PDT Efficacy Research Articles

The Application of High-Frequency Ultrasonography in Post-Therapeutic Assessment of Actinic Keratosis After Photodynamic Therapy

Objectives: Actinic keratoses (AKs) are one of the most common reasons for consultation in the elderly population. This study aimed to assess the efficacy of 5-ALA PDT in AK treatment using high-frequency ultrasonography (HFUS) to evaluate skin layer changes during therapy. Methods: In our study, we included 44 AK patients aged 53 to 89 years. All patients had lesions clinically evaluated with the Olsen and AKASI scale. HFUS imaging was performed on seemingly healthy skin and lesions before and at 4, 8, and 12 weeks of therapy. Ultrasound markers such as skin thickness, echogenicity, and pixel intensity were measured. 5-ALA was applied under occlusion for 3 h. After removing the occlusive dressing, 5-ALA was removed with a saline solution and a directed therapy with a BF-200 lamp. Full follow-ups of 56 markers of suitable quality were selected. Results: The thickness of SLEB significantly decreased in the following weeks compared to the pre-therapy results, reaching its lowest values after 12 weeks. The average pixel intensity significantly increased in each skin layer after therapy (p < 0.01). For SLEB, there were statistically significant differences in LEP, MEP and contrast. The AKASI score before and after treatment was determined for the 39 patients who underwent follow-up at week 12. The median AKASI score was 3.2 (1.2–8.6) before treatment and 0.6 (0–2.8) after. Conclusions: According to the literature data, this is the first study describing the ALA-PDT treatment efficacy in different AK severities evaluated in HFUS. HFUS provides a valuable non-invasive tool for monitoring the efficacy of PDT in AK treatment, showing significant improvements in skin texture and structure.

Cyclodextrin-activated porphyrin-DNA nanofibers with AS1411/Hemin toehold for enhanced and targeted photodynamic therapy

Targeted photodynamic therapy is considered superior to conventional photodynamic therapy due to the enhanced uptake of photosensitizers by tumor cells. However, porphyrin-based photodynamic therapy is still limited due to the low hydrophilicity, poor biocompatibility and susceptibility to quenching of photosensitizers. Herein, we report cyclodextrin-activated porphyrin-DNA nanofibers with AS1411/Hemin toeholds, which enable targeted cancer cells recognition and catalytic oxygenation for enhanced photodynamic therapy. The nanofibers are formed through the self-assembly of the host–guest complex of cyclodextrin and porphyrin-DNA amphiphiles, and can be further functionalized on the surface with AS1411/Hemin. AS1411/Hemin can specifically target nucleolin-overexpressing cancer cells and catalyze conversion of excessive H2O2 into O2 within tumor cells, thereby alleviating tumor hypoxia and further cascaded enhancing PDT efficacy. These results suggest that the programmable and multifunctional nanofiber provided an effective nanoplatform for enhanced and targeted photodynamic therapy.

An Intelligent Triple Assisted Gold Cluster‐Based Nanosystem for Enhanced Tumor Photodynamic Therapy

Comprehensive SummaryPhotodynamic therapy (PDT) has been attracted a surge of research interest. However, there are several obstacles to limit the efficacy of PDT, such as hypoxic tumor microenvironment (TME), overexpressed glutathione (GSH), inefficient reactive oxygen species (ROS) generation, and so on. Herein, a smart responsive nanosystem was constructed, which was composed of Au25 modified with triphenylphosphine (Au25‐TPP), catalase (CAT) and GSH‐responsive diselenide‐bridged mesoporous silica nanoparticles (Se‐MSN). When the nanosystem arrived at tumor site, Se‐MSN was degraded by the intracellular overexpressed GSH to release Au25‐TPP and CAT. The Au25‐TPP was targeted to mitochondria and generated ROS under the 808 nm NIR laser irradiation to kill tumor cells. Simultaneously, CAT could catalyze hydrogen peroxide to provide oxygen for relieving the hypoxia of TME. Besides, GSH was consumed by the diselenide bond to diminish the ROS loss. The above tactics (mitochondria targeting, hypoxia relieving and GSH consuming) jointly enhanced the PDT efficacy. The nanosystem showed distinct in vitro anticancer effect significantly stronger than other groups containing one or two assistance. Moreover, the in vivo results suggested that the tumors could be restrained obviously. The current study provides a new inspiration for constructing novel inorganic nanomedicines with multiple enhancement effect of PDT efficacy.

