Combination Of Photosensitizer Research Articles

EFFECT OF LOW LEVEL LASER OF 650NM ON VIALBILITY OF PREVOTELLA INTERMEDIAWITH AND WITHOUT PHOTOSENSITISERS: AN IN VITRO STUDY

Background: Prevotella intermedia is commonly associated with various forms of periodontal disease. Conventional treatment involves a combination of mechanical therapy and systemic antibiotics administration, which comes with its own set of challenges and disadvantages. An alternative treatment modality is low-level laser therapy with and without photosensitizers. Purpose: This study aimed to evaluate the effectiveness of low-level laser therapy with and without the use of photosensitizers, specifically Methylene blue and Toluidine blue, on the viability of Prevotella intermedia. Methods: The study utilized in vitro experiments to assess the impact of low-level laser therapy alone and in combination with photosensitizers on the viability of Prevotella intermedia. Results: The findings indicate that Methylene blue, when combined with low-level laser therapy, exhibits bactericidal effects similar to or greater than low-level laser therapy alone on Prevotella intermedia. Additionally, the use of Toluidine blue as a photosensitizer in combination with low-level laser therapy also led to a reduction in the viability of Prevotella intermedia, although it was not as effective as Methylene blue. Conclusion: Low-level laser therapy, particularly when combined with Methylene blue as a photosensitizer, shows promise as a potential treatment modality for controlling Prevotella intermedia in periodontal diseases.

Photosensitizers combination approach to enhance photodynamic inactivation of planktonic and biofilm bacteria.

To improve bacterial photodynamic inactivation (PDI), this work analyzes the photodynamic effect caused by the combination of photosensitizers (PSs) on two bacterial models and different growth mode. Simultaneous administration of PSs from different families, zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine (ZnPPc4+), 5,10,15,20-tetra(4-N,N,N-trimethylammonium phenyl)porphyrin (TMAP4+), meso-tetrakis(9-ethyl-9-methyl-3-carbazoyl)chlorin (TEMCC4+) and 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl] chlorin (TAPC) was investigated against Staphylococcus aureus and Escherichia coli, in planktonic form, biofilm and growth curve. Various PSs combinations showed greater inactivation compared to when used separately under the same conditions but at twice the concentration. However, differences were found in the effectiveness of the PSs combinations on Gram positive and negative bacteria, as well as in planktonic or biofilm form. Likewise, the combination of three PSs completely stopped E. coli growth under optimal nutritional conditions. PSs combination allows extending the range of light absorption by agents that absorb in different areas of the visible spectrum. Therefore, PDI with combined PSs increases its antimicrobial capacity using agents' concentrations and light fluences lower than those necessary to cause the same effect as single PS. These advances represent a starting point for future research on the potentiation of PDI promoted by the combined use of PSs.

Recent Advances of Transition Metal Complexes for Photopolymerization and 3D Printing under Visible Light

AbstractThe possibility of exploiting visible light to induce polymerizations is extremely appealing from a technological point of view as it improves the sustainability of the overall process. To achieve this objective, it is necessary to employ single‐ or multicomponent systems containing a photoinitiator, and in some cases, a photosensitizer in combination. Due to their long‐lived excited states and reversible redox properties, transition metal complexes are a valid choice to be applied in photoinitiating systems, often exhibiting enhanced conversions compared to purely organic compounds. This review presents an overview of the transition metal complexes exploited in photopolymerization reactions. Particular attention will be devoted to recent applications in 3D printing, highlighting the possible challenges that need to be faced to achieve highly efficient and more sustainable processes.

More-Is-Better Strategy for Constructing Homoligand Polypyridyl Ruthenium Complexes as Photosensitizers for Infrared Two-Photon Photodynamic Therapy

