Silicon Phthalocyanine Research Articles

Fluorinated/non-fluorinated triphenylamine axially substituted silicon phthalocyanine: Synthesis and photophysical properties

Three novel fluorinated/ non-fluorinated triphenylamine axially substituted silicon phthalocyanines with AIE character were synthesized. They shows typical emission for phthalocyanine moieties at 678–688 nm as well as an emission at 396 nm for TPA moieties. • Three fluorinated/ non-fluorinated triphenylamine substituted silicon phthalocyanines with AIE character were synthesized and characterized. • Three molecules showed an typical emission for phthalocyanine moieties at 678–688 nm as well as an emission at 396 nm for TPA moieties. • Silicon phthalocyanines with fluorinated and triphenylamine substitutions possessed the highest fluorescence intensity, fluorescence quantum yield and singlet oxygen yield. • Silicon (IV) phthalocyanine with only triphenylamine (TPA) substitutions exhibited obviously AIE character in THF/water mixtures. Three novel fluorinated/non-fluorinated triphenylamine axially substituted silicon phthalocyanines (TPA-FBPA-SiPc, TPA-BPA-SiPc and TPA-SiPc) with aggreagtion-induced emission (AIE) character were synthesized by using silicon phthalocyanine (SiPc) as a core, triphenylamine (TPA) moieties as terminal groups, and fluorinate or non-fluorinate-bisphenol A as bridge groups. Such designed molecules showed typical emissions for SiPc at 675–688 nm as well as emissions for TPA moieties at 396 nm. Their photophysical and photochemical properties are affected by both the fluorinate-bisphenol A substitutions and TPA substitutions. TPA-FBPA-SiPc with both fluorinate-bisphenol A and TPA substitutions possessed the highest fluorescence intensity, fluorescence quantum yield as well as singlet oxygen yield. Besides, TPA-SiPc with only TPA substitutions could not only avoid the aggregation-caused quenching of phthalocyanines but also exhibite obvious AIE character in THF/water mixtures due to the presence of TPA moieties. This work could provide some useful structure and photophysical properties relationship for design novel phthalocyanine for photodynamic therapy.

Molecular and Supramolecular Approach to Highly Photocytotoxic Phthalocyanines with Dual Cell Uptake Pathways and Albumin-Enhanced Tumor Targeting.

Phototherapy for non-invasive cancer treatment has been extensively studied. An urgent challenge in phototherapy application is to fabricate appropriate targeted agents to achieve efficient therapeutic effect. Herein, a molecular and supramolecular approach for targeting phototherapy was reasonably designed and realized through the axial sulfonate modification of silicon(IV) phthalocyanines (Pcs), followed by supramolecular interaction with albumin. This approach can not only improve the photoactivities (e.g., fluorescence emission and reactive oxygen species production) of the Pcs but also enhance their tumor targeting. Most importantly, one of the deigned Pcs (4) can target HepG2 cells through dual cell pathways, leading to an extremely high phototoxicity with an EC50 (i.e., concentration of Pcs to kill 50% of cells under light irradiation) value of 2.0 nM. This finding presents a feasible strategy to realize efficient targeting phototherapy.

Novel Functional Axially Substituted Silicon (IV) Phthalocyanine Derivative and its Photochemical Properties

Photodynamic therapy is a highly specific and clinically approved method in which a non-toxic photosensitizer drug is administered to the patient for cancer treatment. Phthalocyanines with their long wavelength absorption and fluorescence from 650 to 800 nm can be used as photosensitizers for photodynamic therapy and are used in clinical trials. In this study, functional novel axially substituted silicon (IV) phthalocyanine (PS-2) was synthesized. Unsubstituted dichlorosilicon (IV) phthalocyanine was synthesized from 1,3-diiminoisoindoline via cyclotetramerization. The axial substitution reaction was carried out using dichlorosilicon (IV) phthalocyanine and excess of N-Boc-ethanolamine. Structural characterization of this novel PS-2 by FT-IR, mass, 1H NMR and UV-Vis spectroscopy were performed. Photochemical properties (photo degradation quantum yields (d) and singlet oxygen quantum yield () of PS-2, which are the first steps for cancer treatment, were investigated.

