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Главная страница Новости науки Journal of Photochemistry and Photobiology B: Biology
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ScienceDirect Publication: Journal of Photochemistry and Photobiology B: Biology
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ScienceDirect Publication: Journal of Photochemistry and Photobiology B: Biology
  • Magnetic and photocatalytic studies on Zn1−xMgxFe2O4 nanocolloids synthesized by solvothermal reflux method
    Publication date: December 2017
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 177

    Author(s): A. Manohar, C. Krishnamoorthi

    Biocompatible magnetic semiconductor Zn1−xMgxFe2O4 (x=0, 0.1, 0.3, 0.5 & 0.7) nanoparticles of around 10nm diameter were synthesized by solvothermal reflux method. The method produces well separated and narrow size distributed nanoparticles. Crystal structure, morphology, particles surface properties, surfactant quantity, colloidal stability, magnetic properties and photocatalytic properties of the synthesized nanoparticles were studied. Different characterizations confirmed that all compounds were single crystals and superparamagnetic at room temperature. Saturation mass magnetization (M s =57.5emu/g) enhances with substituent Mg2+ concentration due to promotion of mixed spinel (normal and inverse) structure. Photocatalytic activity of all synthesized magnetic semiconductor nanoparticles were studied through methylene blue degradation. The degradation of 98% methylene blue was observed on 60 min irradiation of light. It is observed that photocatalytic activity slightly enhances with substituent Mg2+ concentration. The synthesized biocompatible magnetic semiconductor nanoparticles can be utilized as photocatalysts and could also be recycled and separated by applying an external magnetic field.

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  • Effect of different diode laser wavelengths on root dentin decontamination infected with Enterococcus faecalis
    Publication date: November 2017
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 176

    Author(s): Caroline Cristina Borges, Carlos Estrela, Fabiane Carneiro Lopes, Regina Guenka Palma-Dibb, Jesus Djalma Pecora, Cyntia Rodrigues De Araújo Estrela, Manoel Damião de Sousa-Neto

    The objective of this study was to evaluate the antibacterial effect and the ultrastructural alterations of diode laser with different wavelengths (808nm and 970nm) and its association with irrigating solutions (2.5% sodium hypochlorite and 2% chlorhexidine) in root dentin contaminated by a five days biofilm. Thirteen uniradicular teeth were sectioned into 100 dentin intraradicular blocks. Initially, the blocks were immersed for 5min in 17% EDTA and washed with distilled water for 5min, then samples were sterilized for 30min at 120°C. The dentin samples were inoculated with 0.1mL of E. faecalis suspension in 5mL BHI (Brain Heart Infusion) and incubated at 37°C for 5days. After contamination, the specimens were distributed into ten groups (n=10) according to surface treatment: GI - 5mL NaOCl 2.5%, GII - 5mL NaOCl 2.5%+808nm diode (0.1W for 20s), GIII - 5mL NaOCl 2.5%+970nm diode (0.5W for 4s), GIV - 808nm diode (0.1W for 20s), GV - 970nm diode (0.5W for 4s), GVI - CHX 2%, GVII - CHX 2%+808nm diode (0.1W for 20s), GVIII - CHX 2%+970nm diode (0.5W for 4s), GIX - positive control and GX - negative control. Bacterial growth was analyzed by turbidity and optical density of the growth medium by spectrophotometry (nm). Then, the specimens were processed for analysis ultrastructural changes of the dentin surface by SEM. The data was subject to the One-way ANOVA test. GI (77.5±12.1), GII (72.5±12.2), GIII (68.7±8.7), GV (68.3±8.7), GVI (62.0±5.5) and GVII (67.5±3.3) were statistically similar and statistically different from GIV (58.8±25.0), GVIII (59.2±4.0) and control groups (p<0.05). SEM analysis showed a modified amorphous organic matrix layer with melted intertubular dentin when dentin samples were irradiated with 970nm diode laser; erosion of the intertubular dentin in blocks submitted to 808nm diode laser irradiation; and an increased erosion of the intertubular dentin when 2.5% NaOCl was associated to the different wavelengths lasers. All the therapeutic protocols were able to reduce the bacterial contingent in dentin blocks, and the association of diode laser and solutions did not significantly improve the reduction of the bacterial contingent.







  • Disinfection and healing effects of 222-nm UVC light on methicillin-resistant Staphylococcus aureus infection in mouse wounds
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Kouji Narita, Krisana Asano, Yukihiro Morimoto, Tatsushi Igarashi, Michael R. Hamblin, Tianhong Dai, Akio Nakane