Photodynamic therapy (PDT) uses a combination of photosensitizers (PSs), light sources, and reactive oxygen species (ROS) to damage only the desired target and keep normal tissues from being hurt. The dark cytotoxicity (chemotoxicity) of PSs, leading to whole-body damage in the absence of irradiation, is a major limiting factor in PDT. How to simultaneously increase ROS generation and decrease dark cytotoxicity is an essential challenge that must be resolved in PS research. In this study, a series of homoligand polypyridyl ruthenium complexes (HPRCs) containing three singlet oxygen (1O2)-generating ligands (L) in a single molecule ([Ru(L)3]2+) have been constructed. Compared to the heteroligand complexes [Ru(bpy)2(L)]2+ where bpy is 2,2'-bipyridine, the 1O2 quantum yield under infrared two-photon irradiation and the DNA photocleavage effect of the HPRCs are significantly enhanced with two more ligands L. The intraligand triplet excited states transition played an important role in the activation of oxygen. The HPRCs target the mitochondria but not the nuclei, generating 1O2 intracellularly under irradiation of visible or infrared light. Ru1 exhibits high phototoxicity and low dark cytotoxicity toward human malignant melanoma cells in vitro. Moreover, HPRCs have minimal cytotoxicity to human normal liver cells, suggesting their potential as antitumor PDT reagents with more security. This study may provide inspiration for the structural design of potent PS for PDT.

Photocatalytic CO2 reduction with a TiO2-supported copper photosensitizer and an iron-based CO2 reduction catalyst

Selective photocatalytic carbon dioxide reduction to carbon monoxide is achieved employing a supported photosensitizer in combination with an iron catalyst. The composite material showed a better performance than the purely homogeneous system.

Combination of photosensitizer and immune checkpoint inhibitors for improving the efficacy of tumor immunotherapy

As a new type of antitumor strategy, the combined application of photodynamic therapy and immunotherapy will be a breakthrough in the field of tumor therapy. In this study, PD-L1McAb&HMME@Clip is used as the carrier to improve the low tumor response rate of immune checkpoint inhibitors. Firstly, by passive targeting technology, the carrier is delivered to the tumor site to increase the local drug concentration. Then, by photodynamic technology, HMME can produce large amount of reactive oxygen species and directly kill the tumor cells. Meanwhile, the tumor cell lysate with strong immunogenicity can promote the phagocytosis of dendritic cells and the activation of initial T cells. Finally, by immune technology, the PD-1/PD-L1 pathway is blocked in the tumor microenvironment, the killing ability of T cells to tumor cells can be restored, and the tumor recurrence and metastasis can be effectively inhibited by the autoimmune system, so as to achieve the goal of tumor treatment. Furthermore, we also highlight the potential benefits of immunotherapy as a surgical adjuvant therapy.

Evaluating Therapeutic Effects of In Vivo 15MV Radiodynamic Therapy (RDT) with 5-Aminolevulinic Acid (5-ALA) Using 1.5T MRI and [18F]FDG PET/CT

<h3>Purpose/Objective(s)</h3> A combination of photosensitizer and high-energy photon beam is required to perform radiodynamic therapy (RDT) for tumor treatment. High-energy photon beams activate the photosensitizer, leading to cellular toxicity by producing extra reactive oxygen species to kill malignant cells. The purpose of this study was to investigate the therapeutic effect of RDT with 15 MV photon beams combined with 5-aminolevulinic acid (5-ALA) using a mouse model. <h3>Materials/Methods</h3> All animal studies were approved by our Institutional Animal Care and Use Committee. A subcutaneous murine KP1 small-cell lung cancer model using C57BL/6 mice was used. The tumors (n=126) were randomly assigned into four groups, including control (untreated), radiation treatment (RT) only, 5-ALA only, and RDT to observe individual and synergistic effects of 5-ALA and radiation treatment. Treatment was performed when the tumor reached 5-8 mm in diameter. A single fraction of 4 Gy was delivered to the tumors using 15 MV photons on a clinical linear accelerator for RT only and RDT groups. 5-ALA was injected at 100 mg/kg by tail-vein 4 hours prior to RT for 5-ALA only and RDT groups. Tumor volumes were measured using a 1.5 T MR scanner on the day of treatment and weekly post-treatment. Tumor growth for each tumor was quantified as the ratio of tumor volume one- and two-week post-treatment to the tumor volume on the treatment day. SUV_max and total lesion glycolysis (TLG) were measured using [¹⁸F]FDG PET/CT for control and RDT groups. A 10 min static scan was acquired an hour after an injection of 80 µCi [¹⁸F]FDG. SUV_max was calculated as the maximum measured activity concentration divided by the injected whole bodyweight activity concentration. TLG was quantified as a product of SUV_mean and the metabolic tumor volume. <h3>Results</h3> The tumor growth in the RDT group was delayed by 48.3±11.3%, 46.3±9.2%, and 54.6±12.7% at one-week post-treatment compared to 5-ALA only, RT only, and the control group (P<0.001), respectively. There were no significant differences in tumor growth between 5-ALA only, RT only, and the control group. Moreover, about a 40% additional decrease in tumor growth was observed, showing a synergistic effect of RDT. SUV_max and TLG showed 47.4±8.8% and 66.5±5.3% decrease at one-week post-treatment, respectively. Also, a higher number of distant metastases were observed using [¹⁸F]FDG PET/CT in the control group than in the RDT group. <h3>Conclusion</h3> Assessment of radiodynamic therapy combined with 5-ALA administration and 15 MV high-energy radiation treatment showed improved treatment outcomes compared to the control, RT only, and 5-ALA only groups. Tumor growth delay and tumor activity suppression were significantly improved. Moreover, a synergistic effect of 5-ALA and 15 MV photon beams was observed. The preliminary (hypothesis-generating) results advocate a further investigation into larger sample sizes.