Correlating Morphology, Molecular Orientation, and Transistor Performance of Bis(pentafluorophenoxy)silicon Phthalocyanine Using Scanning Transmission X-ray Microscopy

Correlating Morphology, Molecular Orientation, and Transistor Performance of Bis(pentafluorophenoxy)silicon Phthalocyanine Using Scanning Transmission X-ray Microscopy

Influence of photosensitizer concentration and polymer composition on photoinduced antimicrobial activity of PVA- and PVA-chitosan-based electrospun nanomaterials cross-linked with tailor-made silicon(IV) phthalocyanine

The ongoing effort to eradicate pathogenic bacteria and viruses is a major endeavor that requires development of new and innovative materials. Materials based on photodynamic action represent an emerging and attractive area of research, and therefore, a broad understanding of chemical design principles is required. In the present study, we investigated the antibacterial and antiviral activities of five different nanofibrous membranes composed of poly(vinyl alcohol) or poly(vinyl alcohol)-chitosan mixture cross-linked through silicon(IV)phthalocyanine derivative with the aim to identify the role of the carrier polymer and photosensitizers concentration on its efficacy. A straightforward cross-linking process was adopted to create a water-stable material with an almost uniform distribution of the fiber structure, as revealed by scanning electron microscopy. The results of the antimicrobial studies showed that the increase in the amount of chitosan in the polymer mixture, rather than the increase in the photosensitizer concentration, enhanced the activity of the material. Due to their visible light-triggered antimicrobial activity, the resulting materials provide valuable opportunities for both topical antimicrobial photodynamic therapy and the area of environmental remediation.Graphical abstract

Cationic Axial Ligand Effects on Sulfur-Substituted Subphthalocyanines.

Herein, we report the synthesis of sulfur-substituted boron(III) subphthalocyanines (SubPcs) with cationic axial ligands. Subphthalocyanines were synthesized by a condensation reaction using the corresponding phthalonitriles and boron trichloride as a template. An aminoalkyl group was introduced on the central boron atom; this process was followed by N-methylation to introduce a cationic axial ligand. The peripheral sulfur groups shifted the Q band of SubPcs to a longer wavelength. The cationic axial ligands increased the polarity and enhanced the hydrophilicity of SubPcs. The effect of axial ligands on absorption and fluorescence properties is generally small. However, a further red shift was observed by introducing cationic axial ligands into the sulfur-substituted SubPcs. This change is similar to that in sulfur-substituted silicon(IV) phthalocyanines. The unique effect of the cationic axial ligand was extensively investigated by theoretical calculations and electrochemistry. In particular, the precise oxidation potential was determined using ionization potential measurements. Thus, the results of the present study provide a novel strategy for developing functional dyes and pigments based on SubPcs.

Persistent Luminescence-Based Theranostics for Real-Time Monitoring and Simultaneously Launching Photodynamic Therapy of Bacterial Infections.

External light irradiation is usually required in bacterial infection theranostics; however, it is always accompanied by limited light penetration, imaging interference, and incomplete bacterial destruction. Herein, a feasible "image-launching therapy" strategy is developed to integrate real-time optical imaging and simultaneous photodynamic therapy (PDT) of bacterial infections into persistent luminescence (PL) nanoparticles (NPs). Mesoporous silica NPs are used as a substrate for in situ deposition of PL nanodots of ZnGa2 O4 :Cr3+ to obtain mPL NPs, followed by surface grafting with silicon phthalocyanine (Si-Pc) and electrostatic assembly of cyanine 7 (Cy7) to fabricate mPL@Pc-Cy NPs. The PL emission of light-activated mPL@Pc-Cy NPs is quenched by Cy7 assembly at physiological conditions through the fluorescence resonance energy transfer effect, but is rapidly restored after disassembly of Cy7 in response to bacterial infections. The self-illuminating capabilities of NPs avoid tissue autofluorescence under external light irradiation and achieve real-time colorimetric imaging of bacterial infections. In addition, the afterglow of mPL NPs can persistently excite Si-Pc photosensitizers to promote PDT efficacy for bacterial elimination and accelerate wound full recovery with normal histologic features. Thus, this study expands the theranostic strategy for precise imaging and simultaneous non-antibiotic treatment of bacterial infections without causing side effects to normal tissues.

