Melanin-Ce6-loaded polydopamine nanoparticles-based enhanced phototherapy for B16 melanoma cancer cells.

Melanoma is one of the most aggressive and lethal types of cancer owing to its metastatic propensity and chemoresistance property. An alternative therapeutic option is photodynamic and photothermal therapies (PDT/PTT), which employ near-infrared (NIR) light to generate heat and reactive oxygen species (ROS). As per previous reports, Melanin (Mel), and its synthetic analogs (i.e. polydopamine nanoparticles) can induce NIR light-mediated heat energy, thereby selectively targeting and ameliorating cancer cells. Similarly, chlorin e6 (Ce6) also has high ROS generation ability and antitumor activity against various types of cancer. Based on this tenet, In the current study, we have encapsulated Mel-Ce6 in a polydopamine (PDA) nanocarrier (MCP NPs) synthesized by the oxidation polymerization method. The hydrodynamic diameter of the synthesized spherical MCP NPs was 139 ± 10 nm. The MCP NPs, upon irradiation with NIR 690 nm laser for 6 min, showed photothermal efficacy of more than 50 °C. Moreover, the red fluorescence in the MCP NPs due to Ce6 can be leveraged for diagnostic purposes. Further, the MCP NPs exhibited considerable biocompatibility with the L929 cell line and exerted nearly 70% ROS-mediated cytotoxicity on the B16 melanoma cell line after the laser irradiation. Thus, the prepared MCP NPs could be a promising theranostic agent for treating the B16 melanoma cancer.

Ferroptosis boosted oral cancer photodynamic therapy by carrier-free Sorafenib-Ce6 self-assembly nanoparticles.

Oral cancer is a disease with high morbidity and mortality worldwide and greatly impacts the quality of life, especially in patients with advanced stages. Photodynamic therapy (PDT) is one of the most effective clinical treatments for oral cancers. However, most clinically applied photosensitizers have several deficiencies, including oxygen dependence, poor aqueous solubility, and a lack of tumor-targeting ability. Herein, the carrier-free multifunctional Sorafenib (Sor), chlorin e6 (Ce6), and Fe3+ self-assembly co-delivery nanoparticles (Sor-Ce6 NPs) were constructed via combining a ferroptosis inducer Sor and a photosensitizer Ce6 for synergetic therapy. The as-synthesized Sor-Ce6 NPs presented excellent colloidal stability and water dispersity with good in vivo tumor-targeting ability. More significantly, the low dose of Sor-Ce6 NPs had little dark toxicity but produced significantly enhanced ROS and supplied O2 sustainably to increase phototoxicity through ferroptosis pathway. Notably, the Sor-Ce6 NPs showed significantly higher in vitro and in vivo anti-tumor efficacy than the Sor/Ce6 mixture due to the improvement of cellular uptake and the incorporation of foreign Fe ions in the system, which also confer the T1 magnetic resonance-guided imaging ability to the formed Sor-Ce6 NPs. Our study demonstrates a promising self-assembled strategy for overcoming hypoxia-related PDT resistance for oral cancer treatment.

Antitumor Effect of Photodynamic Therapy/Sonodynamic Therapy/Sono-Photodynamic Therapy of Chlorin e6 and Other Applications.

Chlorin e6 (Ce6) has been extensively researched and developed as an antitumor therapy. Ce6 is a highly effective photosensitizer and sonosensitizer with promising future applications in photodynamic therapy, dynamic acoustic therapy, and combined acoustic and light therapy for tumors. Ce6 is also being studied for other applications in fluorescence navigation, antibacterials, and plant growth regulation. Here we review the role and research status of Ce6 in tumor therapy and the problems and challenges of its clinical application. Other biomedical effects of Ce6 are also briefly discussed. Despite the difficulties in clinical application, Ce6 has significant advantages in photodynamic therapy (PDT)/sonodynamic therapy (SDT) against cancer and offers several possibilities in clinical utility.

