Photodynamic Efficiency Research Articles

Staphylococcus aureus photodynamic inactivation mechanisms by rose bengal: use of antioxidants and spectroscopic study

This study aims to follow the photodynamic and spectroscopic properties of dianionic rose Bengal disodium salt (RB) on Staphylococus aureus (S. aureus) in phosphate buffer solution (PBS) at pH 7.3. It focused on: (1) the effect of several reactive oxygen species (ROS) antioxidants used [such as sodium azide (NaN3), l-tryptophan (l-Trp) and d-mannitol] on the RB photodynamic efficiency as a mean to identify the main ROS attributed, and (2) the possible interactions of the RB with the important singlet oxygen quencher used namely tryptophan and/or between the dye and the bacteria S. aureus thanks to a spectroscopic study. The results showed that 20 µM of RB and 10 min of visible light (50 mW/cm2) with a light fluence dose of 30 J/cm2 are crucial for a good photodynamic action, achieving a reduction of 79.4% in the viability. Rose Bengal photodynamic action was in part inhibited by D-mannitol and l-Trp, indicating the mediation by.OH and 1O2, respectively. The high inhibition of the RB activity against S. aureus by l-Trp is not due only to its singlet oxygen quencher ability but it is mainly due to the interaction between RB and l-Trp as shown spectrophotometrically.

Titania and silica nanoparticles coupled to Chlorin e6 for anti-cancer photodynamic therapy.

In this study, light-sensitive photosensitizers (Chlorin e6, Ce6) were linked to TiO2 and SiO2 nanoparticles (NPs) in order to develop new kinds of NP-based drug delivery systems for cancer treatment by PDT. TiO2 or SiO2 NPs were modified either by the growth of a polysiloxane layer constituted of two silane reagents ((3-aminopropyl)triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS)) around the core (PEGylated NPs: TiO2@4Si-Ce6-PEG, SiO2@4Si-Ce6-PEG) or simply modified by APTES alone (APTES-modified NPs: TiO2-APTES-Ce6, SiO2-APTES-Ce6). Ce6 was covalently attached onto the modified TiO2 and SiO2 NPs via an amide bond. The absorption profile of the hybridized NPs was extended to the visible region of the light. The physicochemical properties of these NPs were explored by TEM, HR-TEM, XRD, FTIR and zeta potential. The photophysical characteristics including the light absorption, the fluorescence properties and the production reactive oxygen species (1O2 and HO) were also addressed. In vitro experiments on glioblastoma U87 cells were performed to evaluate the photodynamic efficiency of the new hybridized NPs. The cells were exposed to different concentrations of NPs and illuminated (λexc = 652 nm, fluence rate 10 J/cm2). In contrast to the PEGylated NPs, the APTES-modified nanosystems were found to be more efficient for PDT. An interesting photodynamic effect was observed in the case of TiO2-APTES-Ce6 NPs. After illumination, the viability of U87 was decreased by 89% when they were exposed to 200 μg/mL of TiO2-APTES-Ce6 NPs, which corresponds to 0.22 μM of Ce6. The same effect can be obtained with free photosensitizer but using a higher concentration of 10 μM of Ce6.

Towards optimisation of surface enhanced photodynamic therapy of breast cancer cells using gold nanoparticle-photosensitiser conjugates.

Gold nanoparticles (AuNPs; ca. 4 nm) were synthesised and functionalised with a mixed monolayer of polyethylene glycol (PEG) and one of two zinc phthalocyanines (ZnPcs), the difference between the two molecules was the length of the carbon chain that connects the Pc to the gold core. The chain was composed of either three (C3Pc) or eleven (C11Pc) carbon atoms. The C11Pc photosensitiser displayed higher fluorescence emission intensity than the C3Pc in solution. By contrast, the C3Pc photosensitiser exhibited higher fluorescence when bound to the surface of the AuNPs than the C11Pc, despite the shorter carbon chain which was expected to quench the fluorescence. In addition, the C3Pc nanoparticle conjugates exhibited an enhancement in the production of singlet oxygen (1O2). The metal-enhanced 1O2 production led to a remarkable photodynamic efficacy for the treatment of human breast cancer cells.