Synthesis and Sensor Properties of Silicon Phthalocyanine Axially Substituted with Bis-(Prop-2-Ynyloxy) Groups and Polymeric Phthalocyanines Bearing PEG Substituent by “Click” Chemistry

Synthesis and characterization of new axially substituted phthalocyanine complexes were done. Bis - (prop-2-ynyloxy) phthalocyaninato silicon (IV) compound was obtained from the reaction of 2-propin-1-ol with SiPcCl2. Polymeric phthalocyanine containing axially substituted PEG was obtained from the reaction of bis - (prop-2-ynyloxy) phthalocyaninato silicon (IV) compound and polyethylene glycol azido. The structure of the compounds was justified by FT-IR, 1H NMR, 13C NMR, UV–Vis, and mass spectra. The photophysical and photochemical properties of the phthalocyanine compound axially substituted with bis-(prop-2-ynyloxy) was investigated. Properties of the compounds were examined in terms of fluorescence quantum efficiency and singlet oxygen generating capacity, and the potential photosensitizer capacity of the compound was determined. In addition, polyethylene glycol group was added to the phthalocyanine compound by click reaction. The polymer product was obtained in blue color. Phthalocyanine(Pc) containing PEG polymeric units is soluble in dimethyl sulfoxide (DMSO). Absorption measurements of the compound at different concentrations were made. Both polyethylene glycol (PEG) and phthalocyanine compounds can be used in the manufacture of medical supplies due to their non-toxicity. UV–visible study of Bis-(prop-2-ynyloxy) phthalocyaninato silicon (IV) compound revealed its high selectivity for Fe3+ ion recognition.

Axially disubstituted silicon (IV) phthalocyanines containing different isoxazolyl groups: Design, syntheses, binding and in vitro phototoxic activities against SH-SY5Y cells

The axially different isoxazolyl disubstituted silicon (IV) phthalocyanines were synthesized by reaction of SiPcCl2 with 2-(5-isoxazolyl)-4-methylphenol or 4-chloro-2-(5-isoxazolyl)-5-methylphenol or 4-bromo-2-(5-isoxazolyl)phenol in the presence of NaH in toluene. Techniques used to illuminate the structure of silicon phthalocyanines included FT-IR, MALDI TOF, UV-vis, NMR spectroscopy. Then, we investigated DNA binding (ethidium bromide (EB)-competition studied by flow injection analysis) and in vitro cytotoxic/phototoxic actions on SH-SY5Y cells. The calculated Stern-Volmer constants were 3.7 × 103 M−1 (ISOX-M-SiPc), 1.3 × 105 M−1 (ISOX-Cl-SiPc), and 8.6 × 104 M−1 (ISOX-Br-SiPc), showing the stronger interaction of ISOX-Cl-SiPc with DNA than ISOX-M-SiPc and ISOX-Br-SiPc. The quenching constants (kq) values were calculated to be 1.61 × 1011M−1 s−1, 5.65 × 1012 M−1 s−1, and 3.74 × 1012 M−1 s−1 for ISOX-M-SiPc, ISOX-Cl-SiPc, and ISOX-Br-SiPc, respectively, which are larger than the maximum scatter collision quenching constant (2.0 × 1010 M−1 s−1). The results of MTT assay indicated that cell viabilities were 35 ± 7% and 10 ± 3% with light irradiation in the presence of ISOX-M-SiPc (at 30 and 100 µM). The results showed that ISOX-M-SiPc had the highest phototoxicity among the tested compounds but it had lower phototoxic effecs than methylene blue as a standard compound.