Photodynamic Inactivation Property of Saffron (Crocus sativus) as a Natural Photosensitizer in Combination with Blue Light in Microbial Strains

Photodynamic Inactivation Property of Saffron (Crocus sativus) as a Natural Photosensitizer in Combination with Blue Light in Microbial Strains

Second harmonic generation nanoparticles enables Near-Infrared Photodynamic Therapy from visible light reactive photosensitizer conjugates.

Combination of photosensitizers (PS) with nanotechnology can improve the therapeutic efficiency of clinical Photodynamic Therapy (PDT) by converting visible light reactive PSs into Near-Infrared (NIR) light responsive molecules using Harmonic Nanoparticles (HNP). To test the PDT efficiency of HNP-PS conjugates, pathogenic S. aureus cell cultures were treated with perovskite (Barium Titanate) Second Harmonic Generation (SHG) nanoparticles conjugated to photosensitizers (PS) (we compared both FDA approved Protoporphyrin IX and Curcumin) and subjected to a femtosecond pulsed Near-Infrared (NIR) laser (800 nm, 232–228 mW, 12–15 fs pulse width at repetition rate of 76.9 MHz) for 10 minutes each. NIR PDT using Barium Titanate (BT) conjugated with Protoporphyrin IX as HNP-PS conjugate reduced the viability of S. aureus cells by 77.3 ± 9.7% while BT conjugated with Curcumin did not elicit any significant effect. Conventional PSs reactive only to visible spectrum light coupled with SHG nanoparticles enables the use of higher tissue penetrating NIR light to generate an efficient photodynamic effect, thereby overcoming low light penetration and tissue specificity of conventional visible light PDT treatments.

Back Cover: Partial Metalation of Porphyrin Moieties in Hydrogen‐Bonded Organic Frameworks Provides Enhanced CO2 Photoreduction Activity (Angew. Chem. Int. Ed. 28/2022)

A biomimetic catalyst for CO2 photoreduction was developed through self-assembling porphyrins into a hydrogen-bonded organic framework, as reported by Tian-Fu Liu, Rong Cao, and co-workers in their Research Article (e202203955). The combination of photosensitizers and redox centers in the structure not only allows for adequate photon input and efficient utilization of the photogenerated charge, but also changes the microenvironment surrounding the active sites.

Photocatalytic Multielectron Reduction of Nitroarenes to Anilines by Utilizing an Electron-Storable Polyoxometalate-Based Metal-Organic Framework.

A powerful approach to generate photocatalysts for the highly selective reduction of nitrobenzene using light as the driving force is a combination of photosensitizers and electron-storable components in a cooperative photocatalysis fashion. Herein, a new precious metal-free photocatalyst, {ZnW-TPT}, was prepared by incorporating a Zn-substituted monovacant Keggin polyanion [SiZnW11O39]6- and a photoactive organic bridging link 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT) into a framework. In this structure, the direct coordination bond between [SiZnW11O39]6- and the TPT ligand and the π-π interactions between TPT molecules help separate and migrate photogenerated carriers, which improves the photocatalytic activity of {ZnW-TPT}. The photoelectrochemical properties of {ZnW-TPT} were well studied by solid UV-vis absorption, fluorescence, transient photocurrent response, and electrochemical impedance spectroscopy tests. {ZnW-TPT} efficiently converts using hydrazine hydrate with 99% conversion and 99% selectivity for anilines under mild conditions.