Hypericin Loaded Liposomes for Anti‐Microbial Photodynamic Therapy of Gram‐Positive Bacteria

Due to its highly lipophilic nature, poor solubility in aqueous media, and poor bioavailability, the naturally occurring photosensitizer hypericin has a limited therapeutic value. Liposomal encapsulation is a promising solution to overcome these limitations. Use of liposomes as delivery vehicles for hypericin in antimicrobial photodynamic therapy (aPDT) is quite new. The aim of this work is therefore, to prepare various hypericin loaded liposomal formulations viz. DOPE/CHEMS/DPPC, DSPC/DPPC/DSPE‐PEG, and DPPC/DOTAP. The formulations are physicochemically characterized and tested for their binding affinity toward bacteria and for their photodynamic efficiency. All formulations achieve a 2.3–2.5 log reduction of Staphylococcus saprophyticus subsp. bovis and facilitate the binding and uptake of the photosensitizer through the bacterial cell wall.

Synthesis, spectroscopic studies and biological evaluation of acridine derivatives: The role of aggregation on the photodynamic efficiency

Two new photoactive compounds (1 and 2) derived from the 9-amidoacridine chromophore have been synthesized and fully characterized. Their abilities to produce singlet oxygen upon irradiation have been compared. The synthesized compounds show very different self-aggregating properties since only 1 present a strong tendency to aggregate in water. Biological assays were conducted with two cell types: hepatoma cells (Hep3B) and human umbilical vein endothelial cells (HUVEC). Photodynamic therapy (PDT) studies carried out with Hep3B cells showed that non-aggregating compound 2 showed photoxicity, ascribed to the production of singlet oxygen, being aggregating compound 1 photochemically inactive. On the other hand suspensions of 1, characterized as nano-sized aggregates, have notable antiproliferative activity towards this cell line in the dark.

Naphthalocyanine as a New Photothermal Actuator for Lipid-Based Drug Delivery Systems.

One approach to address the substantial global burden of ocular diseases such as aged related macular degeneration is using light-activated drug delivery to obviate the need for highly invasive and frequent, costly intravitreal injections. To enable such systems, new light responsive materials are required. This communication reports the use of silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (SiNC), a small molecule photosensitizer, as a new actuator for triggering light responsive lipid-based drug delivery systems. Small-angle X-ray scattering was used to confirm that the addition of SiNC imparted light sensitivity to the lipid systems, resulting in a complete phase transition within 20 s of near-infrared irradiation. The phase transition was also reversible, suggesting the potential for on-demand drug delivery. When compared to the phase transitions induced using alternative light responsive actuators, gold nanorods and graphene, there were some differences in phase behavior. Namely, the phytantriol with SiNC system transitioned directly to the inverse micellar phase, skipping the intermediate inverse hexagonal structure. The photodynamic properties and efficiency in controlling the release of drug suggest that SiNC-actuated lipid systems have the potential to reduce the burden of repeated intravitreal injections.

Carbon-1 versus Carbon-3 Linkage of d-Galactose to Porphyrins: Synthesis, Uptake, and Photodynamic Efficiency.

The use of glycosylated compounds is actively pursued as a therapeutic strategy for cancer due to the overexpression of various types of sugar receptors and transporters on most cancer cells. Conjugation of saccharides to photosensitizers such as porphyrins provides a promising strategy to improve the selectivity and cell uptake of the photosensitizers, enhancing the overall photosensitizing efficacy. Most porphyrin-carbohydrate conjugates are linked via the carbon-1 position of the carbohydrate because this is the most synthetically accessible approach. Previous studies suggest that carbon-1 galactose derivatives show diminished binding since the hydroxyl group in the carbon-1 position of the sugar is a hydrogen bond acceptor in the galectin-1 sugar binding site. We therefore synthesized two isomeric porphyrin-galactose conjugates using click chemistry: one linked via the carbon-1 of the galactose and one linked via carbon-3. Free base and zinc analogs of both conjugates were synthesized. We assessed the uptake and photodynamic therapeutic (PDT) activity of the two conjugates in both monolayer and spheroidal cell cultures of four different cell lines. For both the monolayer and spheroid models, we observe that the uptake of both conjugates is proportional to the protein levels of galectin-1 and the uptake is suppressed after preincubation with an excess of thiogalactose, as measured by fluorescence spectroscopy. Compared to that of the carbon-1 conjugate, the uptake of the carbon-3 conjugate was greater in cell lines containing high expression levels of galectin-1. After photodynamic activation, MTT and lactate dehydrogenase assays demonstrated that the conjugates induce phototoxicity in both monolayers and spheroids of cancer cells.