The synthesis of thermostable, strongly basic Anion-Exchange resins using Cross-Linked biguanide and its application in the extraction of Sodium copper chlorophyllin.

Commercially available, strongly basic anion-exchange resins with quaternary ammonium groups have been widely used in the purification of natural plant extracts. However, under the condition of high temperature (greater than 60 °C), these resins could not be used for long periods because of the Hofmann degradation of the strongly basic groups. In this work, the synthesis of novel, thermally stable, strongly basic resins, which has a cross-link biguanide structure, was reported. The mechanism of thermal degradation was investigated, and the result indicated that not only the stability of the functional group but also the link mode between the functional group and the resin matrix should influence the thermal stability of the resin. In our experiment, the PDG2 resin was selected to separate sodium copper chlorophyllin (SCC), a type of edible pigment derived from plants, due to its optimal thermal stability and adsorption capacity. The adsorption mechanism and thermodynamics of PDG2 were also investigated. The results demonstrated that the main adsorption affinity of PDG2 toward SCC was due to the synergistic effects of the hydrophobic and ionic interactions, and the rise in temperature will benefit the adsorption equilibrium, which differed from the equilibrium for lutein. Therefore, under suitable gradient desorption conditions, a high-purity SCC extract was prepared. After eight cycles, the adsorption capacity of the PDG2 remained constant and reproducible at a high temperature (70 °C).

Oxygen-boosted biomimetic nanoplatform for synergetic phototherapy/ferroptosis activation and reversal of immune-suppressed tumor microenvironment.

Photodynamic therapy (PDT) induces apoptosis of cancer cells by generating cytotoxic reactive oxygen species, the therapeutic effect of which, however, is impeded by intrinsic/inducible apoptosis-resistant mechanisms in cancer cells and hypoxia of tumor microenvironment (TME); also, PDT-induced anti-tumor immunity activation is insufficient. To deal with these obstacles, a novel biomimetic nanoplatform is fabricated for the precise delivery of photosensitizer chlorin e6 (Ce6), hemin and PEP20 (CD47 inhibitory peptide), integrating oxygen-boosted PDT, ferroptosis activation and CD47-SIRPα blockade. Hemin's catalase-mimetic activity alleviates TME hypoxia and enhances PDT. The nanoplatform activates ferroptosis via both classical (down-regulating glutathione peroxidase 4 pathway) and non-classical (inducing Fe2+ overload) modes. Besides the role of hemin in consuming glutathione and up-regulating heme oxygenase-1 expression, interestingly, we observe that Ce6 enhance ferroptosis activation via both classical and non-classical modes. The anti-cancer immunity is reinforced by combining PEP20-mediated CD47-SIRPα blockade and PDT-mediated T cell activation, efficiently suppressing primary tumor growth and metastasis. PEP20 has been revealed for the first time to sensitize ferroptosis by down-regulating system Xc-. This work sheds new light on the mechanisms of PDT-ferroptosis activation interplay and bridges immunotherapy and ferroptosis activation, laying the theoretical foundation for novel combinational modes of cancer treatment.

Near-infrared light and redox dual-activatable nanosystems for synergistically cascaded cancer phototherapy with reduced skin photosensitization.

Currently, activatable photodynamic therapy (PDT) that is precisely regulated by endogenous or exogenous stimuli to selectively produce cytotoxic reactive oxygen species at the tumor site is urgently in demand. Herein, we fabricated a dual-activatable PDT nanosystem regulated by the redox tumor microenvironment and near-infrared (NIR) light-induced photothermal therapy (PTT). In this study, photosensitizer chlorin e6 (Ce6) was conjugated to hyaluronic acid (HA) via a diselenide bond to form an amphiphilic polymer (HSeC) for loading PTT agent IR780 to produce HSeC/IR nanoparticles (NPs). The photoactivity of Ce6 for PDT was "double-locked" by the aggregation-caused quenching (ACQ) effect and the fluorescence resonance energy transfer (FRET) from Ce6 to IR780 during blood circulation. After selective accumulation into tumors, HSeC/IR NPs were subsequently dissociated due to the "double-key", which included diselenide bond dissociation under high redox conditions and IR780 degradation upon NIR laser irradiation, resulting in recovering Ce6. In vitro studies indicated that Ce6 photoactivity in HSeC/IR NPs was significantly suppressed when compared with free Ce6 or in HSeC NPs. Moreover, BALB/c mice treated with HSeC/IR NPs displayed distinctly alleviated skin damage during PDT. Synergetic cascaded PTT-PDT with superior tumor suppression was observed in SCC7 tumor-bearing mice. Therefore, the study findings could provide a promising treatment strategy for PTT-facilitated PDT with high antitumor efficacies and reduced skin phototoxicity levels.