Non‐aggregated and water soluble axially disubstituted silicon phthalocyanines: Synthesis and inhibitory effect on acetylcholinesterase enzyme

AbstractIn this study, axially pyridine groups substituted silicon (IV) phthalocyanines (3PY‐7‐Si and 3PY‐8‐Si) and their water soluble derivatives 3PY‐7a‐SiQ and 3PY‐8a‐SiQ were synthesized and acetylcholinesterase inhibition properties were examined. Axially pyridine groups substituted silicon (IV) phthalocyanines (3PY‐7‐Si and 3PY‐8‐Si) and their water soluble derivatives 3PY‐7a‐SiQ and 3PY‐8a‐SiQ showed the various degrees of acetylcholinesterase inhibition activity. Their IC50 values causing 50% inhibition of the enzyme were ranged between 0.598 ± 0.068 and 0.886 ± 0.016 mM which 3PY‐7a‐SiQ was the best. These results demonstrated that the compounds might be effective agents against Alzheimer's disease.

Asymmetric, amphiphilic RGD conjugated phthalocyanine for targeted photodynamic therapy of triple negative breast cancer

Targeted photodynamic therapy (TPDT) is considered superior to conventional photodynamic therapy due to the enhanced uptake of photosensitizers by tumor cells. In this paper, an amphiphilic and asymmetric cyclo-Arg-Gly-Asp-d-Tyr-Lys(cRGDyK)-conjugated silicon phthalocyanine (RSP) was synthesized by covalently attaching the tripeptide Arg-Gly-Asp (RGD) to silicone phthalocyanine in the axial direction for TPDT of triple-negative breast cancer (TNBC). RSP was characterized by spectroscopy as a monomer in physiological buffer. Meanwhile, the modification of RSP with RGD led to a high accumulation of the photosensitizer in TNBC cells overexpressing ανβ3 integrin receptors which can bind RGD, greatly reducing the risk of phototoxicity. In vitro photodynamic experiments showed that the IC50 of RSP was 295.96 nM in the 4T1 cell line, which caused significant apoptosis of the tumor cells. The tumor inhibition rate of RSP on the orthotopic murine TNBC achieved 74%, while the untargeted photosensitizer exhibited no obvious tumor inhibition. Overall, such novel targeted silicon phthalocyanine has good potential for clinical translation due to its simple synthesis route, strong targeting, and high therapeutic efficacy for TPDT treatment of TNBC.

Layer-by-Layer Organic Photovoltaic Solar Cells Using a Solution-Processed Silicon Phthalocyanine Non-Fullerene Acceptor.

Silicon phthalocyanines (SiPcs) are promising, inexpensive, and easy to synthesize non-fullerene acceptor (NFA) candidates for all-solution sequentially processed layer-by-layer (LbL) organic photovoltaic (OPV) devices. Here, we report the use of bis(tri-n-butylsilyl oxide) SiPc ((3BS)2-SiPc) paired with poly(3-hexylthiophene) (P3HT) and poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))] (PBDB-T) donors in an LbL OPV structure. Using a direct architecture, P3HT/(3BS)2-SiPc LbL devices show power conversion efficiencies (PCEs) up to 3.0%, which is comparable or better than the corresponding bulk heterojunction (BHJ) devices with either (3BS)2-SiPc or PC61BM. PBDB-T/(3BS)2-SiPc LbL devices resulted in PCEs up to 3.3%, with an impressive open-circuit voltage (Voc) as high as 1.06 V, which is among the highest Voc obtained employing the LbL approach. We also compared devices incorporating vanadium oxide (VOx) or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a hole transporting layer and found that VOx modified the donor layer morphology and led to improved Voc. Probing the composition as a function of film layer depths revealed a similar distribution of active material for both BHJ and LbL structures when using (3BS)2-SiPc as an NFA. These findings suggest that (3BS)2-SiPc is a promising NFA that can be processed using the LbL technique, an inherently easier fabrication methodology for large-area production of OPVs.