Self-assembly of nanomicelles with rationally designed multifunctional building blocks for synergistic chemo-photodynamic therapy.

Rationale: The combination of photosensitizers, oxygen supply agents, and adjuvant therapy drugs in a single nano-drug delivery system for photodynamic therapy (PDT) has been showing great promises to overcome the inherent challenges of PDT for tumor treatment. However, the complicated preparation of integrating multiple components hampers their further developments. Here, we describe a self-assembly nanomicelle with rationally designed building blocks, which shows a high efficiency of synergistic chemo-photodynamic therapy in the animal modal.Methods: The nanomicelle was prepared by a coordination-driven self-assembly based on a rationally designed ferrocene cyclopalladated compound coupled with photosensitizers and hyaluronic acid (referred to as FCP-Tph/HA). The morphology, targeting drug delivery, pharmacokinetics, hemolysis, and multimodal synergistic therapy of FCP-Tph/HA were investigated.Results: The formation of nanomicelles presents a low hemolysis rate and a prolonged blood circulation time. FCP-Tph/HA possesses an enhanced antitumor effect in vitro through the specific binding of HA to CD44 and combining chemotherapy with oxygen self-supplying PDT. Simultaneously, the nanomicelle facilitates a significantly improved antitumor efficacy (>90% tumor regression) on a breast cancer model in vivo.Conclusion: Our results present a modular self-assembled nanomicellar platform with synergistic chemo-photodynamic therapy for challenging PDT-based tumor treatment.

Panoramic insights into semi-artificial photosynthesis: origin, development, and future perspective

This review comprehensively elaborates the modes of semi-artificial photosynthetic systems (SAPSs) based on the different combinations of photosensitizers and catalytic centers for energy and environmental application.

Pharmacokinetics and tissue distribution characteristics of the novel photosensitizer 32-(4-methoxyphenyl)-152-aspartyl-chlorin e6

二氢卟吩类衍生物32-(4-甲氧基苯基)-152-天冬氨酸-二氢卟吩e6(DYSP-C34)是从程海湖螺旋藻中提取并合成的新型光敏剂。研究DYSP-C34在生物体内的药代动力学及组织分布过程对光动力疗法(PDT)的有效性和安全性至关重要。该文运用高效液相色谱-紫外(HPLC-UV)检测技术,建立了大鼠血浆中DYSP-C34的检测方法。采用沉淀蛋白-液液萃取法处理血浆和组织样品,采用Unitary C18色谱柱(250 mm×4.6 mm, 5 μm)分离,流动相为甲醇-5 mmol/L四丁基磷酸氢铵缓冲盐溶液(70:30, v/v),流速为1.0 mL/min,进样量为20 μL,检测波长为400 nm,柱温为40 ℃。实验结果表明,大鼠血浆药物质量浓度在1~200 μg/mL范围内线性良好,判定系数(r2)为0.9941。在低、中、高(8、40、120 μg/mL)3个添加水平下的提取回收率分别为74.39%、69.71%和65.89%,日内和日间相对标准偏差(RSD)均在5%以内。运用此方法测定静脉注射DYSP-C34(16 mg/kg)后大鼠血浆中以及荷瘤小鼠组织中的药物浓度,采用DAS 2.0计算出药物半衰期t1/2z为6.98 h,药-时曲线下面积AUC(0-∞)为1025.01 h·mg/L,平均驻留时间MRT(0-∞)为9.19 h。DYSP-C34在荷瘤小鼠体内的分布结果显示,DYSP-C34可以在肿瘤组织中蓄积,并具有一定的滞留作用。综上,该文建立了大鼠血浆中DYSP-C34的HPLC-UV测定方法,并进行了方法学验证,此方法简便、快速,结果准确。阐明了DYSP-C34在静脉给药方式下大鼠体内药代动力学和荷瘤小鼠组织中的分布特征,对临床合理用药和药效学研究具有重要意义。

Cancer immunogenic cell death via photo-pyroptosis with light-sensitive Indoleamine 2,3-dioxygenase inhibitor conjugate