Conventional versus daylight photodynamic therapy for recalcitrant hand warts: Efficacy, safety and recurrence

BackgroundAcral warts appear as skin-colored, verrucous, hyperkeratotic papules most located on the dorsal hands, distal fingers, subungual skin, and feet. Conventional photodynamic therapy (C-PDT) has shown a good efficacy and safety profile in patients with viral warts, in both adults and children, with a good cure rate and excellent cosmetic results in front of few and light side effects. The efficacy of daylight photodynamic therapy (DL-PDT) has not yet been evaluated. Objectivesto investigate and assess the short- and long-term efficacy of PDT using 10 % aminolevulinic acid (ALA) in the treatment of multiple verrucae vulgaris of the hands. The second endpoint was to compare the efficacy and safety of C-PDT versus DL-PDT. Materials and methods68 patients (38 males and 30 females) aged between 6 and 80 years, affected by hand warts, were divided into two arms: group A was treated with C-PDT, and group B was treated with DL-PDT. Patients underwent treatments three times at 1-month intervals. The response was assessed 3 months after the last session (W24) and 1 year after the last session (W52) and scored as excellent (75–100 % reduction of total wart count), partial (74−25 % reduction), and none (< 25 % reduction or no response). Any adverse events occurring during or after ALA application or irradiation as well as pain intensity were recorded at each visit. Results48 patients (70.6 %) achieved excellent response at W24, while 6 patients (8.8 %) had a partial response and 14 (20.6 %) were resistant to treatment. Patients treated with DL-PDT were less likely to have an excellent response (66.7 %) than patients treated with C-PDT (73.7 %), although not statistically significant. Among patients with excellent or partial response (n=54), 37 % (n=20) had warts relapse at W52. Both treatment modalities were well tolerated, with transient pain as the main side effects. ConclusionPDT is effective in the treatment of verrucae vulgaris of the hands. An overall response rate of 70.6 % of excellent response was achieved. While C-PDT showed a trend towards better outcomes, DL-PDT offered a more patient-friendly approach, particularly in terms of comfort and compliance.

Fluorescence imaging‐guided lipid droplets‐localized photodynamic therapy

AbstractPhotodynamic therapy (PDT) has emerged as a promising strategy for cancer treatment due to its non‐invasive nature and high specificity toward malignant tissues. In recent years, a variety of protocols have been proposed to improve the PDT efficacy, of which organelle‐targeted PDT strategy is supposed to be quite promising. Particularly, lipid droplets (LDs)‐localized PDT attracts a lot of interest due to the inherent advantages such as abundant LDs in cancer cells and their close relation with ferroptosis. This review provides a comprehensive summary of the advancements of LDs‐localized photosensitizers (PSs) according to their chemical structures and functions. Especially, these PSs are featured with fluorescence emission, thereby facilitating an imaging‐guided phototherapy. The review highlights the cytocidal actions of these PSs, such as the cell death pathway and their cytotoxicity. Finally, some unresolved issues and challenges in this domain will be discussed.

Cytocidal Effects of Interstitial Photodynamic Therapy Using Talaporfin Sodium and a Semiconductor Laser in a Rat Intracerebral Glioma Model.

This preclinical study was conducted to investigate the efficacy of interstitial PDT (i-PDT) for malignant gliomas arising deep within the brain, which are difficult to remove. C6 glioma cells were implanted into the basal ganglia of rats, and 3 weeks later, the second-generation photosensitizer talaporfin sodium (TPS) was administered intraperitoneally. Ninety minutes after administration, a prototype fine plastic optical fiber was punctured into the tumor tissue, and semiconductor laser light was irradiated into the tumor from a 2-mm cylindrical light-emitting source under various conditions. The brain was removed 24 h after the i-PDT and analyzed pathologically. The optical fiber was able to puncture the tumor center in all cases, enabling i-PDT to be performed. Histological analysis showed that tumor necrosis was induced in areas close to the light source, correlating with the irradiation energy dose, whereas apoptosis was induced at some distance from the light source. Irradiation using high energy levels resulted in tissue swelling from strong tumor necrosis, and irradiation at 75 J/cm2 was most suitable for inducing apoptosis. An experimental system of i-PDT using TPS was established using malignant glioma cells transplanted into the rat brain. Tumor cell death, which correlated with the light propagation, was induced in tumor tissue.

