynamic therapy (PDT) has recently been considered a potential tumor therapy due to its time-space specificity and non-invasive advantages. PDT can not only directly kill tumor cells by using cytotoxic reactive oxygen species but also induce an anti-tumor immune response by causing immunogenic cell death of tumor cells. Although it exhibits a promising prospect in treating tumors, there are still many problems to be solved in its practical application. Tumor hypoxia and immunosuppressive microenvironment seriously affect the efficacy of PDT. The hypoxic and immunosuppressive microenvironment is mainly due to the abnormal vascular matrix around the tumor, its abnormal metabolism, and the influence of various immunosuppressive-related cells and their expressed molecules. Thus, reprogramming the tumor microenvironment (TME) is of great significance for rejuvenating PDT. This article reviews the latest strategies for rejuvenating PDT, from regulating tumor vascular matrix, interfering with tumor cell metabolism, and reprogramming immunosuppressive related cells and factors to reverse tumor hypoxia and immunosuppressive microenvironment. These strategies provide valuable information for a better understanding of the significance of TME in PDT and also guide the development of the next-generation multifunctional nanoplatforms for PDT.

A Bioorthogonal Antidote Against the Photosensitivity after Photodynamic Therapy

As an effective and non-invasive treatment modality for cancer, photodynamic therapy (PDT) has attracted considerable interest. With the recent advances in the photosensitizing agents, the fiber-optic systems, and other aspects, its application is extended to a wide range of superficial and localized cancers. However, for the few clinically used photosensitizers, most of them suffer from the drawback of causing prolonged photosensitivity after the treatment. As a result, post-PDT management is also a crucial issue. Herein, a facile bioorthogonal approach is reported that can effectively suppress this common side effect of PDT in nude mice. It involves the use of an antidote that contains a black-hole quencher BHQ-3 conjugated with a bicyclo[6.1.0]non-4-yne (BCN) moiety and a tetrazine-substituted boron dipyrromethene-based photosensitizer. By using tumor-bearing nude mice as an animal model, it is demonstrated that after PDT with this photosensitizer, the administration of the antidote can effectively quench the photodynamic activity of the residual photosensitizer by bringing the BHQ-3 quencher close to the photosensitizing unit through a rapid click reaction. It results in substantial reduction in skin damage upon light irradiation. The overall results demonstrate that this simple and facile strategy can provide an effective means for minimizing the photosensitivity after PDT.

Current Photodynamic Therapy for Glioma Treatment: An Update

Research on the development of photodynamic therapy for the treatment of brain tumors has shown promise in the treatment of this highly aggressive form of brain cancer. Analysis of both in vivo studies and clinical studies shows that photodynamic therapy can provide significant benefits, such as an improved median rate of survival. The use of photodynamic therapy is characterized by relatively few side effects, which is a significant advantage compared to conventional treatment methods such as often-used brain tumor surgery, advanced radiotherapy, and classic chemotherapy. Continued research in this area could bring significant advances, influencing future standards of treatment for this difficult and deadly disease.

Topical 5-aminolevulinic acid photodynamic therapy for recalcitrant facial flat warts

Photodynamic therapy (PDT) uses light energy to excite a photosensitizing agent, leading to production of reactive oxygen species, which exert cytotoxic effects on targeted cells. PDT has emerged as a promising therapeutic modality for the treatment of flat warts caused by human papillomavirus (HPV) infection, by targeting infected keratinocytes and inactivating nonenveloped viral particles. Some patients with recalcitrant flat warts on the face who have poor response to traditional treatment often seek effective therapy to have the warts removed. In this report, we retrospectively evaluated the efficacy of topical 10% 5-aminolevulinic acid PDT (ALA-PDT) in the treatment of 15 patients with recalcitrant facial flat warts. Patients received treatment once every two weeks for a total of two or three sessions. At 24 weeks after the start of treatment, 86.67% of patients showed complete or excellent response. Further more, the remission rate of 100% lesion clearance was 46.67% (seven patients), and the remission rate of 70-100% lesion clearance was 40.00% (six patients). None of the patients experienced disease recurrence or progression. The adverse reactions were generally well tolerated by the patients and mostly resolved in a few days without special treatment. Our findings showed that topical 10% ALA-PDT is a safe and effective treatment for recalcitrant facial flat warts.