Effect of LaF3: Ag fluorescent nanoparticles on photodynamic efficiency and cytotoxicity of Protoporphyrin IX photosensitizer

LaF3: Ag nanoparticles (NPs) were synthesized by the co-precipitation method. The produced NPs were characterized by X-ray diffraction (XRD) pattern, scanning electron microscope (SEM), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). The emission spectrum of LaF3:Ag NPs is mostly overlapped with the absorption band of protoporphyrin IX (PpIX) and their conjugation was confirmed by studying fluorescence resonance energy transfer (FRET) from LaF3:Ag donor to protoporphyrin IX acceptor. The energy transfers from LaF3:Ag NPs to photosensitizer molecules is very efficient. So, the produced LaF3:Ag NPs can be recommended as light source for photodynamic therapy (PDT). The thiol group of cysteine was bound to LaF3:Ag NPs in order to conjugate LaF3:Ag NPs and protoporphyrin IX. UVC light source was used to excite fluorescent LaF3:Ag NPs. The reactive oxygen species (ROS) produced by photosensitizer was identified using special fluorescent probes (anthracene, methylene blue and methyl orange) as detectors.

Synthesis and biological characterization of novel rose bengal derivatives with improved amphiphilicity for sono-photodynamic therapy

Sono-Photodynamic therapy (SPDT) utilizing ultrasound and light has been demonstrated that this novel approach can lower dosage resulting in reduction of the potential side effects caused by sensitizers. Recently, a new formulation of rose bengal (RB) as an intralesional injection has completed clinical trials phase II for PDT treatment of melanoma cancer. However, the inherent unfavorable pharmacological properties of RB hindered its extensive clinical development. With the aim to identify new RB derivatives (RBDs) with enhanced photodynamic and sonodynamic anticancer efficiency, a series of amphiphilic RBDs have been designed, synthesized and biological characterized. Among them, RBD4 significantly improved cellular uptake and enhanced intracellular ROS generation efficiency upon light and ultrasound irradiation, resulting in dramatically improved anticancer potency. Notably, RBD4 has a relative potency similar to sinoporphyrin sodium (DVDMS), indicating its further potential application for SPDT.

Improved photodynamic effect through encapsulation of two photosensitizers in lipid nanocapsules.

Photodynamic therapy (PDT) has developed into a new clinical and non-invasive treatment for cancer over the past 30 years. By the combination of three non-toxic partners, i.e. a photosensitizer (PS), molecular oxygen (O2) and light, cytotoxic reactive oxygen species (ROS) are locally produced leading to irreversible vascular and cellular damage. In the present study, we report for the first time that the combination of two photosensitizers (2 PSs: Protoporphyrin IX, PpIX and Hypericin, Hy) loaded in the same lipid nanocapsules (LNCs) leads to enhanced photodynamic therapy efficiency when compared with previously reported systems. The 2 PS-loaded LNCs are shown to increase the in vitro phototoxicity at the nanomolar range (IC50 = 274 and 278 nM on HeLa and MDA-MB-231 cell lines, respectively), whereas the corresponding single PS-loaded LNCs at the same concentration exhibit a phototoxicity two times lower. Intracellular localization in HeLa cells indicates a subcellular asymmetry of PpIX and Hy, in the plasma, ER membranes and round internal structures. The biodistribution of LNCs was studied upon different routes of injection into Swiss nude mice; based on the obtained data, LNCs were injected intratumorally and used to slow the growth of xenograft tumors in mice. The results obtained in this study suggest that the combination of two or more PSs may be a promising strategy to improve the efficacy of conventional photodynamic therapy as well as to reduce dark toxicity.

NIRF/PA/CT multi-modality imaging guided combined photothermal and photodynamic therapy based on tumor microenvironment-responsive nanocomposites.