Determination of singlet oxygen quantum yield based on the behavior of solvent dimethyl sulfoxide oxidation by singlet oxygen

BackgroundPhotodynamic therapy (PDT) is emerging as a promising cancer treatment. The PDT efficacy is primarily attributed to the generation of singlet oxygen (1O2), stemming from the integrated effects of the photosensitizer, oxygen, and light. The singlet oxygen quantum yield (ΦΔ) serves as a bridge that links these parameters to the overall efficacy of PDT. The near-infrared luminescence of 1O2 provides a direct way for determining ΦΔ, but suffers from a poor signal-to-noise ratio. While the chemical trap probe method is detection-friendly, but it has a strict requirement for the excitation wavelength. Therefore, the existing methods for ΦΔ measurement are insufficient. ResultsIn this work, we developed an approach to determine ΦΔ of a broader range of photosensitizers using only the commonly used solvent dimethyl sulfoxide (DMSO), which can be oxidized by 1O2 to dimethyl sulfone. This method establishes the relationship between 1O2 production and changes in DMSO absorption spectra, eliminating the need for additional chemical probes. This method was validated by measuring the ΦΔ of rose bengal (RB) through systematic changes in absorption spectrum of DMSO under various RB concentrations and different excitation light power densities. Moreover, the ΦΔ of hematoporphyrin monomethyl ether (HMME), as determined by this method, is consistent with measurements obtained using the 1,3-diphenylisobenzofuran (DPBF) trapping probe. This consistency further validates the reliability of this method. Significance and noveltyThis work presents a direct, probe-free method to determine ΦΔ, reducing potential interference and expanding the range of useable excitation wavelengths. Its ability to measure ΦΔ using only DMSO enhances the accuracy of photosensitizer measurement, and broadens the applicability of the method to a wide range of samples, thereby advancing research on the properties of photosensitizers and further promoting the development of PDT.

Effect of photodynamic therapy on peripheral immune system for unresectable cholangiocarcinoma

BackgroundPhotodynamic therapy (PDT) has been emerging as a promising treatment for unresectable cholangiocarcinoma (CCA). A number of experiments have demonstrated that PDT could enhance antitumor immunity significantly. However, the impact of PDT on peripheral immune system for unresectable CCA remains unclear. MethodsIn a clinical trial comparing the perioperative and long-term outcomes of PDT+stent treatment and stent alone treatment for unresectable CCA, we tested the levels of lymphocytes (CD4+ T cells, CD8+ T cells, NK cells, B cells and Treg cells) and immune-related cytokines (IL-4, IL-6, IL-10, TNF-α, TGF-β, perforin, GM-CSF and IFN-γ) in peripheral blood before and after PDT+stent treatment or stent alone treatment and analyzed the influence of PDT on peripheral immune system for unresectable CCA. ResultsBefore treatment, the levels of all the immune cells and immune-related cytokines did not show significant differences between the PDT+stent group and stent alone group. The ratio of CD8+ T cells increased significantly after PDT treatment, but other kinds of lymphocytes did not show significant difference. Increased level of IL-6 and decreased level of perforin and TGF-β after PDT treatment were demonstrated, whereas no significant changes were found for other immune-related cytokines. ConclusionPDT altered the levels of immune cells and immune-related cytokines in the peripheral blood of unresectable CCA patients, potentially correlating with the therapeutic efficacy of PDT in unresectable CCA treatment. Future studies could delve deeper into this aspect to explore how PDT can be more effectively utilized in the management of unresectable CCA.