Hybrid heterogeneous phantoms for biomedical applications: a demonstration to dosimetry validation

Phantoms simultaneously mimicking anatomical and optical properties of real tissues can play a pivotal role for improving dosimetry algorithms. The aim of the paper is to design and develop a hybrid phantom model that builds up on the strengths of solid and liquid phantoms for mimicking various anatomical structures for prostate cancer photodynamic therapy (PDT) dosimetry validation. The model comprises of a photosensitizer-embedded gelatin lesion within a liquid Intralipid prostate shape that is surrounded by a solid silicone outer shell. The hybrid phantom was well characterized for optical properties. The final assembled phantom was also evaluated for fluorescence tomographic reconstruction in conjunction with SpectraCure's IDOSE software. The developed model can lead to advancements in dosimetric evaluations. This would improve PDT outlook as a clinical treatment modality and boost phantom based standardization of biophotonic devices globally.

Photoacid Generators for Biomedical Applications

Photoacid generators (PAGs) are compounds capable of producing hydrogen protons (H+ ) upon irradiation, including irreversible and reversible PAGs, which have been widely studied in photoinduced polymerization and degradation for a long time. In recent years, the applications of PAGs in the biomedical field have attracted more attention due to their promising clinical value. So, an increasing number of novel PAGs have been reported. In this review, the recent progresses of PAGs for biomedical applications is systematically summarized, including tumor treatment, antibacterial treatment, regulation of protein folding and unfolding, control of drug release and so on. Furthermore, a concept of water-dependent reversible photoacid (W-RPA) and its antitumor effect are highlighted. Eventually, the challenges of PAGs for clinical applications are discussed.

Current Advances in Photodynamic Therapy (PDT) and the Future Potential of PDT-Combinatorial Cancer Therapies

Photodynamic therapy (PDT) is a two-stage treatment that implies the use of light energy, oxygen, and light-activated compounds (photosensitizers) to elicit cancerous and precancerous cell death after light activation (phototoxicity). The biophysical, bioengineering aspects and its combinations with other strategies are highlighted in this review, both conceptually and as they are currently applied clinically. We further explore the recent advancements of PDT with the use of nanotechnology, including quantum dots as innovative photosensitizers or energy donors as well as the combination of PDT with radiotherapy and immunotherapy as future promising cancer treatments. Finally, we emphasize the potential significance of organoids as physiologically relevant models for PDT.

Detection and Elimination of Senescent Cells with a Self-Assembled Senescence-Associated β-Galactosidase-Activatable Nanophotosensitizer

Senescent cells have become an important therapeutic target for many age-related dysfunctions and diseases. We report herein a novel nanophotosensitizing system that is responsive to the senescence-associated β-galactosidase (β-gal) for selective detection and elimination of these cells. It involves a dimeric zinc(II) phthalocyanine linked to a β-galactose unit via a self-immolative linker. This compound can self-assemble in aqueous media, forming stable nanoscale particles in which the phthalocyanine units are stacked and self-quenched for fluorescence emission and singlet oxygen production. Upon internalization into senescent HeLa cells, these nanoparticles interact with the overproduced senescence-associated β-gal inside the cells to trigger the disassembly process through enzymatic cleavage of the glycosidic bonds, followed by self-immolation to release the photoactive monomeric phthalocyanine units. These senescent cells can then be lit up with fluorescence and eliminated through the photodynamic action upon light irradiation with a half-maximal inhibitory concentration of 0.06 μM.

Metal-based nanoparticles in cancer therapy: Exploring photodynamic therapy and its interplay with regulated cell death pathways