Immune checkpoint blockade (ICB) therapy currently considered as to be effective way to cure cancer in clinic. However, the insufficient tumor immunogenicity and the immunosuppressive tumor microenvironment always result in diminished efficacy of immunotherapy. Herein, we report the synthesis of an organic photo-immune activator NBS-1MT, the combination of photosensitizer and Indoleamine 2,3-dioxygenase (IDO) inhibitor effectively stimulates lysosomes oxidative stress the releases inflammatory cytokines. This process triggers pyroptosis for the considerable immunogenic cell death (ICD) while reversing suppressive tumor microenvironment. The photo-immune drug shows outstanding potential to activate caspase-1and then remove gasdermin-D (GSDMD), which could stimulate pyroptosis and also inhibit the tumor growth successfully in both primary and distant tumor. Furthermore, pyroptosis activated by photodynamic therapy (PDT) promotes the immune related factors release, and enhance the intratumoral infiltration of cytotoxic T lymphocytes (CTLs) with the induction of ICD of tumor cells and the cascaded synergize with IDO inhibitor, so the general antitumor immune response could be strengthened effectively. Our research confirms that the use of NBS-1MT is a promising strategy to boost the immune response and eventually to inhibit tumor growth.

Sensitized Photocatalytic CO2 Reduction With Earth Abundant 3d Metal Complexes Possessing Dipicolyl-Triazacyclononane Derivatives.

Complexes based on nitrogen and sulfur containing ligands involving 3d metal centers are known for the electrocatalytic reduction of CO2. However, photocatalytical activation has rarely been investigated. We herein present results on the light-driven CO2 reduction using either Ir(dFppy)3 [Ir, dFppy = 2-(4,6-difluorophenyl)pyridine] or [Cu(xant)(bcp)]+, (Cu, xant = xantphos, bcp = bathocuproine) as photosensitizer in combination with TEA (triethylamine) as sacrificial electron donor. The 3d metal catalysts have either dptacn (dipicolyl-triazacyclononane, L N3 ) or dpdatcn (dipicolyl-diazathiocyclononane, L N2S ) as ligand framework and Fe3+, Co3+ or Ni2+ as central metal ion. It turned out that the choice of ligand, metal center and solvent composition influences the selectivity for product formation, which means that the gaseous reduction products can be solely CO or H2 or a mixture of both. The ratio between these two products can be controlled by the right choice of reaction conditions. With using Cu as photosensitizer, we could introduce an intermolecular system that is based solely on 3d metal compounds being able to reduce CO2.

The application of antimicrobial photodynamic inactivation on methicillin-resistant S. aureus and ESBL-producing K. pneumoniae using porphyrin photosensitizer in combination with silver nanoparticles.

As resistance of bacterial strains to antibiotics is a major problem, there is a need to look for alternative treatments. One option is antimicrobial photodynamic inactivation (aPDI). The pathogenic cells are targeted by a nontoxic photosensitizer while the surrounding healthy tissue is relatively unaffected. The photosensitizer is activated by light of t appropriate wavelength resulting in the generation of reactive oxygen species that are cytotoxic for the pathogens. In this work, the photosensitizer TMPyP and silver nanoparticles (AgNPs) were investigated for their synergistic antibacterial effect. We tested these two substances on two bacterial strains, methicillin-resistant Staphylococcus aureus 4591 (MRSA) and extended-spectrum beta-lactamases-producing Klebsiella pneumoniae 2486 (ESBL-KP), to compare their effectiveness. The bacteria were first incubated with TMPyP for 45 min or 5 h, then irradiated with a LED source with the total fluence of 10 or 20 J/cm2 and then placed in a microbiological growth medium supplemented with AgNPs. To accomplish the synergistic effect, the optimal combination of TMPyP and AgNPs was estimated as 1.56-25 μM for TMPyP and 3.38 mg/l for AgNPs in case of MRSA and 1.56-50 μM for TMPyP and 3.38 mg/l for AgNPs in case of ESBL-KP at 45 min incubation with TMPyP and fluence of 10 J/cm2. Longer incubation and/or longer irradiation led to a decrease in the maximum values of the photosensitizer concentration to produce the synergistic effect. From this work it can be concluded that the combination of antimicrobial photodynamic inactivation with a treatment including silver nanoparticles could be a promising approach to treat bacterial infection.

