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Low Intensity Light-Induced Paclitaxel Release from Lipid Based Nano-delivery Systems
摘要： Light-induced drug release has been explored as a strategy for externally modulating the release of drug from delivery systems. This study reports the development of a solid lipid nanoparticulate system (SLN) for paclitaxel (PTX), where photosensitizer-mediated oxidation of lipids was used as a mechanism for controlling the drug release. Low-intensity (23 mW/cm2) near-infrared (around 730 nm) illumination was externally applied as the light source. Paclitaxel release was less than 10% within 4 hrs from these SLN and was 8-fold higher after application of light at time zero. The other advantages of this approach include the use of ascorbic acid as an antioxidant for enhancing the release and storage stability of the delivery system. Antioxidant like ascorbic acid in the SLN decrease the degradation of lipid by 8-fold within 4 months of storage. Presence of ascorbic acid and light illumination of SLN containing PTX further decreased the IC50 by 2 times in A549 cells. The uniqueness of this approach allows the possibility of external modulation to achieve pulsatile release from the delivery system. The light used in the NIR spectral range of 700-850 nm, which has the greatest tissue penetration ability, with a low intensity will be safe for normal tissues.
关键词： near-infrared photosensitizer,anticancer,lipid nanoparticles,hydrophobic drugs,controlled release,low-intensity light
更新于2025-09-19 17:15:36
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Salicylic Acid as a Photosensitizer for Thymidine Dimerization Induced by UV
摘要： When a neutral solution of a nucleoside mixture was irradiated with UV light having wavelength longer than 300 nm, addition of salicylic acid to the solution greatly accelerated the reaction of thymidine. The UV light irradiation of thymidine solution in the presence of salicylic acid resulted in four major product peaks in HPLC. All the products were identified as isomers of cyclobutane thymidine dimers by MS and NMR. The cyclobutane thymidine dimers were generated from thymidine almost exclusively. UV irradiation with the longer wavelength of 350 nm induced almost no reaction. The results indicate that salicylic acid is a photosensitizer for thymidine dimerization excited by UV light of wavelength 300 to 350 nm.
关键词： photosensitizer,UV light,salicylic acid,thymidine dimer
更新于2025-09-19 17:15:36
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Investigation of copper-cysteamine nanoparticles as a new photosensitizer for anti-hepatocellular carcinoma
摘要： Hepatocellular carcinoma (HCC) is a primary malignancy of the liver and occurs predominantly in patients with underlying chronic liver disease and cirrhosis. HCC is now the third leading cause of cancer deaths worldwide, with over 500,000 people affected. However, there is no complete effective (ideal) treatment for liver cancer yet, and the new methods are expected to be discovered. Herein, for the first time, we report the anti-HCC effects of copper-cysteamine nanoparticles (Cu-Cy NPs), a new type of photosensitizers. An in vitro 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay shows that Cu-Cy NPs could significantly reduce the activity of HepG2 cells at a very low dose after a short time of ultraviolet radiation. In addition, we found that cell death was induced by Cu-Cy NPs, which is associated with cellular apoptosis. This implied that apoptosis might be the main mechanism of the Cu-Cy’s anti-HCC activity. Furthermore, we found that Cu-Cy NPs obviously inhibited the tumor growth in vivo. More interestingly, we found that the soluble Cu-Cy NPs were able to enter exosomes which were secreted by tumor cells, and exosomes could be used to deliver Cu-Cy NPs to target tumor cells. All these observations suggest that Cu-Cy NPs have a good potential for cancer treatment.
关键词： copper-cysteamine,Hepatocellular carcinoma,nanoparticles,photosensitizer,photodynamic therapy
更新于2025-09-19 17:15:36
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The apoptosis pathway of photodynamic therapy using 9-HpbD-a in?AMC-HN3 human head and?neck cancer cell line and?in vivo
摘要： 9-Hydroxypheophorbide-a (9-HpbD-a), a new photosensitizer was extracted from the green alga Spirulina platensis. The anticancer effects of photodynamic therapy (PDT) treatment using 9-HpbD-a against human head and neck cancer cell HN3 and in vivo mice model were investigated. Cells were incubated with 9-HpbD-a for at least 6 hours or more followed by the laser irradiation. Cytotoxicity of 9-HpbD-a against HN3 cell was determined using the MTT assay, propidium iodide and Hoechst 33342 staining and transmission electron microscopy (TEM). To determine the mechanism of cell death, Western blot analysis was performed. The antitumor effect was confirmed in a cancer cell xenograft nude mouse model by photodynamic therapy (PDT) using 9-HpbD-a. For normal control and the 9-HpbD-a only treated group, tumor tissues showed continuous tumor growth (100%). For laser only treated experimental group, 3 treatments showed no remission (75.0%), and was one recurrence (25.0%). Out of 16 tumors in the fourth group of photodynamic treatment, 10 cured (62.5%), 4 recurrence (25.0%), and 2 did not heal (12.5%) were confirmed. PDT using a 9-HpbD-a and 665 nm diode laser showed significant antitumor effects. Thus PDT using 9-HpbD-a can be a useful new treatment method in the treatment of cancer in the future.