Yolk-shell Fe3O4@Carbon@Platinum-Chlorin e6 nanozyme for MRI-assisted synergistic catalytic-photodynamic-photothermal tumor therapy.

HYPOTHESIS: Tumor treatments based on phototherapy, such as photodynamic therapy (PDT) and photothermal therapy (PTT), are promising anticancer strategies. However, their dependence on light also poses several limitations for their application. Therefore, the establishment of a multifunctional nanotheranostic platform based on light therapy is needed to improve applicability of the technology. EXPERIMENTS: We designed yolk-shell magnetic Fe3O4@Carbon@Platinum-Chlorin e6 nanoparticles (MCPtCe6), which may be used for Magnetic resonance imaging (MRI) and synergistic catalytic-photodynamic-photothermal (catalytic-PDT-PTT) tumor therapy. FINDINGS: We designed to compound multiple nanozymes and solve the drawbacks of single nanozyme and give additional functionalization to nanozymes for tumor therapy. Fe3O4 has T2 weighted MRI ability. The designed yolk-shell structure can disperse Fe3O4 in the carbon shell layer, which in turn can act as a carrier for PtNPs and improve the dispersion of both Fe3O4 and Pt. Pt nanoparticles attached to the surface of N-doped carbon spheres enhanced the catalytic ability of the nanozyme to generate reactive oxygen species (ROS). The covalently linked photosensitizer chlorin e6 (Ce6) on the Fe3O4@C@Pt (MCPt) nanozyme is essential for the therapeutic effects of PDT. MCPtCe6 can be specifically activated by the microenvironment through an enzyme-like catalytic process and extend PDT/PTT in acidic and H2O2-rich microenvironments. The results showed that MCPtCe6 had a high photothermal conversion efficiency (η = 28.28%), indicating its feasibility for PTT. Further cellular and animal studies have revealed that catalytic-PDT-PTT therapy can effectively inhibit tumors both in vitro and in vivo.

Effects of Sodium Chlorophyllin Copper on APO-1 Expression in Bone Marrow Mesenchymal Stem Cells of Rats with Aplastic Anaemia.

Background: Aplastic anaemia (AA) is a highly prevalent blood disorder in the East and Southeast Asian countries, and a proportion of the patients is poorly treated with immunosuppressive agents. This study is aimed at exploring the effects of sodium copper chlorophyllin (SCC) on rats with AA and at providing the theoretical basis for the treatment of AA using traditional Chinese medicine. Methods: A rat model of AA was induced by combining 5-fluorouracil with busulfan, and different groups were treated with 25 mg/kg cyclosporin A (CsA) and low-, medium-, and high-dose SCC (25-, 50-, and 100-mg/kg; L-, M-, and H-SCC, respectively). A comparative analysis of peripheral blood counts, T-cell subsets, cytokine levels, bone marrow pathology, and APO-1 expression in mesenchymal stem cells in each group was conducted. Results: SCC can increase the platelet count and haemoglobin concentration in the peripheral blood of AA rats, whereas bone marrow biopsies revealed that the number of nucleated cells and megakaryocytes of SCC-treated rats increased compared with the model group. This was particularly evident in the H-SCC group. As regards the correction of immune function, unlike CsA, which reduced the absolute CD8+ T-cell count, SCC corrected the imbalanced CD4/CD8 ratio by increasing the absolute CD4+ T-cell count, whereas SCC increased the number of regulatory T-cells and reduced the level of interferon-γ in AA rats. When comparing the expression of APO-1 in the MSCs, results of the reverse-transcriptase polymerase chain reaction and Western blot analysis showed that SCC can increase the expression of APO-1 both at the mRNA and protein levels. Conclusion: We found that SCC can improve haematopoietic function and regress immune disorders in AA rats, which enhanced the expression of APO-1 in bone marrow MSCs. This may be one of the mechanisms of SCC in treating AA.