In this study, we developed a novel chitosan (CS)-controlled and aluminum phthalocyanine chloride (AlPc)-loaded molybdenum disulfide (MoS2) nanocomposite as a single nanoplatform (AlPc-MoS2@SiO2-CS) for near-infrared fluorescence (NIRF), photoacoustic (PA), and X-ray computed tomography (CT) multi-modality imaging-guided photothermal and photodynamic combination therapy of tumors. The MoS2 nanodot was used as the PA/CT contrast as well as hyperthermal agent. The MoS2@SiO2 nanoparticles prepared by a facile one-pot approach can serve as drug-delivery vehicles to transport the NIR absorbing photosensitizer AlPc within the mesoporous cavities. Meanwhile, a natural cationic polysaccharide, CS, was introduced as a gatekeeper to avoid the premature release of loaded AlPc. What's more, CS as a tumor microenvironment-responsive agent can control the release of loaded drugs to the acidic local environment in the tumor. The in vivo multimodal imaging uncovered that the AlPc-MoS2@SiO2-CS nanocomposites showed enhanced tumor uptake and diagnosis abilities after intravenous injection. More importantly, the nanocomposites exhibited an evident near-infrared induced photothermal effect in the in vitro and in vivo experiments, which remarkably improved the photodynamic therapy efficiency by accelerating the blood flow and subsequently increasing oxygen supply in the tumor. Taken together, our current work demonstrated a nanoplatform for multimodal imaging guided targeted dual-therapy, which revealed a potential strategy for tumor treatment.

Polymer ligand-assisted fabrication of multifunctional and redox-responsive self-assembled magnetic nanoclusters for bimodal imaging and cancer treatment.

Multifunctional nanoplatforms that can combine diagnostic functions and therapeutic capabilities are highly required for the construction of novel cancer diagnosis-therapy integrative systems. In this work, we developed multifunctional and tumor redox-responsive magnetic nanoclusters (RMNs) by the self-assembly of iron oxide nanoparticles with a chlorin e6 (Ce6)-disulfide-linked polymer ligand. The core of RMNs could enhance the T2-weighted MR contrast capability, and the surface ligand could improve the system stability and load Ce6. In addition, the obtained RMNs also exhibited excellent biocompatibility and higher cytotoxicity upon near infrared (NIR)-irradiation. These RMNs with a size of ∼90 nm can effectively facilitate their accumulation in tumor sites through the enhanced permeability and retention (EPR) effect and subsequently are endocytosed into a highly reductive intracellular environment that activates fluorescence and photodynamic therapeutic antitumor activity. Furthermore, the in vivo imaging and therapy results not only confirmed that RMNs can as bimodal imaging probes for the early-stage diagnosis of cancer but also demonstrated the superior photodynamic therapeutic efficiency of RMNs in suppressing tumor growth. These results indicated that RMNs show great potential for simultaneous diagnostic imaging and photodynamic therapy.

Synthesis and Investigation of Photophysical and Biological Properties of Novel S-Containing Bacteriopurpurinimides.

Novel hybrid molecule containing 2-mercaptoethylamine was synthesized starting from O-propyloxime-N-propoxy bacteriopurpurinimide (dipropoxy-BPI), which was readily oxidized in oxygen atmosphere yielding the corresponding disulfide analogue (disulfide-BPI). Spectral, photophysical, photodynamic, and biological properties of compound were properly evaluated. Compounds bearing disulfide moiety can directly interact with glutathione (GSH), thereby reducing its intracellular concentration. Indeed, mice sarcoma S37 cell line was treated in vitro with disulfide-BPI, yielding a CC50 value of 0.05 ± 0.005 μM. A relatively high level of singlet oxygen was detected. It was demonstrated (by fluorescence) that the PS was rapidly accumulated in a cancer nest (S37) at a relatively high level after 2 h upon intravenous administration. After 24 h, no traces of the molecule were detected in the tumor mass. Moreover, high photodynamic efficiency was demonstrated at doses of 150-300 J/cm2 against two different in vivo tumor models, achieving 100% regression of cancer growth.

Improved photodynamic efficiency for methylene blue from silica-methylene blue@tannic acid-Fe(III) ions complexes in aqueous solutions

To avoid multidrug resistance and tumour recurrence, photodynamic therapy (PDT) was emerging as an alternative therapy and its efficiency was related to photosensitizer (PS) efficiency, oxygen concentration and light characteristic. Methylene blue (MB) molecules as PSs were loaded in silica (silica-MB) and followed by encapsulation by coordination complexes of tannic acid (TA) and Fe(III) ions. In comparison with those of silica-MB, decreased condensation of Si-O-Si, shifted infrared absorbance frequencies of chemical bands, delayed thermal degradation and modulated release behavior of MB were observed for silica-MB@TA with a core–shell structure. Although MB dimers were dominantly released from silica-MB, release of MB monomers from silica-MB@TA was significantly promoted, which was described by the Higuchi model. The promotion of release of MB monomers from silica-MB@TA indicated the well control of aggregate states of MB by the encapsulation of TA and Fe(III) ions complexes. Through monitoring the oxidation of uric acid, generation efficiency of singlet oxygen (1O2) by MB released from silica-MB@TA was fairly higher than that from silica-MB. A facile method to encapsulate silica-MB with complexes of TA and Fe(III) ions was herein demonstrated to raise the generation efficiency of singlet oxygen.