关键词： Photosensitizer,Photodynamic therapy,9-Hydroxypheophorbide-a,Apoptosis,Cell death mechanism
更新于2025-09-19 17:15:36
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Prickly pear fruit extract as photosensitizer for dye-sensitized solar cell
摘要： In this study, we have explored prickly pear fruit extract as a photosensitizer in dye-sensitized solar cells (DSSC). The photosensitizer was isolated from prickly pear fruits by extraction method using ethanol as solvent. Structural, morphological and optical properties of prickly pear extract characterized by XRD, SEM, UV-VIS-DRS, FTIR spectra, respectively. UV-VIS absorption and FTIR spectra of prickly pear fruit extract confirm the presence of betacyanin and hydroxyl groups anchoring onto the TiO2 surface. The absorption maxima at 534 nm in the visible region is prominent. The presence of betacyanin in the extract is indicative that the dye will be useful as a sensitizer in DSSC. Reflectance edge of TiO2 is red-shifted upon the adsorption of natural dye. The XPS analysis showed the charge state of hydroxyl (O-H) groups that are attached with the natural dye adsorbed onto the surface of TiO2. The fabricated DSSC had a conversion efficiency (?) of 0.56 % with highest fill factor (FF) of 85.0%, open-circuit voltage (Voc) of 0.56 V and short circuit-current density (Jsc) with 1.17 mA/cm2. The value obtained for the fill factor is promising to further explore the prickly pear extract for applicability in DSSC by improving the efficiency.
关键词： Dye-sensitized solar cells,Hydroxyl groups,Prickly pear fruit extract,Photosensitizer,TiO2,Fill factor,Betacyanin,Conversion efficiency
更新于2025-09-19 17:13:59
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-carboline alkaloids in Dye sensitized solar cell. Electrochemical and spectroscopic characterization
摘要： Dye-sensitized solar cell (DSSC) technology represents a valuable source for renewable energy production. Although with a rather low conversion efficiency, the continuous improvement of the price/performance ratio is making this technology more competitive than other sources of electrical power generation. To date, one of the major challenges is the search of novel and low-cost photosensitizers, a key player in the overall photo-conversion process. Natural dyes have shown to be an excellent alternative that still needs to be further explored. In this work, the spectroscopic and electrochemical properties of two different families of naturally occurring pigments (i.e, β-carboline alkaloids (βCs) and the red protein R-phycoerythrin (R-PE)) as well as their role in DSSCs are addressed. DSSC assemblies show that R-PE represents a highly suitable photosensitizer showing quite a high stability with a relative high solar energy to electricity conversion efficiency (η = 0.11 %) when comparing with other recombinant proteins (η = 0.30 %). Algae extracts used without further purification showed herein the highest efficiencies. The latter fact has a concomitant positive effect on the overall production cost of these photovoltaic cells. Surprisingly, and despite their positive effect on the coating of the semiconductor surface, the use of βCs as additive decreases the overall conversion efficiency of the R-PE based DSSCs evaluated. Data support the hypothesis these alkaloids would be blocking the incident UVB/UVA radiation.