Evaluation of hepatoprotective effect of Nebivolol and sodium copper Chlorophyllin on CCL4-induced hepatotoxicity in mice.

OBJECTIVE: In this study, the protective effect of sodium copper chlorophyllin and nebivolol was evaluated in a mice model of CCL4 induced hepatotoxicity. Silymarin was used as a traditional hepatoprotective drug. MATERIALS AND METHODS: Thirty (30) mice were used as they were divided into five groups: the first group was the control group which received distilled water + olive oil, the second group which received 1.5 ml/kg of CCl4 diluted in olive oil three times a week, the third group which received CCl4 + Silymarin 50 mg/kg/day, the fourth group which received CCl4 + nebivolol 4 mg/kg/day, and the fifth group which received 1.5 ml/kg of CCl4+ Cu-chlorophyllin 50 mg/kg/day. The drugs were given by intraperitoneal route for 5 weeks. The detection, quantification of CCl4 induced hepatotoxicity and possible protective effect of either silymarin, nebivolol, or sodium copper chlorophyllin were assessed using biochemical analysis of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein, lipid profile, an assay of oxidants and antioxidants, assay of interleukin 6 (IL6) and tumor necrosis factor-alpha (TNF-α), and histopathological examination. RESULTS: The administration of carbon tetrachloride (CCl4) produced pronounced liver impairment. It significantly increased ALT, AST, ALP, malondialdehyde, and serum nitric oxide levels compared to normal control group besides a decrease in total protein, serum catalase, tissue SOD, and GSH levels. IL-6 and TNF-α levels were significantly higher while total cholesterol was significantly lower in mice receiving CCL4 compared to the normal control group. CCL4 induced severe hyperemia and congestion inside the portal area with leukocytic infiltration, hepatic degeneration, and bridge fibrosis. CONCLUSIONS: Co-administration of either silymarin, nebivolol, or sodium copper chlorophyllin with CCl4 was able to ameliorate up to almost contradict CCl4 induced hepatic injury through their anti-inflammatory and antioxidant activities.

A novel therapeutic strategy of multimodal nanoconjugates for state-of-the-art brain tumor phototherapy.

BACKGROUND: The outcome of phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) for glioblastoma multiforme (GBM), is disappointing due to insufficient photoconversion efficiency and low targeting rate. The development of phototherapeutic agents that target GBM and generate high heat and potent ROS is important to overcome the weak anti-tumor effect. RESULTS: In this study, nanoconjugates composed of gold nanoparticles (AuNPs) and photosensitizers (PSs) were prepared by disulfide conjugation between Chlorin e6 (Ce6) and glutathione coated-AuNP. The maximum heat dissipation of the nanoconjugate was 64.5 ± 4.5 °C. Moreover, the proximate conjugation of Ce6 on the AuNP surface resulted in plasmonic crossover between Ce6 and AuNP. This improves the intrinsic ROS generating capability of Ce6 by 1.6-fold compared to that of unmodified-Ce6. This process is called generation of metal-enhanced reactive oxygen species (MERos). PEGylated-lactoferrin (Lf-PEG) was incorporated onto the AuNP surface for both oral absorption and GBM targeting of the nanoconjugate (denoted as Ce6-AuNP-Lf). In this study, we explored the mechanism by which Ce6-AuNP-Lf interacts with LfR at the intestinal and blood brain barrier (BBB) and penetrates these barriers with high efficiency. In the orthotopic GBM mice model, the oral bioavailability and GBM targeting amount of Ce6-AuNP-Lf significantly improved to 7.3 ± 1.2% and 11.8 ± 2.1 µg/kg, respectively. The order of laser irradiation, such as applying PDT first and then PTT, was significant for the treatment outcome due to the plasmonic advantages provided by AuNPs to enhance ROS generation capability. As a result, GBM-phototherapy after oral administration of Ce6-AuNP-Lf exhibited an outstanding anti-tumor effect due to GBM targeting and enhanced photoconversion efficiency. CONCLUSIONS: The designed nanoconjugates greatly improved ROS generation by plasmonic crossover between AuNPs and Ce6, enabling sufficient PDT for GBM as well as PTT. In addition, efficient GBM targeting through oral administration was possible by conjugating Lf to the nanoconjugate. These results suggest that Ce6-AuNP-Lf is a potent GBM phototherapeutic nanoconjugate that can be orally administered.