Mitochondria-targeted cationic porphyrin-triphenylamine hybrids for enhanced two-photon photodynamic therapy

The proof of concept for two-photon activated photodynamic therapy has already been achieved for cancer treatment but the efficiency of this approach still heavily relies on the availability of photosensitizers combining high two-photon absorption and biocompatibility. In this line we recently reported on a series of porphyrin-triphenylamine hybrids which exhibit high singlet oxygen production quantum yield as well as high two-photon absorption cross-sections but with a very poor cellular internalization. We present herein new photosensitizers of the same porphyrin-triphenylamine hybrid series but bearing cationic charges which led to strongly enhanced water solubility and thus cellular penetration. In addition the new compounds have been found localized in mitochondria that are preferential target organelles for photodynamic therapy. Altogether the strongly improved properties of the new series combined with their specific mitochondrial localization lead to a significantly enhanced two-photon activated photodynamic therapy efficiency.

ABCG2-mediated suppression of chlorin e6 accumulation and photodynamic therapy efficiency in glioblastoma cell lines can be reversed by KO143

BackgroundPhotodynamic therapy (PDT) of malignant brain tumors is a promising adjunct to standard treatment, especially if tumor stem cells thought to be responsible for tumor progression and therapy resistance were also susceptible to this kind of treatment. However, some photosensitizers have been reported to be substrates of ABCG2, one of the membrane transporters mediating resistance to chemotherapy. Here we investigate, whether inhibition of ABCG2 can restore sensitivity to photosensitizer chlorin e6-mediated PDT. MethodsAccumulation of chlorin e6 in wild type U87 and doxycycline-inducible U251 glioblastoma cells with or without induction of ABCG2 expression or ABCG2 inhibition by KO143 was analyzed using flow cytometry. In U251 cells, ABCG2 was inducible by doxycycline after stable transfection with a tet-on expression plasmid. Tumor sphere cultivation under low attachment conditions was used to enrich for cells with stem cell-like properties. PDT was done on monolayer cell cultures by irradiation with laser light at 665nm. ResultsElevated levels of ABCG2 in U87 cells grown as tumor spheres or in U251 cells after ABCG2 induction led to a 6-fold lower accumulation of chlorin e6 and the light dose needed to reduce cell viability by 50% (LD50) was 2.5 to 4-fold higher. Both accumulation and PDT response can be restored by KO143, an efficient non-toxic inhibitor of ABCG2. ConclusionGlioblastoma stem cells might escape phototoxic destruction by ABCG2-mediated reduction of photosensitizer accumulation. Inhibition of ABCG2 during photosensitizer accumulation and irradiation promises to restore full susceptibility of this crucial tumor cell population to photodynamic treatment.

Tetracarboxy-phthalocyanines: From excited state dynamics to photodynamic inactivation against Bovine herpesvirus type 1

Herein we present the excited state dynamic of zinc and aluminum tetracarboxy-phthalocyanines (ZnPc and AlPc) and its application in the photodynamic inactivation (PDI) of Bovine herpesvirus type 1 (BoHV-1) in vitro. The excited state dynamic provides valuable data to describe the excited state properties of potential optical limiters and/or photosensitizers (PSs), such as: the excited state cross-sections, fluorescence lifetime and triplet state quantum yield. The excited state characterization was performed using three different Z-scan techniques: Single Pulse, White Light Continuum and Pulse Train. Considering the photodynamic inactivation of BoHV-1, an initial viral suspension containing 105.75TCID50/mL was incubated with the PSs for 1h at 37°C under agitation and protected from light. The samples were placed in microtiter plates and irradiated (180mW/cm2). During irradiation, a sample was taken every 15min and the viability of the virus was evaluated. The results show that both phthalocyanines were efficient against viruses. However, a higher photodynamic efficiency was observed by ZnPc, which can be attributed to its higher triplet and singlet quantum yields. The results presented here are important for animal health (treatment of BoHV-1) and also open up a field of studies to use AlPc and ZnPc as potential agents against a wide range of microorganisms of veterinary interest.