Relief of Biofilm Hypoxia: A Synergistic Approach with Cyanobacteria and Chlorin e6-Loaded Nanoparticles

AbstractPhotodynamic therapy (PDT) involves the use of photosensitizers, oxygen, and light to generate reactive oxygen species (ROS) for the effective destruction of cancer cells or bacteria. However, in biofilm bacterial infections, the presence of hypoxia significantly reduces the efficacy of PDT. To address this issue, we have developed a synergistic approach wherein Synechococcus elongatus (PCC 7942), cyanobacteria are loaded into a sodium alginate hydrogel, and chlorin e6 (Ce6) is conjugated with mesoporous silica nanoparticles (Ce6-MSNs). Cyanobacteria are photosynthetic organisms capable of releasing oxygen when exposed to 660 nm light. This property facilitates the effective production of ROS by Ce6-MSNs, even in hypoxic conditions, potentially enabling more effective PDT against MRSA planktonic bacteria and biofilm. Our results demonstrate that this system can maintain oxygen generation capacity for the test period of 30 days, thereby enhancing ROS production under hypoxic conditions. In summary, this innovative system combines cyanobacteria's photosynthetic oxygen generation with Ce6-MSNs' ROS production capabilities to address the challenge of hypoxia in biofilm infections. The promising results suggest its potential for improving the efficacy of PDT against bacterial infections, including drug-resistant strains such as MRSA. Graphical Abstract

Clinical trial of two-step photodynamic therapy for reduced pain in the treatment of precancerous squamous lesions (Actinic keratoses)

BackgroundPain associated with aminolevulinic acid photodynamic therapy (ALA-PDT) for the treatment of facial dermatoses results in low patient compliance. Two-step photodynamic therapy (two-step PDT) may improve comfort by optimizing light amplitude and exposure time. ObjectiveTo investigate the efficacy of two-step PDT in reducing the pain generated during the treatment of facial skin disorders. MethodsTwenty-six patients with AK were randomly divided into two groups; the experimental group was treated with two-step photodynamic therapy and the control group was treated with conventional photodynamic therapy. The pain intensity of the patients at different times was assessed using the pain numerical rating scale (NRS). ResultsA total of 26 patients completed three ALA-PDT treatments, 13 and 13 patients in each group, respectively. The mean NRS scores of patients in the experimental group (3.28±1.41, 3.33±1.43, 3.42±1.78) were lower than those of the control group (5.00±1.94, 5.09±1.86, 4.86±1.64) on each occasion. The incidence of certain adverse reactions was lower in the experimental group than in the control group. There was no difference between the two groups in terms of clinical outcome, recurrence rate and patient satisfaction. ConclusionTwo-step photodynamic therapy can reduce pain and the incidence of some adverse reactions, but does not affect clinical efficacy, recurrence rate and patient satisfaction.

Purine‐Based Ir(III) Photosensitizers for Efficient Treatment of Periodontal Inflammation

AbstractPhotodynamic therapy (PDT) presents a promising approach for combating periodontitis, an infectious disease triggered by bacteria. However, the hypoxic environment within periodontal pockets poses challenges for PDT efficacy. In this study, novel purine‐based C^N ligands are utilized to develop Ir(III) complexes with enhanced reactive oxygen species (ROS) generation capacity for periodontitis treatment. The type I/II PDT performance of Ir(III) is greatly enhanced by the purine ligands, which leads to potent bactericidal and biofilm elimination efficacy. In a rat model of periodontitis, local application of these purine‐based Ir(III) complexes effectively achieves antibacterial and anti‐inflammatory effects while promoting tissue repair under clinical luminaire exposure. This PDT strategy utilizing purine‐based Ir(III) complexes circumvents the need for antibiotics and surgical intervention, emerging as a promising, non‐invasive approach for managing periodontitis.

Nanoarchitectonics of fluorescent gold nanoclusters: A platform for image guided photodynamic therapy of hypoxic tumor

Metal nanoclusters are atomically precise materials comprising metal core of few atoms exhibiting unique photoluminescence properties, unlike their bigger counterparts. Some metal nanocluster with ligand-to-metal charge transfer, long-lived excited state and excited triplet state contribute to inherent photosensitizing (PS) property. However, the therapeutic efficacy of PDT is hindered by the insufficient oxygen supply (O2) in tumor microenvironment. In the present work, cysteine-capped gold nanocluster (AuC) are studied for their unique molecular architecture for PS efficiency. The co-existence of monodispersed and self-assembled structures contribute to the photoluminescence from the quantum confinement of electronic states and aggregation-induced emission (AIE) based PS property, respectively. In-silico model was performed to study the interaction of cysteine to gold cluster, its ground and excited-state properties and the charge transfer mechanism. The AuC as PS generates cytotoxic radicals in both Type I and Type II photodynamic pathways and the dominant radical species involved were elucidated by EPR spectroscopy. In vitro analysis in HeLa cells showed excellent biocompatibility and bioimaging properties. The intracellular ROS production and Live/Dead assay confirmed the generation of ROS in HeLa cells upon laser irradiation. The image-guided photodynamic property with synergistic Type I and Type II PDT reactions of AuC promises its potential application in cancer therapy in both hypoxic and normoxic conditions

Dual pH- and ATP-Responsive Antibacterial Nanospray: On-Demand Release of Antibacterial Factors, Imaging Monitoring, and Accelerated Healing of Bacteria-Infected Wounds under NIR Activation.