Enhanced ROS-Boosted Phototherapy against Pancreatic Cancer via Nrf2-Mediated Stress-Defense Pathway Suppression and Ferroptosis Induction.

In situ oxygen generation is the most common strategy to boost reactive oxygen species (ROS) for enhancing the efficacy of phototherapy in cancer, including photodynamic therapy (PDT) and photothermal therapy (PTT). However, hyperoxidation or hyperthermia often triggers stress-defense pathways and promotes tumor cell survival, thus severely limiting the therapeutic efficacy. To overcome the tumor hypoxia and thermal resistance existing in phototherapy, we constructed a self-synergistic nanoplatform for tumors by incorporating brusatol, a nuclear factor erythroid 2-related factor (Nrf2) inhibitor, into the silica nanonetwork. It was then sequentially decorated with MnO2 and the photosensitizer chlorin e6 (Ce6) and then coated with poly(ethylene glycol)-folate (PEG-FA)-functionalized polydopamine (PDA) (designated as brusatol/silica@MnO2/Ce6@PDA-PEG-FA). As an oxygen generator, MnO2 can promote ROS production, which not only directly enhances Ce6-mediated PDT but also strengthens PDA-mediated PTT by attacking heat shock proteins (HSPs). Particularly, brusatol could efficiently inhibit the activation of Nrf2 defense pathway under hyperoxidation and hyperthermia and cause glutathione peroxidase 4 (GPX4) and ferritin heavy chain (FTH) inactivation, thereby inducing ferroptosis and ultimately enhancing the phototherapeutic effects. By exploiting these features, brusatol/silica@MnO2/Ce6@PDA-PEG-FA exhibited excellent antitumor efficacy with enhanced PDT and PTT both in in vitro and in vivo studies. Overall, our work highlights a promising strategy against hypoxia- and hyperthermia-associated resistance in phototherapy via suppressing stress-defense system and inducing ferroptosis.

Transforming a Sword into a Knife: Persistent Phototoxicity Inhibition and Alternative Therapeutical Activation of Highly-Photosensitive Phytochlorin.

The phototoxicity of photosensitizers (PSs) is a double-edged sword with one edge beneficial for destroying tumors while the other is detrimental to normal tissues, and the conventional "OFF-ON" strategy provides temporary inhibition so that phototoxicity would come sooner or later due to the inevitable retention and transformation of PSs in vivo. We herein put forward a strategy to convert "double-edged sword" PSs into "single-edged knife" ones with simultaneously persistent phototoxicity inhibition and alternative multiple therapeutical activation. The Chlorin e6 (Ce6) as the PS model directly assembles with Cu2+ ions into nanoscale frameworks (nFs) whose Cu2+-coordination includes both carboxyl groups and a porphyrin ring of Ce6 instead of Fe3+/Mn2+-coordination with only carboxyl groups. Compared to the high phototoxicity of Ce6, the nFs exhibit efficient energy transfer due to the dual-coordination of paramagnetic Cu2+ ions and the aggregation, achieving the persistent and high phototoxicity inhibition rate of >92%. Alternatively, the nFs not only activate a high photoacoustic contrast and near-infrared (NIR)-driven photothermal efficacy (3.5-fold that of free Ce6) due to the aggregation-enhanced nonradiative transition but also initiate tumor microenvironment modulation, structure disassembly, and chemodynamic effect by Cu2+ ions. Given these merits, the nFs achieve long-term biosecurity, no retina injury under sunlight, and a higher therapeutical output than the photodynamic effect of Ce6. This work presents a possibility of converting numerous highly phototoxic porphyrins into safe and efficient ones.