Tumor‐Targeting Photothermal Heating‐Responsive Nanoplatform Based on Reduced Graphene Oxide/Mesoporous Silica/Hyaluronic Acid Nanocomposite for Enhanced Photodynamic Therapy

AbstractThis study herein develops a novel tumor‐targeting photothermal heating‐responsive nanoplatform for enhanced photodynamic therapy (PDT). The nanoplatform is prepared by using dopamine‐reduced graphene oxide nanosheets (rGO‐PDA) to enhance photothermal ability, mesoporous silica coated on the rGO‐PDA surface to load drug, and hyaluronic acid to act as gate keeper as well as targeting moiety. The developed nanoplatform has outstanding biocompatibility, well targeting ability, excellent near‐infrared radiation (NIR) photothermal conversion ability, controllable drug release with NIR irradiation response, and the capacity of delivering diverse drugs. The proposed nanoplatform is successfully used to specifically deliver chlorin e6 (Ce6) to CD‐44 over‐expressing cancer cells for PDT with a loading capacity of 0.605 mg mg−1 and controllable Ce6 release with NIR irradiation response. The combination of excellent NIR photothermal conversion ability and controllable Ce6 release confers the nanoplatform with enhanced singlet oxygen generation, which leads to more significant destruction of target cancer cells. The prepared photothermal heating‐responsive nanoplatform can enhance photodynamic therapeutic efficiency and hold great potential for multimodal cancer therapy.

Cetuximab tagged and oleic acid modified chitosan nanoparticles for tumor targeted quercetin delivery

Hypericin (HY) is a photoactive aromatic dianthraquinone that is considered a potent photodynamic agent. In this study, hypericin and two other photosensitizers, a hematoporphyrin derivative (Photogem®; PG) and a chlorin derivative (Photodithazine®; PZ), were compared in terms of their phototoxicity toward two cell lines, HEp-2 and Vero. The median inhibitory concentration (IC50) of each of the photosensitizers was obtained after a 16.2 J cm−2 dose of irradiation at 630 ± 10 nm. The IC50 values were 0.07 ± 0.01 (HY), 1.0 ± 0.2 (PZ), and 9 ± 1 μg mL−1 (PG) in HEp-2 cells and 0.3 ± 0.1 (HY), 1.6 ± 0.2 (PZ) and 11 ± 1 μg mL−1 (PG) in Vero cells, showing that HY is more phototoxic than the others when irradiated at 630 nm. If these results are analyzed, simultaneously, with the first-order constant for BSA tryptophan photooxidation, obtained by fluorescence decay (λexcitation = 280 nm), which are 11 × 10−3 min−1 ± 1. 10−3 min−1 (HY), 10 × 10−3 min−1 ± 1 × 10−3 min−1 (PZ), and 6 × 10−3 min−1 ± 1 × 10−3 min−1 (PG), it is possible to infer that the photodynamic efficiency alone is not sufficient to explain the higher HY phototoxicity. The lipophilicity is also an important factor for an efficient target cell accumulation and was assessed for all sensitizers through the octanol–water partition coefficient (log P): 1.20 ± 0.02 (HY), −0.62 ± 0.03 (PZ), and −0.9 ± 0.2 (PG). The higher value for HY correlates well with its observed superior efficiency to promote damage at low concentrations and doses. As HY is used for the long-term treatment of mild depression, it is considered safe for humans. This fact and the present results reinforce the great potential of this photosensitizer to replace porphyrin derivatives, with the advantages that mean it could be used as photosensitizer in clinical photodynamic therapy.

Photodynamic Therapy of Oligoethylene Glycol‐Dendronized Reduction‐Sensitive Porphyrins

Graphene oxide (GO) and its functionalized derivatives have attracted increasing attention in medical treatment. Herein, a reduction sensitive PEI‐GO‐SS‐TPP was synthesized for photodynamic therapy. More than 80% porphyrin release was observed in the presence of 10 mmol•L−1 DTT in one day. The confocal laser scanning microscopy confirmed that the cell uptake efficiency of PEI‐GO‐SS‐TPP was remarkably enhanced as compared to free porphyrin which was significantly dependent on incubation time. For photodynamic therapy, GSH‐OEt could effectively increase the photodynamic therapy efficiency of PEI‐GO‐SS‐TPP. Compared with free porphyrin, the toxicity from PEI‐GO‐SS‐TPP is much higher with a low IC50 (2.1 µg/mL) value. All results indicate that the PEI‐GO‐SS‐TPP PSs are promising for photodynamic therapy.