关键词： β-carboline alkaloids,Photosensitizer,R-phycoerythrin,Renewable energy,Dye-sensitized solar cell
更新于2025-09-16 10:30:52
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Effective Preparation of Nanoscale CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> Perovskite Photosensitizers for Mesoporous TiO <sub/>2</sub> ‐Based Solar Cells by Successive Precursor Layer Adsorption and Reaction (SPLAR) Process
摘要： Nanoscale CH3NH3PbI3 perovskite sensitizers are grown step-by-step by delivering each precursor successively onto the surface of mesoporous (meso) TiO2 electrode. Using Pb(NO3)2 ions as a lead(II) source and CH3NH3I (MAI) for methylammonium and iodide sources, repetitive cycles of the two dipping steps are successful in growing few nanometer-sized MAPbI3 gradually on the TiO2 surface inside the meso-TiO2 film. However, some aggregates are observed on the top-surface of meso-TiO2 film due to slight dissolution of PbI2 and its accumulation/reaction with MAI at the top-surface of meso-TiO2 film. To solve this inhomogeneity during the course of the deposition, a nondestructive multiple deposition route for nanoscale MAPbI3 is suggested as a successive precursor layer adsorption and reaction (SPLAR) process where, from the second cycle of deposition, PbI2 is delivered with the help of an ionic liquid compound dissolved in dichloromethane. With this new Pb-precursor in less-polar solvents by spin-coating process, nanoscale MAPbI3-sensitizers are grown step-by-step without dissolution of pre-formed perovskites back to PbI2 or formation of some aggregates at the top-surface. After the third cycle of SPLAR deposition, about 7.0 nm-size MAPbI3-sensitizers are prepared and they display enhanced photovoltaic performance (7.18± 0.31 %) compared to devices obtained from only one cycle (5.74± 0.30 %).
关键词： solid-state dye-sensitized solar cells,nanoscale perovskite,successive adsorption and reaction,photosensitizer
更新于2025-09-16 10:30:52
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Sharp pH-responsive mannose prodrug polypeptide nanoparticles encapsulating a photosensitizer for enhanced near infrared imaging-guided photodynamic therapy
摘要： Mannose has been reported as a novel drug to kill cancer cells. The prodrug of mannose will promote its targeted delivery and enrichment at the tumor site and cancer cells. Here, a pH-sensitive polypeptide copolymer with a tertiary amine group has been prepared and a mannose molecule was conjugated to the polymer through the formation of a Schiff base. At the same time, an iodinated boron dipyrromethene (BDPI) photosensitizer with high singlet oxygen generation efficacy and near infrared (NIR) fluorescence was encapsulated by the nanoparticles, which makes it a potential pH-sensitive NIR imaging-guided chemotherapy/PDT agent. In vitro and in vivo studies reveal that in a tumor acidic environment, the protonation of the tertiary amine group destroyed the nanostructure of the nanoparticles, resulting in increased BDPI release. Meanwhile, the bond cleavage of the Schiff base led to the release of conjugated mannose and synergistic inhibition of tumor cell growth with the PDT effect was realized. The combination of these two kinds of tumor suppression effects and photodynamic therapy made this pH-sensitive polypeptide delivery system show great potential for further cancer therapy.
关键词： polypeptide nanoparticles,mannose prodrug,pH-responsive,photodynamic therapy,photosensitizer,near infrared imaging
更新于2025-09-16 10:30:52
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Natural Dye of Musa acuminata bracts as Light Absorbing Sensitizer for Dye-Sensitized Solar Cell
摘要： Dye-Sensitized Solar Cell (DSSC) has attracted researcher attentions because of its ability in converting light and has good performance at relatively low costs. The highest conversion efficiency is 4%. Musa acuminata bracts extract and a spin coating method are used. DSSC is fabricated based on musa acuminata bracts extract in a variation of mass fraction 0.1–0.5 with an increase of 0.1. The absorbances of organic dyes are determined using Vis-Nir and the highest one is found at 0.3 mass fraction with a wavelength spectrum of 500-600 nm. Conversion efficiency is determined using the Nachriebe 101 tool.
关键词： natural dye,dye-sensitized solar cell,musa acuminata bracts,thin film,photosensitizer
更新于2025-09-16 10:30:52
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Performance of Natural Dyes in Dye-Sensitized Solar Cell as Photosensitizer
摘要： In this research work five types of titanium dioxide (TiO2) nanocrystalline sol–gel paste with three different types of dye have been prepared and layered on Indium Tin-Oxide coated glass to fabricate dye-sensitized solar cells. The dyes extracted from Malabar spinach seeds (MSS), Red spinach and Pomegranate burgs were used as photosensitizer. All the electrical properties investigated by LCR meter were found to be improved with MSS dye but sample with 0.3 M HNO3 (sample-3) exhibited the best electrical properties. The current–voltage characteristics for all the samples showed ideal behavior. The highest maximum power of 176.3 μW and efficiency of 9.23% was found for sample-3 with MSS dye. The smallest crystallite size was found to be 28.82 nm for sample-3 by XRD data which was also supported by the SEM results. Thus, this study reveals that MSS dye has the great potential to be used as photosensitizer.
关键词： TiO2,Solar cell,Dye-sensitized,Photosensitizer,Electrical properties
更新于2025-09-12 10:27:22