Photo-Driven Delivery of 125I-Labeled Nanomicelles for Nucleus-Targeted Internal Conversion Electron-Based Cancer Therapy.

As a kind of high linear energy transfer (LET) radiation, internal conversion electrons are emitted from some radionuclides, such as 125I, triggering severe DNA damage to tumor cells when transported into the nucleus. Herein, we develop a curcumin-loaded nanomicelle composed of a photosensitizer chlorin e6 (Ce6) and amphiphilic poly(ethylene glycol) (poly(maleic anhydride-alt-1-octadecene)-poly(ethylene glycol) (C18-PMH-PEG)) to deliver 125I into the nucleus under 660 nm laser irradiation, leading to the optimized imaging-guided internal conversion electron therapy of cancer. Ce6-containing nanomicelles (Ce6-C18-PEG) self-assemble with nucleus-targeted curcumin (Cur), obtaining Ce6-C18-PEG/Cur nanoparticles. After labeling Cur with 125I, Ce6-C18-PEG/Cur enables single-photon emission computed tomography and fluorescence imaging of the tumor, serving as a guide for follow-up laser irradiation. Notably, the 660 nm laser-triggered photodynamic reaction of Ce6 optimizes the delivery of Ce6-C18-PEG/125I-Cur at various stages, including tumor accumulation, cellular uptake, and lysosome escape, causing plenty of 125I-Cur to enter the nucleus. By this strategy, Ce6-C18-PEG/125I-Cur showed optimal antitumor efficacy and high biosafety in mice treated with local 660 nm laser irradiation using efficient energy deposition of internally converted electrons over short distances. Therefore, our work provides a novel strategy to optimize 125I delivery for tumor treatment.

A nanosensitizer self-assembled from oleanolic acid and chlorin e6 for synergistic chemo/sono-photodynamic cancer therapy.

BACKGROUND: Sono-photodynamic therapy (SPDT) which is the combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT), could exert much better anti-cancer effects than monotherapy. The combination of chemotherapy and PDT or SDT has shown great potential for cancer treatment. However, the combination of SPDT and chemotherapy for cancer treatment is rarely explored. PURPOSE: We utilized a natural hydrophobic anti-cancer drug oleanolic acid (OA) and a photosensitizer chlorin e6 (Ce6) through self-assembly technology to form a carrier-free nanosensitizer OC for combined chemotherapy and SPDT for cancer treatment. No studies involving using carrier-free nanomedicine for combined chemotherapy/SPDT have been reported yet. STUDY DESIGN: After fully characterization of OC, the in vitro and in vivo anti-cancer activities of OC were investigated and the mechanisms of the synergistic therapeutic effects were studied. METHODS: OC were synthesized through self-assembly technology and characterized by dynamic light scattering (DLS) and an atomic force microscope (AFM). Confocal microscope was used to investigate the intracellular uptake efficiency and the penetration ability of OC. The cell viability of PC9 and 4T1 cells treated with OC under laser and ultrasound (US) irradiation was determined by MTT assay. Furthermore, flow cytometry was performed to detect the reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential (MMP), cell apoptosis and cell cycle arrest. Finally, the anti-tumor therapeutic efficacy of OC was investigated in orthotopic 4T1 breast tumor-bearing mouse model. RESULTS: OC showed an average particle size of around 100 nm with excellent light stability. OC increased more than 23 times accumulation of Ce6 in cancer cells and had strong tumor penetration ability in three-dimensional (3D) multicellular tumor spheroids (MCTSs). Compared with other therapeutic options, OC showed obvious synergistic inhibitory effects under light and US irradiation in PC9 and 4T1 cells with a significant decrease in IC50 values. Mechanism studies showed that OC could generate high ROS, induce MMP loss, and cause apoptosis and cell cycle arrest. In vivo studies also approved the synergistic therapeutic effects of OC in 4T1 mouse models. CONCLUSION: Self-assembled carrier-free nanosensitizer OC could be a promising therapeutic agent for synergistic chemo/sono-photodynamic therapy for cancer treatment.

