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A novel delivery system for the hydrophobic photosensitizer, hypocrellin A, has been developed that uses hypocrellin A nanoparticles prepared by a reprecipitation method. In comparison to the unmodified photosensitizer, the hypocrellin A nanoparticles not only possess superior water solubility, higher water and light stability but also display high singlet oxygen production and DNA photocleavage capability. [Copyright &y& Elsevier]

The surface binding association between a positively charged polymeric complex of hypocrellin A (HA) with La3+ (La3+-HA) and calf thymus DNA (CT DNA) was confirmed by ESR and laser flash photolysis techniques along with UV-Vis absorption and fluorescence emission spectra. This surface binding, in cooperation with the longer triplet excited state lifetime of La3+-HA, gave rise to a stronger photodamage of CT DNA both in aerobic and anaerobic conditions by La3+-HA compared with HA. [Copyright &y& Elsevier]

Highly stretchable electrodes with electrically robust behavior are critical for wide applications of soft robots, electronic skins, and flexible sensors. However, it remains challenging to fabricate such electrodes with traditional fabrication methods, such as lithography, conductive composite material synthetization, stencil printing, and microchannel injection. Herein, a facile method is proposed to construct robust and stretchable electrodes by direct‐written liquid metal (LM) onto a predeposited interface bonding layer, which greatly improves the interfacial force between the LM and substrate. An electrospun graphene oxide/thermoplastic polyurethane composite nanofiber membrane is used as the bonding layer, which provides rich –OH on the interface and in situ forming of hydrogen bond (H‐bond) with the LM oxide layer. A prototype electrode shows stretchability of 580%. The resistance remains stable that varies from 2.8 to 19.3 Ω at 500% elongation, and varies slightly after 7500 stretching cycles under 50% elongation, from 2.6–4.0 to 4.4–6.4 Ω. The fabrication technique is demonstrated with applications in stretchable circuit board assemblies and stretchable electronic cables, indicating a potential effective method for fabricating high‐performance stretchable electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designed and verify a novel PDT system based on BRET. • Prepared nanoparticles loaded- firefly D-luciferin (FLuc-CPNPs) and nanoparticles loaded-hypericin (Hyp-CPNPs • The nanoparticles promoted self-illuminated photodynamic cytotoxicity comparable effect to traditional PDT system. • The nanoparticles could locate on the mitochondrial and had higher ROS generation. The purpose of this study was to investigate the self-sensitization of photosensitizer without an external light source to produce a photodynamic therapy (PDT) effect based on the principle of bioluminescence resonance energy transfer (PDT-BRET). First, we demonstrated that HeLa cells could efficiently express firefly luciferase (FLase) after the firefly luciferase gene was transfected with the FLase-gene plasmid (FLase-GP), and proved that FLase could act on the substrate firefly D-luciferin (FLuc) to produce photons. The generated photons activate the photosensitizer hypericin (Hyp) and induce cytotoxicity. Then, we successfully prepared carboxymethyl chitosan-modified poly(lactic-co-glycolic acid) nanoparticles (CPNPs) loaded with FLuc (FLuc-CPNPs) and with loaded Hyp (Hyp-CPNPs). Their physicochemical and pharmaceutical characteristics indicated that they were an excellent drug delivery system. Characterization of the biological effects showed that they could be located in the mitochondrial, had higher ROS generation and stronger cytotoxicity. In vivo results also showed that PDT-BRET was as effective as classic PDT. PDT-BRET and the related drug delivery system are expected to become a new platform for anticancer therapy. [ABSTRACT FROM AUTHOR]

Abstract: The interactions between Lysozyme and Hypocrellin A are investigated in details using time-resolved fluorescence, fourier transform infrared spectroscopy (FTIR), circular dichroism spectroscopy (CD), three-dimensional fluorescence spectra, and thermal gravimetric analysis (TGA) techniques. The results of time-resolved fluorescence suggest that the quenching mechanism is static quenching. FTIR and CD spectroscopy provide evidences of the reducing of α-helix after interaction. Hypocrellin A could change the micro-environmental of Lysozyme according to hydrophobic interaction between the aromatic ring and the hydrophobic amino acid residues, and the altered polypeptide backbone structures induce the reduction of α-helical structures. Moreover, TGA study further demonstrates the structure changes of Lysozyme on the effect of Hypocrellin A. This study could provide some important information for the derivatives of HA in pharmacy, pharmacology and biochemistry. [Copyright &y& Elsevier]