Polyelectrolyte wrapped methylation morpholine-phthalocyanine@gold nanorod for synergistic photodynamic therapy and photothermal therapy photodegradation of DNA

It has been demonstrated that the synergistic photodynamic therapy and photothermal therapy offer a great therapeutic potential, although more research need to be exploit before this approach could be implemented. We investigated the synergistic effect of water soluble morpholine methylated phthalocyanine loaded on the surface of multilayer polyelectrolyte-coated gold nanorods for photodegradation of DNA. Two morpholine substituted zinc(II)/silicon(IV) phthalocyanines and their corresponding methylation water soluble cationic complexes were synthesized. The photophysical properties of two phthalocyanines were compared by UV/Vis, fluorescence spectroscopy and cyclic voltammetry methods. Tetra-[N-(methyliodide-morpholinyl)ethoxy] zinc(II) phthalocyanine (MLZnPcI4) was loaded into the multilayer polyelectrolyte-coated gold nanorods to form AuNR-PSS-MLZnPcI4 nanoparticles through electrostatic interaction. The nanoparticle was characterized by transmission electron microscope (TEM), atomic force microscope (AFM) as well as electronic differential system (EDS). The photophysical/photochemical properties of nanoparticles were studied. After being loaded on the gold nanorods, the fluorescence intensity, fluorescence quantum yield of MLZnPcI4 decreased. Upon irradiated by laser, MLZnPcI4 was released from nanoparticles due to the gold nanorods absorbed light energy and transformed it into heat and simultaneously produce 1O2, AuNR-PSS-MLZnPcI4 could effectively photodegrade DNA through synergistic photodynamic and photothermal therapy effect.

A Nanostructured Phthalocyanine/Albumin Supramolecular Assembly for Fluorescence Turn-On Imaging and Photodynamic Immunotherapy.

Smart phototheranostic nanomaterials are of significant interest for high-quality imaging and targeted therapy in the precision medicine field. Herein, a nanoscale photosensitizer (NanoPcM) is constructed through the self-assembly of morpholine-substituted silicon phthalocyanine (PcM) and albumin. NanoPcM displays a turn-on fluorescence depending on the acid-induced abolition of the photoinduced electron transfer effect (change in molecular structure) and disassembly of the nanostructure (change in supramolecular structure), which enables low-background and tumor-targeted fluorescence imaging. In addition, its efficient type I photoreaction endows NanoPcM with a superior immunogenic photodynamic therapy (PDT) effect against solid tumors. The combination of NanoPcM-based PDT and αPD-1-based immunotherapy can efficiently inhibit tumor growth, reduce spontaneous lung metastasis, and trigger abscopal effects. This study should provide a perspective for the future design of nanomaterials as promising phototheranostics for cancer imaging and therapy.

Novel piperazine-substituted silicon phthalocyanines exert anti-cancer effects against breast cancer cells

BackgroundPhotodynamic therapy (PDT) is one of the effective methods that can be used in cancer treatment. In this study, we aimed to investigate the PDT-mediated anti-cancer effects of newly synthesized piperazine-substituted silicon phthalocyanine molecules on breast cancer cells. MethodsThe compounds were analyzed by different spectroscopic techniques (FT-IR, UV–vis, 1H NMR, 13C NMR, MS) and the absorbance characteristics were determined. The cytotoxic effects of silicon phthalocyanines on MDA-MB-231 breast cancer cells and non-tumorigenic MCF-10A cells were evaluated using MTT assay. Detection of apoptotic populations was performed by Annexin V/7AAD assay. H2DCFDA dye was used to analyze intracellular reactive oxygen species. The clonogenic activity and cellular motility were analyzed by colony formation assay and in vitro scratch assay, respectively. Caspase-3, PARP1, and cleaved-PARP1 protein levels were analyzed by western blot studies. ResultsPiperazine-substituted silicon phthalocyanines caused high levels of cytotoxic effects and apoptotic cell population in MDA-MB-231 cells, while low levels of cytotoxic effects were observed in MCF-10A cells. Following PDT, intense ROS formation was detected in MDA-MB-231 cells. Colony-forming capacity and cellular motility of MDA-MB-231 cells were highly restricted following PDT, whereas these effects were observed at lower levels in MCF-10A cells. Silicon phthalocyanines caused different effects on cleaved-PARP1 expressions of MDA-MB-231 and MCF-10A cells. ConclusionThese results suggest that piperazine-substituted silicon phthalocyanines can exert selective anti-cancer effects on breast cancer cells and activate cellular death through different molecular pathways. Hence, we believe that they may be used as effective photosensitizer agents in the future.