Self-delivery nanomedicine for chemotherapy sensitized photodynamic therapy.

A chlorine e6 (Ce6) and curcumin (Cur) based self-delivery nanomedicine (CeCu) is prepared for chemotherapy sensitized photodynamic therapy (PDT). The chemotherapeutic agent of Cur could inhibit the TrxR activity to destroy the cellular ROS-defence system for enhanced PDT, which provides synergistic effects for tumor precision therapy in consideration of the unfavorable tumor microenvironments.

Anisotropic Truncated Octahedral Au with Pt Deposition on Arris for Localized Surface Plasmon Resonance-Enhanced Photothermal and Photodynamic Therapy of Osteosarcoma.

The multifunctional combined nanoplatform has a wide application prospect in the synergistic treatment of cancer. Nevertheless, the traditional treatment of phototherapy is limited by the catalytic nanomaterial itself, so the effect is not satisfactory. Here, the arris of the anisotropic truncated octahedral Au (TOh Au) was coated with noble metal Pt to form a spatial separation structure, which enhanced the local surface plasmonic resonance and thus boosted the photocatalytic effect. In this system, the highly efficient photocatalysis provides a strong guarantee for oncotherapy. On the one hand, the structure of arris deposition adequately improves the efficiency of photothermal conversion, which substantially improves the effectiveness of photothermal therapy. On the other hand, in situ oxygen production of Pt ameliorates tumor hypoxia, and through the O2 self-production and sales mode, the growth and development of tumor were inhibited. Meanwhile, under the enhanced photocatalysis, more O2 were produced, which greatly evolved the treatment effect of photodynamic therapy. In the end, the addition of hyaluronic acid can specifically target osteosarcoma cells while improving the retention time and biocompatibility of the material in the body. Thus, the nanocomposite shows superexcellent synergistic enhancement of photothermal conversion efficiency and photodynamic capability in vitro and in vivo, which provides a potential possibility for osteosarcoma cure.

Synthesis of iridium-based nanocomposite with catalase activity for cancer phototherapy.

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted attention due to its enhanced tumor therapy effect. This study proposes a novel nanoenzyme-based theranostic nanoplatform, IrO2@MSN@PDA-BSA(Ce6), for the combined PTT and PDT of tumors. IrO2 was prepared by a simple hydrolysis method and coated with a thin layer of mesoporous silica (MSN) to facilitate the physical adsorption of Chlorin e6 (Ce6). The PDA coating and IrO2 NPs of the nanoplatform demonstrated an improved photothermal conversion efficiency of 29.8% under NIR irradiation. Further, the Ce6 loading imparts materials with the ability to produce reactive oxygen species (ROS) under 660 nm NIR laser irradiation. It was also proved that the IrO2 NPs could catalyze the hydrogen peroxide (H2O2) in the tumor microenvironment (TME) to generate endogenous oxygen (O2), thereby enhancing the efficiency of PDT. The in vitro and in vivo experiments indicated that the nanocomposite was highly biocompatible and could produce a satisfactory tumor therapeutic effect. Thus, the findings of the present study demonstrate the viability of using theranostic nanoenzymes for translational medicine.

Oxygen-generating glycol chitosan-manganese dioxide nanoparticles enhance the photodynamic effects of chlorin e6 on activated macrophages in hypoxic conditions.