The prevalence of pathogenic bacterial infections with high morbidity and mortality poses a widespread challenge to the healthcare system. Therefore, it is imperative to develop nanoformulations capable of adaptively releasing antimicrobial factors and demonstrating multimodal synergistic antimicrobial activity. Herein, an NIR-activated multifunctional synergistic antimicrobial nanospray MXene/ZIF-90@ICG was prepared by incorporating ZIF-90@ICG nanoparticles onto MXene-NH2 nanosheets. MXene/ZIF-90@ICG can on-demand release the antimicrobial factors MXenes, ICG, and Zn2+ in response to variations in pH and ATP levels within the bacterial infection microenvironment. Under NIR radiation, the combination of MXenes, Zn2+, and ICG generated a significant amount of ROS and elevated heat, thereby enhancing the antimicrobial efficacy of PDT and PTT. Meanwhile, NIR excitation could accelerate the further release of ICG and Zn2+, realizing the multimodal synergistic antibacterial effect of PDT/PTT/Zn2+. Notably, introducing MXenes improved the dispersion of the synthesized antimicrobial nanoparticles in aqueous solution, rendering MXene/ZIF-90@ICG a candidate for application as a nanospray. Importantly, MXene/ZIF-90@ICG demonstrated antimicrobial activity and accelerated wound healing in the constructed in vivo subcutaneous Staphylococcus aureus infection model with NIR activation, maintaining a favorable biosafety level. Therefore, MXene/ZIF-90@ICG holds promise as an innovative nanospray for adaptive multimodal synergistic and efficient antibacterial applications with NIR activation.

Analysis of non-linear optical properties of phytochemical photosensitizers in cancer photodynamic therapy by quantum computational

RationalePhotodynamic therapy (PDT) is based on the reactive oxygen species (ROS) generated by light-activated photosensitizers in the presence of oxygen. Phytochemicals are promising natural photosensitizers, offering a potentially less toxic alternative for cancer treatments. Nonlinear optics (NLO) phenomena, such as second-harmonic generation (SHG), third-harmonic generation (THG), and two-photon absorption (TPA), can enhance light interaction, benefiting photosensitizing applications in PDT. Analyzing the NLO properties of phytochemicals can optimize their use in PDT by improving photosensitizer performance and efficacy. AimThis study aims to examine the NLO properties of selected phytochemicals in a reported polyherbal formulation to understand their potential as effective photosensitizers in PDT, thereby advancing cancer treatment options. MethodsQuantum computational calculations were conducted at the B3LYP/6311 G++(d,p) level of theory to unveil crucial information about structural geometry and nonlinear optical properties. ResultsThe bandgap of aloe emodin, emodin, curcumin, scopoletin berberine, furanocoumarin, rubiadin are 3.279 eV, 3.395 eV, 3.247 eV, 3.930 eV, 2.878 eV, 4.463 eV and 3.546 eV, respectively. The results highlight berberine as the most reactive compound, demonstrating high softness and low hardness. Curcumin and furanocoumarin exhibit distinct electron-donating and accepting tendencies, respectively. In the MESP map of furanocoumarin, scopoletin, and rubiadin the electro-negative region is highly oriented around the ketone group (=O) and partially at another O atom in the pentagon. The compensating electropositive charge was distributed elsewhere. In aloe emodin, emodin, and curcumin the electronegativity was distributed around the ketone group while high electropositivity was observed around the substituted hydroxyl functional groups. In berberine electro negative region is very small and it is more electro-positive in nature. All the selected compounds have significantly greater dipole moment than standard urea (1.3732 Debye), specifically scopoletin and curcumin has 8 times greater value than urea. Concerning chemical potential, curcumin emerges as easily reactive, than berberine. The evaluation of NLO properties, including dipole moment (µ), polarizability (α), and mean first hyperpolarizability (β), underscores the superiority of berberine, making it highly reactive and easily activated during laser light irradiation. Discussion and conclusionBerberine exhibits superior NLO properties, marked by high reactivity, substantial softness, and significant first hyperpolarizability, making it the most effective photosensitizer among the studied phytochemicals for enhancing PDT efficacy in cancer treatments.