Photodynamic therapy (PDT) represents a non-invasive treatment strategy currently utilized in the clinical management of selected cancers and infections. This technique is predicated on the administration of a photosensitizer (PS) and subsequent irradiation with light of specific wavelengths, thereby generating reactive oxygen species (ROS) within targeted cells. The cellular effects of PDT are dependent on both the localization of the PS and the severity of ROS challenge, potentially leading to the stimulation of various cell death modalities. For many years, the concept of regulated cell death (RCD) triggered by photodynamic reactions predominantly encompassed apoptosis, necrosis, and autophagy. However, in recent decades, further explorations have unveiled additional cell death modalities, such as necroptosis, ferroptosis, cuproptosis, pyroptosis, parthanatos, and immunogenic cell death (ICD), which helps to achieve tumor cell elimination. Recently, nanoparticles (NPs) have demonstrated substantial advantages over traditional PSs and become important components of PDT, due to their improved physicochemical properties, such as enhanced solubility and superior specificity for targeted cells. This review aims to summarize recent advancements in the applications of different metal-based NPs as PSs or delivery systems for optimized PDT in cancer treatment. Furthermore, it mechanistically highlights the contribution of RCD pathways during PDT with metal NPs and how these forms of cell death can improve specific PDT regimens in cancer therapy.

Tumor Pigmentation Does Not Affect Light-Activated Belzupacap Sarotalocan Treatment but Influences Macrophage Polarization in a Murine Melanoma Model

Purpose

Pigmentation in uveal melanoma is associated with increased malignancy and is known as a barrier for photodynamic therapy. We investigated the role of pigmentation in tumor behavior and the response to light-activated Belzupacap sarotalocan (Bel-sar) treatment in a pigmented (wild type) and nonpigmented (tyrosinase knock-out [TYR knock-out]) cell line in vitro and in a murine model.

Methods

The B16F10 (TYR knock-out) was developed using CRISPR/Cas9. After the treatment with light-activated Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were measured by flow cytometry. Treated tumor cells were co-cultured with bone marrow-derived macrophages (BMDMs) and dendritic cells (DCs) to assess phagocytosis and activation. Both cell lines were injected subcutaneously in syngeneic C57BL/6 mice.

Results

Knock-out of the tyrosinase gene in B16F10 led to loss of pigmentation and immature melanosomes. Pigmented tumors contained more M1 and fewer M2 macrophages compared with amelanotic tumors. Bel-sar treatment induced near complete cell death, accompanied with enhanced exposure of DAMPs in both cell lines, resulting in enhanced phagocytosis of BMDMs and maturation of DCs. Bel-sar treatment induced a shift to M1 macrophages and delayed tumor growth in both in vivo tumor models. Following treatment, especially the pigmented tumors and their draining lymph nodes contained IFN-gamma positive CD8+T cells.

Conclusions

Pigmentation influenced the type of infiltrating macrophages in the tumor, with more M1 macrophages in pigmented tumors. Belzupacap sarotalocan treatment induced immunogenic cell death and tumor growth delay in pigmented as well as in nonpigmented models and stimulated M1 macrophage influx in both models.

Overcoming challenges in cancer treatment: Nano-enabled photodynamic therapy as a viable solution

Cancer presents a formidable challenge, necessitating innovative therapies that maximize effectiveness while minimizing harm to healthy tissues. Nanotechnology has emerged as a transformative force in cancer treatment, particularly through nano-enabled photodynamic therapy (NE-PDT), which leverages precise and targeted interventions. NE-PDT capitalizes on photosensitizers activated by light to generate reactive oxygen species (ROS) that initiate apoptotic pathways in cancer cells. Nanoparticle enhancements optimize this process, improving drug delivery, selectivity, and ROS production within tumors. This review dissects NE-PDT's mechanistic framework, showcasing its potential to harness apoptosis as a potent tool in cancer therapy. Furthermore, the review explores the synergy between NE-PDT and complementary treatments like chemotherapy, immunotherapy, and targeted therapies, highlighting the potential to amplify apoptotic responses, enhance immune recognition of cancer cells, and inhibit resistance mechanisms. Preclinical and clinical advancements in NE-PDT demonstrate its efficacy across various cancer types. Challenges in translating NE-PDT into clinical practice are also addressed, emphasizing the need for optimizing nanoparticle design, refining dosimetry, and ensuring long-term safety. Ultimately, NE-PDT represents a promising approach in cancer therapy, utilizing the intricate mechanisms of apoptosis to address therapeutic hurdles. The review underscores the importance of understanding the interplay between nanoparticles, ROS generation, and apoptotic pathways, contributing to a deeper comprehension of cancer biology and novel therapeutic strategies. As interdisciplinary collaborations continue to thrive, NE-PDT offers hope for effective and targeted cancer interventions, where apoptosis manipulation becomes central to conquering cancer. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Photodynamic Therapy and Immunological View in Gastrointestinal Tumors