This study aimed to investigate the use of glycol chitosan (GC) for the synthesis of MnO2 nanoparticles (NPs) and to evaluate whether the prepared GC-MnO2 NPs enhance the light-triggered photodynamic effects of chlorin e6 (Ce6) via the generation of oxygen and alleviation of hypoxia in lipopolysaccharide (LPS)-activated macrophages (RAW 264.7), which produce excessive amounts of reactive oxygen species (ROS). GC-MnO2 NPs were synthesized by a simple reaction between GC and KMnO4 in water. The prepared GC-MnO2 NPs were spherical in shape, with a mean diameter of approximately 60 nm. The particles effectively generated oxygen via H2O2-induced degradation under hypoxic conditions, which led to an increase in the singlet oxygen levels upon laser irradiation. Furthermore, GC-MnO2 NPs significantly enhanced the light-triggered photodynamic effects of Ce6 on activated macrophages under hypoxic conditions, as shown by the increased levels of cell death and cell membrane damage in activated macrophages. Therefore, these results suggest that GC can be used as an alternative natural polymer for the synthesis of MnO2 NPs and that oxygen-generating GC-MnO2 NPs enhance the light-triggered photodynamic effects of Ce6 on activated macrophages by alleviating hypoxia.

A Gd-doped polydopamine (PDA)-based theranostic nanoplatform as a strong MR/PA dual-modal imaging agent for PTT/PDT synergistic therapy.

Based on widely used photoacoustic imaging (PAI) and photothermal properties of polydopamine (PDA), a multifunctional Gd-PDA-Ce6@Gd-MOF (GPCG) nanosystem with a core-shell structure and strong imaging ability was constructed. Benefitting from the metal-organic framework (MOF) structure, GPCG nanoparticles (NPs) showed enhanced magnetic resonance imaging (MRI) ability with high relaxation rates (r1 = 13.72 mM-1 s-1 and r2 = 216.14 mM-1 s-1). The MRI effect of Gd ions combined with the PAI effect of PDA, giving GPCG NPs a dual-modal imaging ability. The core, mainly composed of PDA and photodynamic photosensitizer chlorin e6 (Ce6), achieved photothermal/photodynamic therapy (PTT/PDT) synergistic performance. Besides, to overcome the unexpected release of Ce6, the MOF shell realized pH-sensitive release and a high local concentration. Through in vivo studies, we concluded that GPCG NPs show a good inhibitory effect on tumor growth. In conclusion, we successfully obtained a GPCG theranostic nanoplatform and paved the way for subsequent design of imaging guided therapeutic nanostructures based on metal-doped PDA.

2D LDH-MoS2 clay nanosheets: synthesis, catalase-mimic capacity, and imaging-guided tumor photo-therapy.

Owing to the hypoxia status of the tumor, the reactive oxygen species (ROS) production during photodynamic therapy (PDT) of the tumor is less efficient. Herein, a facile method which involves the synthesis of Mg-Mn-Al layered double hydroxides (LDH) clay with MoS2 doping in the surface and anionic layer space of LDH was presented, to integrate the photo-thermal effect of MoS2 and imaging and catalytic functions of Mg-Mn-Al LDH. The designed LDH-MoS2 (LMM) clay composite was further surface-coated with bovine serum albumin (BSA) to maintain the colloidal stability of LMM in physiological environment. A photosensitizer, chlorin e6 (Ce6), was absorbed at the surface and anionic layer space of LMM@BSA. In the LMM formulation, the magnetic resonance imaging of Mg-Mn-Al LDH was enhanced thanks to the reduced and acid microenvironment of the tumor. Notably, the ROS production and PDT efficiency of Ce6 were significantly improved, because LMM@BSA could catalyze the decomposing of the overexpressed H2O2 in tumors to produce oxygen. The biocompatible LMM@BSA that played the synergism with tumor microenvironment is a promising candidate for the effective treatment of cancer.