Comparison of the Differences between Two-Photon Excitation, Upconversion, and Conventional Photodynamic Therapy on Cancers in In Vitro and In Vivo Studies.

Nine electronic databases were searched, including WanFang Data, PubMed, Science Direct, Scopus, Web of Science, Springer Link, SciFinder, and China National Knowledge Infrastructure (CNKI), without any language constraints. TPE and UCNP were evaluated to determine if they had different effects from PDT on cancers. All eligible studies were analyzed and summarized in this review. TPE-PDT and UCNP-PDT have a high cell or tissue penetration ability through the excitation of NIR light to activate PS molecules. This is much better than the conventional PDT induced by visible or ultraviolet (UV) light. These studies showed a greater PDT efficacy, which was determined by enhanced generation of reactive oxygen species (ROS) and reduced cell viability, as well as inhibited abnormal cell growth for the treatment of cancers. Conventional PDT involves Type I and Type II reactions for the generation of ROS in the treatment of cancer cells, but there are some limitations. Recently, TPE-PDT and UCNP-PDT have been developed to overcome these problems with the help of nanotechnology in in vitro and in vivo studies.

Ternary heterostructure-driven photoinduced electron-hole separation enhanced oxidative stress for triple-negative breast cancer therapy

Zinc oxide nanoparticles (ZnO NPs) stand as among the most significant metal oxide nanoparticles in trigger the formation of reactive oxygen species (ROS) and induce apoptosis. Nevertheless, the utilization of ZnO NPs has been limited by the shallowness of short-wavelength light and the constrained production of ROS. To overcome these limitations, a strategy involves achieving a red shift towards the near-infrared (NIR) light spectrum, promoting the separation and restraining the recombination of electron-hole (e−-h+) pairs. Herein, the hybrid plasmonic system Au@ZnO (AZ) with graphene quantum dots (GQDs) doping (AZG) nano heterostructures is rationally designed for optimal NIR-driven cancer treatment. Significantly, a multifold increase in ROS generation can be achieved through the following creative initiatives: (i) plasmonic Au nanorods expands the photocatalytic capabilities of AZG into the NIR domain, offering a foundation for NIR-induced ROS generation for clinical utilization; (ii) elaborate design of mesoporous core-shell AZ structures facilitates the redistribution of electron-hole pairs; (iii) the incorporation GQDs in mesoporous structure could efficiently restrain the recombination of the e−-h+ pairs; (iv) Modification of hyaluronic acid (HA) can enhance CD44 receptor mediated targeted triple-negative breast cancer (TNBC). In addition, the introduced Au NRs present as catalysts for enhancing photothermal therapy (PTT), effectively inducing apoptosis in tumor cells. The resulting HA-modified AZG (AZGH) exhibits efficient hot electron injection and e−-h+ separation, affording unparalleled convenience for ROS production and enabling NIR-induced PDT for the cancer treanment. As a result, our well-designed mesoporous core-shell AZGH hybrid as photosensitizers can exhibit excellent PDT efficacy.

Enhanced phototoxicity and specificity of AlPCS4 when loaded in liposomes conjugated with a MET-targeting nanobody

SignificancePhotodynamic therapy (PDT) improves the survival of cholangiocarcinoma patients. Here, to improve the pharmacokinetics and efficacy of PDT, AlPCS4 was encapsulated into liposomes conjugated with a nanobody. ApproachAlPCS4 was loaded in liposomes conjugated with a nanobody targeting hepatocyte growth factor receptor (MET). The uptake of the MET-targeted liposomes (MET-TLs) and non-targeted liposomes (NTLs) was studied with confocal microscopy and flow-cytometry. Phototoxicity of MET-TLs and NTLs was tested by exposing MET-positive (TOV+MET, EGI1) and MET-negative (TOV112D) cells to a range of AlPCS4 concentrations. After incubation, cells were illuminated and cell viability was measured with MTS assay. ResultsMET-TLs were more internalized by MET-positive cells and induced higher phototoxicity than NTLs (LC50 was 10 × lower for MET-TLs). No phototoxicity was observed on MET-negative cells and in non-illuminated controls for the concentrations tested. ConclusionsThis study demonstrated that MET-TLs can increase the specificity of AlPCS4 towards cancer cells and enhance phototoxicity.