Propolis nanoparticle enhances the potency of antimicrobial photodynamic therapy against Streptococcus mutans in a synergistic manner

Less invasive removal approaches have been recommended for deep caries lesions. Antimicrobial photodynamic therapy (aPDT) and propolis nanoparticle (PNP) are highlighted for the caries management plan. Evidence is lacking for an additive effect of combination PNP with photosensitizer (PS) in aPDT. This study aimed to investigate the individual and synergistic effects of chlorophyllin-phycocyanin mixture (PhotoActive+) and toluidine blue O (TBO) as PSs in combination with PNP in the aPDT process (aPDTplus) against major important virulence factors of Streptococcus mutans. Following characterization, biocompatibility of the PSs alone, or in combination with PNP were investigated on human gingival fibroblast cell. The in vitro synergy of PhotoActive+ or TBO and PNP was evaluated by the checkerboard method. The bacteria's virulence properties were surveyed in the presence of the PSs, individually as well as in combination. When the PSs were examined in combination (synergistic effect, FIC Index < 0.5), a stronger growth inhibitory activity was exhibited than the individual PSs. The biofilm formation, as well as genes involved in biofilm formation, showed greater suppression when the PSs were employed in combination. Overall, the results of this study suggest that the combination of PhotoActive+ or TBO with PNP with the least cytotoxicity effects and the highest antimicrobial activites would improve aPDT outcomes, leading to synergistic effects and impairing the virulence of S. mutans.

Novel inactivation of the causative fungal pathogenof white-nose syndrome with methoxsalen plusultraviolet A orB radiation.

White-nose syndrome is a fungal disease responsible for the rapid decline of North American bat populations. This study addressed a novel method for inactivating Pseudogymnoascus destructans, the causative agent of WNS, using ultraviolet A (UVA) or B (UVB) radiation in combination with methoxsalen, a photosensitizer from the furanocoumarin family of compounds. Fungal spore suspensions were diluted in micromolar concentrations of methoxsalen (50–500 μM), then exposed to fixed doses of UVA radiation (500–5000 mJ/cm2), followed by plating on germination media. These plates were examined for two to four weeks for evidence of spore germination or inactivation, along with resultant growth or inhibition of P. destructans colonies. Pretreatment of fungal spores with low doses of methoxsalen resulted in a UVA dose-dependent inactivation of the P. destructans spores. All doses of methoxsalen paired with 500 mJ/cm2 of UVA led to an approximate two-log10 (~99%) reduction in spore viability, and when paired with 1000 mJ/cm2, a four-log10 or greater (>99.99%) reduction in spore viability was observed. Additionally, actively growing P. destructans colonies treated directly with methoxsalen and either UVA or UVB radiation demonstrated UV dose-dependent inhibition and termination of colony growth. This novel approach of using a photosensitizer in combination with UV radiation to control fungal growth may have broad, practical application in the future.

Effect of Foslip® mediated photodynamic therapy on 5-fluorouracil resistant human colorectal cancer cells.

Colorectal cancer (CRC) is the commonest cancer in Hong Kong and is often treated with 5-fluorouracil (5-FU). However the clinical application of 5-FU was limited by drug resistance in CRC. Photodynamic therapy (PDT) is a novel treatment combating CRC via the combination of photosensitizer, molecular oxygen and light activation. In this study, 5-FU resistant HT29 (HT29FU) was established and its susceptibility to Foslip® PDT tested. Effect of 5-FU to HT29 cells was measured via qPCR. Efficacy of Foslip® PDT on HT29 and HT29FU cells were measured via photosensitizer uptake, cellular localization, cytotoxicity, cell cycle distribution and signal proteins expression. 5-FU significantly induced ABCB1 mRNA expression in HT29 cells; whereas with a 24 fold increase in HT29FU cells. Both cells responded similarly to Foslip® PDT, with the inhibitory concentration IC20, IC50 and IC70 achieved at 1 ng/mL, 2 ng/mL and 5 ng/mL with 2 J/cm2 light activation respectively. Foslip® PDT triggered apoptosis and reduced JNK protein expression at IC70 on both cells. Effect of Foslip® PDT on HT29 cells was independent to 5-FU resistance properties. Therefore, Foslip® PDT could be a potential treatment for 5-FU resistant cancer patients. Further investigations on the Foslip® PDT mediated molecular changes in HT29FU cells deserve to be explored.