Highlighting the processing versatility of a silicon phthalocyanine derivative for organic thin-film transistors

Silicon phthalocyanine (SiPc) derivatives have recently emerged as promising materials for n-type organic thin-film transistors (OTFTs) with the ability to be fabricated either by solid state or solution processes through axial functionalization.

Ligand release from silicon phthalocyanine dyes triggered by X-ray irradiation.

Ligand release from silicon phthalocyanine (SiPc) dyes triggered by near-infrared (NIR) light is a key photochemical reaction involving caged compounds based on SiPc. Although NIR light is relatively permeable compared with visible light, this light can be attenuated by tissue absorption and scattering; therefore, using light to induce photochemical reactions deep inside the body is difficult. Herein, because X-rays are highly permeable and can produce radicals through the radiolysis of water, we investigated whether the axial ligands of SiPcs can be cleaved using X-ray irradiation. SiPcs with different axial ligands (alkoxy, siloxy, oxycarbonyl, and phenoxy groups) were irradiated with X-rays under hypoxic conditions. We found that the axial ligands were cleaved via reactions with hydrated electrons (e-aq), not OH radicals, generated from water in response to X-ray irradiation, and SiPc with alkoxy groups exhibited the highest cleavage efficiency. A quantitative investigation revealed that X-ray-induced axial ligand cleavage proceeds via a radical chain reaction. The reaction is expected to be applicable to the molecular design of X-ray-activatable functional molecules in the future.

Anticancer activity of novel silicon phthalocyanines against the colorectal adenocarcinoma cell line (DLD-1)

This study presents the effect of the axial ligand length on the pharmacological features of new water-soluble axially disubstituted silicon phthalocyanines bearing 2,4,6-tris((dimethylamino)methyl)phenoxy groups.

Novel Silicon Phthalocyanines with Improved Singlet Oxygen Generation by Sono-Photochemical Applications

Novel Silicon Phthalocyanines with Improved Singlet Oxygen Generation by Sono-Photochemical Applications

Anticancer and biological properties of new axially disubstituted silicon phthalocyanines.

This study reports the synthesis of three novel axially disubstituted silicon phthalocyanines (1-3-Si) and their quaternized phthalocyanines (1-3-QSi). The resulting compounds were characterized by applying spectroscopic techniques including 1H NMR, FT-IR, UV-vis, and mass spectroscopy. The biological properties of compounds 1-3-QSi, including DNA cleavage activities, DNA binding modes, and topoisomerase enzyme inhibition activities, were investigated using agarose gel electrophoresis. pBR322 plasmid DNA, CT-DNA, and AL-DNA (isolated from apricot leaf) were used for DNA studies. All the quaternized compounds exhibited acceptable DNA cleavage activities. Human topoisomerase I and E. coli topoisomerase enzymes were used for the topoisomerase I inhibition studies. All the quaternized complexes inhibited topoisomerase I activity. Moreover, these compounds were screened for cytotoxic and apoptotic effects against a human colon cancer cell line (DLD-1) by performing MTT and Annexin V assays. They exhibited toxicity and apoptotic effect on the DLD-1 cell line. The findings reveal that the compounds can be utilized for cancer therapy after further investigations.