Gastrointestinal cancers are a specific group of oncological diseases in which the location and nature of growth are of key importance for clinical symptoms and prognosis. At the same time, as research shows, they pose a serious threat to a patient's life, especially at an advanced stage of development. The type of therapy used depends on the anatomical location of the cancer, its type, and the degree of progression. One of the modern forms of therapy used to treat gastrointestinal cancers is PDT, which has been approved for the treatment of esophageal cancer in the United States. Despite the increasingly rapid clinical use of this treatment method, the exact immunological mechanisms it induces in cancer cells has not yet been fully elucidated. This article presents a review of the current understanding of the mode of action of photodynamic therapy on cells of various gastrointestinal cancers with an emphasis on colorectal cancer. The types of cell death induced by PDT include apoptosis, necrosis, and pyroptosis. Anticancer effects are also a result of the destruction of tumor vasculature and activation of the immune system. Many reports exist that concern the mechanism of apoptosis induction, of which the mitochondrial pathway is most often emphasized. Photodynamic therapy may also have a beneficial effect on such aspects of cancer as the ability to develop metastases or contribute to reducing resistance to known pharmacological agents.

Progress of cell membrane-derived biomimetic nanovesicles for cancer phototherapy

In recent years, considerable attention has been given to phototherapy, including photothermal and photodynamic therapy to kill tumor cells by producing heat or reactive oxygen species (ROS). It has the high merits of noninvasiveness and limited drug resistance. To fully utilize this therapy, an extraordinary nanovehicle is required to target phototherapeutic agents in the tumor cells. Nanovesicles embody an ideal strategy for drug delivery applications. Cell membrane-derived biomimetic nanovesicles represent a developing type of nanocarrier. Combining this technique with cancer phototherapy could enable a novel strategy. Herein, efforts are made to describe a comprehensive overview of cell membrane-derived biomimetic nanovesicles for cancer phototherapy. The description in this review is mainly based on representative examples of exosome-derived biomimetic nanomedicine research, ranging from their comparison with traditional nanocarriers to extensive applications in cancer phototherapy. Additionally, the challenges and future prospectives for translating these for clinical application are discussed.

Recent advancement of nanomedicine-based targeted delivery for cervical cancer treatment

Cervical cancer is a huge worldwide health burden, impacting women in impoverished nations in particular. Traditional therapeutic approaches, such as surgery, radiation therapy, and chemotherapy, frequently result in systemic toxicity and ineffectiveness. Nanomedicine has emerged as a viable strategy for targeted delivery of therapeutic drugs to cancer cells while decreasing off-target effects and increasing treatment success in recent years. Nanomedicine for cervical cancer introduces several novel aspects that distinguish it from previous treatment options such as tailored delivery system, precision targeting, combination therapies, real-time monitoring and diverse nanocarriers to overcome the limitations of one another. This abstract presents recent advances in nanomedicine-based tailored delivery systems for the treatment of cervical cancer. Liposomes, polymeric nanoparticles, dendrimers, and carbon nanotubes have all been intensively studied for their ability to transport chemotherapeutic medicines, nucleic acids, and imaging agents to cervical cancer cells. Because of the way these nanocarriers are designed, they may cross biological barriers and preferentially aggregate at the tumor site, boosting medicine concentration and lowering negative effects on healthy tissues. Surface modification of nanocarriers with targeting ligands like antibodies, peptides, or aptamers improves specificity for cancer cells by identifying overexpressed receptors or antigens on the tumor surface. Furthermore, nanomedicine-based techniques have made it possible to co-deliver numerous therapeutic drugs, allowing for synergistic effects and overcoming drug resistance. In preclinical and clinical investigations, combination treatments comprising chemotherapeutic medicines, gene therapy, immunotherapy, and photodynamic therapy have showed encouraging results, opening up new avenues for individualized and multimodal treatment regimens. Furthermore, the inclusion of contrast agents and imaging probes into nanocarrier systems has enabled real-time monitoring and imaging of treatment response. This enables the assessment of therapy efficacy, the early diagnosis of recurrence, and the optimization of treatment regimens.