Optimization of Nasopharyngeal carcinoma (NPC) spheroid formation for 5-ALA PDT study

SignificanceRecently, there is an increase in PDT studies using 3D spheroids. However, there is limited information demonstrating the effect of spheroid size on PDT study. This study aims to provide information on the effect of NPC/CNE2 spheroid size on PpIX accumulation and PDT efficacy. ApproachNPC/CNE2 spheroids were generated with different initial cell densities (5,000-60,000 cells/well). Spheroids’ diameter and morphological characteristics were recorded for 5 days and post-PDT 24-72 hours. The intracellular PpIX accumulation was measured by the Incucyte S3 live-cell analysis system. ResultsSpheroid size increased with initial cell density increased. Spheroids formed within 5,000-20,000 cells were less varied in size and with smooth round edges. The PpIX accumulation was spheroid size-dependent with PpIX accumulation increased in larger spheroids. 5-ALA-PDT inhibited spheroid growth with a decrease in size of periphery compared to the control. ConclusionsThe spheroid size is an important factor affects in vitro PDT study.

In vitro Proof of Concept of Photodynamic Therapy Efficiency in the Treatment of Glioblastoma

Significance5-ALA photodynamic therapy (5-ALA-PDT) could be a novel approach to treat glioblastoma. However, we observed an in vitro resistance of human glioblastoma cells to 5-ALA-PDT. ABCG2, a transporter responsible of the efflux of the photosensitizer protoporphyrine IX (PpIX) could be implied in this resistance. We aimed here to correlate PpIX accumulation and ABCG2 transporter expression with the efficacy of in vitro PDT on glioblastoma. ApproachFor each of 6 cell lines (4 glioblastomas, 2 controls), assessment of: cell death after PDT (Cell viability); PpIX metabolization and efflux (fluorometry); ABCG2 transporter transcriptomic expression (RTqPCR) and proteinic expression (Western-blot; flow cytometry); PpIX and ABCG2 transporter localization (Confocal microscopy). ResultsWe have observed different time and dose dependent PDT efficacy and PpIX metabolization regarding the different cell lines studied. ConclusionsThere is a correlation between intracellular PpIX, its efflux, and PDT efficacy. Our preliminary results need to be correlated with ABCG2 expression.

Cucumber‐Derived Extracellular Vesicle‐Functionalized Metal‐Organic Frameworks for Enhanced Photodynamic Therapy of Hypertrophic Scars

AbstractPhotodynamic therapy (PDT) with noninvasiveness and high safety has emerged as a promising therapeutic approach for the management of hypertrophic scars (HS). However, the low transdermal delivery and overexpressed levels of intracellular glutathione (GSH) severely hinder its therapeutic effectiveness. Herein, a multifunctional biomimetic nanoplatform (NDs@EV‐RGD) composed of arginine‐glycine‐aspartic acid (RGD)‐modified cucumber‐derived extracellular vesicles (EVs) and copper‐based metal‐organic framework nanodots (Cu‐MOF NDs) is designed for PDT‐mediated HS treatment. The EVs with low Young's modulus exhibit excellent deformability which endow NDs@EV‐RGD with the capacity to overcome the compact stratum corneum barrier, thereby significantly improving their transdermal delivery efficiency. Notably, the RGD targeting peptide displays specific binding to α1β1 integrin on the fibroblast membranes within HS, leading to the high accumulation efficiency of NDs@EV‐RGD at the HS site. Under near‐infrared laser irradiation, NDs@EV‐RGD efficiently generates abundant reactive oxygen species, inducing the apoptosis of excessively proliferated fibroblasts. Moreover, Cu‐MOF NDs interact with the local GSH, leading to GSH depletion and a significant enhancement in PDT efficacy. Furthermore, NDs@EV‐RGD demonstrates a remarkable therapeutic effect in improving the appearance of HS in a rabbit ear HS model, promoting the apoptosis and remodeling of collagen fibers. Therefore, this work provides a promising biomimetic platform for HS treatment.