Abstract: A new dual fluorescent probe was prepared by encapsulating the complex of cerium (III) and quinizarin into silica nanoparticles. Cerium (III) and quinizarin can form a stable dual fluorescent complex in ethanol, but this complex would dissociate in the aqueous medium, which limited its application in biosystem. So, such complex was encapsulated inside the silica nanoparticles to solve this problem. The results indicated that the stability and water solubility of the complex were greatly improved after been encapsulated into the silica nanoparticles. In addition, its dual fluorescent probe function was studied in vitro. [Copyright &y& Elsevier]

The interaction of Elsinochrome A (EA) with calf thymus DNA (CT-DNA) has been investigated by UV-vis spectra and fluorescence spectra. The results show that EA can bind with CT-DNA and binding sites are destroyed after irradiation by visible light, which indicates that EA is a promising candidate for photodynamic therapy. In addition, the binding mechanism is studied using fluorescence quenching test and ethidium bromide (EB) replace assay experiments. The results suggest that EA and CT-DNA are binding with a strong force and the major binding mode of EA with DNA could be the electrostatic binding. [ABSTRACT FROM AUTHOR]

Tetra-tert-butyl zinc(II) phthalocyanine has attracted great attention as an effective photosensitizer in the field of photodynamic therapy. However, tetra-tert-butyl zinc(II) phthalocyanine is hydrophobic and trends to aggregate to form the inactive congeries in aqueous solution, which dramatically reduce its photodynamic activity. To solve this problem, tetra-tert-butyl zinc(II) phthalocyanine was encapsulated into silica nanoparticles using microemulsion method and its properties were studied using spectroscopic methods. After embedded inside the silica nanoparticles, the water-solubility, stability and monomer percent of phthalocyanine in water were greatly improved comparing with the free phthalocyanines, and therefore, its photo-induced singlet oxygen generation efficacy of drug-doped silica nanoparticles was improved. The results indicated that encapsulation hydrophobic phthalocyanine into silica nanoparticles was an effective way to solve their problems and promote their clinical application. [ABSTRACT FROM AUTHOR]

Abstract: We report a facile silica nanovehicle preparation procedure for hydrophobic drug delivery, which is carried out in water without adding any surfactant and additional catalyst. This strategy includes hydrophobic drug nanopaticle preparation by reprecipitation method and in situ hydrolyzation and polymerization to encapsulate this naoparticle using only N-(β-amimoethyl)-γ-aminopropyltyiethoxysilane (AETPS). To demonstrate this technique hypocrellin A (HA), a hydrophobic photosensitizing anticancer drug, is embedded into silica nanovehicle using this simple method. The resulting HA encapsulated nanovehicles (HANV) are monodisperse and stable in aqueous solution. Comparative studies with free HA and entrapped HA have demonstrated that the encapsulation effect on the embedded photosensitizer nanoparticle significantly enhances the efficacy of singlet oxygen generation and, thereby, the in vitro photodynamic efficacy. [Copyright &y& Elsevier]

Abstract: Iridoid glycosides, harprocumbide A (6″-O-α-d-galactopyranosylharpagoside, 1) and harprocumbide B (6″-O-(cis-p-coumaroyl)-procumbide, 2) were isolated from the tubers of Harpagophytum prucumbens D.C., along with nine known iridoid glycosides 6-O-α-d-galactopyranosylharpagoside (3), and harpagoside (4), harpagide (5), 8-cinnamoylmyoporoside (6), 8-O-feruloylhapagide (7), procumbide (8), 6″-O-(p-coumaroyl)-procumbide (9), 8-O-(p-coumaroyl)-harpagide (10) and 8-O-(cis-p-coumaroyl)-harpagide (11). Compound 10 showed marginal inhibition activity against macrophages respiratory burst. [Copyright &y& Elsevier]

Abstract: Photodynamic therapy (PDT) has been proved to be highly effective in the treatment of different types of cancer. A novel nano-colloid based drug carrier for PDT of elsinochrome A (EA), a hydrophobic photosensitizer, was prepared using single 3-aminopropyltriethoxysilane (APTES) which is traditionally only used as surface modification reagent. The resulting nano-colloid immobilized photosensitizers provide good water solubility and photostability. In addition, EANC preserve the key step of photogeneration of singlet oxygen, necessary for photodynamic action. Moreover, significant damage to calf thymus DNA was observed upon irradiation with light. Thus, the potential of using nano-colloid as drug carriers for photodynamic therapy has been demonstrated. [Copyright &y& Elsevier]