    UVC radiation is known to be highly germicidal. However, exposure to 254-nm-UVC light causes DNA lesions such as cyclobutane pyrimidine dimers (CPD) in human cells, and can induce skin cancer after long-term repeated exposures. It has been reported that short wavelength UVC is absorbed by proteins in the membrane and cytosol, and fails to reach the nucleus of human cells. Hence, irradiation with 222-nm UVC might be an optimum combination of effective disinfection and biological safety to human cells. In this study, the biological effectiveness of 222-nm UVC was investigated using a mouse model of a skin wound infected with methicillin-resistant Staphylococcus aureus (MRSA). Irradiation with 222-nm UVC significantly reduced bacterial numbers on the skin surface compared with non-irradiated skin. Bacterial counts in wounds evaluated on days 3, 5, 8 and 12 after irradiation demonstrated that the bactericidal effect of 222-nm UVC was equal to or more effective than 254-nm UVC. Histological analysis revealed that migration of keratinocytes which is essential for the wound healing process was impaired in wounds irradiated with 254-nm UVC, but was unaffected in 222-nm UVC irradiated wounds. No CPD-expressing cells were detected in either epidermis or dermis of wounds irradiated with 222-nm UVC, whereas CPD-expressing cells were found in both epidermis and dermis irradiation with 254-nm UVC. These results suggest that 222-nm UVC light may be a safe and effective way to reduce the rate of surgical site and other wound infections.







  • Determination of membrane disruption and genomic DNA binding of cinnamaldehyde to Escherichia coli by use of microbiological and spectroscopic techniques
    Publication date: Available online 10 November 2017
    Source:Journal of Photochemistry and Photobiology B: Biology

    Author(s): Tian-Fu He, Zhi-Hong Zhang, Xin-An Zeng, Lang-Hong Wang, Charles S. Brennan

    This work was aimed to investigate the antibacterial action of cinnamaldehyde (CIN) against Escherichia coli ATCC 8735 (E. coli) based on membrane fatty acid composition analysis, alterations of permeability and cell morphology as well as interaction with genomic DNA. Analysis of membrane fatty acids using gas chromatography–mass spectrometry (GC–MS) revealed that the proportion of unsaturated fatty acids (UFA) and saturated fatty acids (SFA) were the major fatty acids in plasmic membrane, and their levels were significantly changed after exposure of E. coli to CIN at low concentrations. For example, the proportion of UFA decreased from 39.97% to 20.98%, while the relative content of SFA increased from 50.14% to 67.80% as E. coli was grown in increasing concentrations of CIN (from 0 to 0.88mM). Scanning electron microscopy (SEM) showed that the morphology of E. coli cells to be wrinkled, distorted and even lysed after exposure to CIN, which therefore decreased the cell viability. The binding of CIN to genomic DNA was probed using fluorescence, UV–Visible absorption spectra, circular dichroism, molecular modeling and atomic force microscopy (AFM). Results indicated that CIN likely bound to the minor groove of genomic DNA, and changed the secondary structure and morphology of this biomacromolecule. Therefore, CIN can be deem as a kind of natural antimicrobial agents, which influence both cell membrane and genomic DNA.







  • Mesoporous silica for drug delivery: Interactions with model fluorescent lipid vesicles and live cells
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Munmun Bardhan, Anupa Majumdar, Sayantan Jana, Tapas Ghosh, Uttam Pal, Snehasikta Swarnakar, Dulal Senapati

    Formulated mesoporous silica nanoparticle (MSN) systems offer the best possible drug delivery system through the release of drug molecules from the accessible pores. In the present investigation, steady state and time resolved fluorescence techniques along with the fluorescence imaging were applied to investigate the interactions of dye loaded MSN with fluorescent unilamellar vesicles and live cells. Here 1,2-dimyristoyl-sn-glycero-3-phospocholine (DMPC) was used to prepare Small Unilamellar Vesicles (SUVs) as the model membrane with fluorescent 1,6-diphenyl-1,3,5-hexatriene (DPH) molecule incorporated inside the lipid bilayer. The interaction of DPH incorporated DMPC membrane with Fluorescein loaded MSN lead to the release of Fluorescein (Fl) dye from the interior pores of MSN systems. The extent of release of Fl and spatial distribution of the DPH molecule has been explored by monitoring steady-state fluorescence intensity and fluorescence lifetime at physiological condition. To investigate the fate of drug molecule released from MSN, fluorescence anisotropy has been used. The drug delivery efficiency of the MSN as a carrier for doxorubicin (DOX), a fluorescent chemotherapeutic drug, has also been investigated at physiological conditions. The study gives a definite confirmation for high uptake and steady release of DOX in primary oral mucosal non-keratinized squamous cells in comparison to naked DOX treatment.

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  • Bioreduction potentials of dried root of Zingiber officinale for a simple green synthesis of silver nanoparticles: Antibacterial studies
    Publication date: December 2017
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 177

    Author(s): J. Judith Vijaya, N. Jayaprakash, K. Kombaiah, K. Kaviyarasu, L. John Kennedy, R. Jothi Ramalingam, Hamad A. Al-Lohedan, Mansoor-Ali V.M., M. Maaza

    Green synthesis of silver nanoparticles (Ag NPs) using an extract of dried Zingiber officinale (ginger) root as a reducing and capping agent in the presence of microwave irradiation was herein reported for the first time. The formation of symmetrical spheres is confirmed from the UV–Visible spectrum of Ag NPs. Fourier transform infra-red spectroscopy confirms the formation of the Ag NPs. X-ray diffraction analysis was utilized to calculate the crystallite size of Ag NPs and the value was found to be 10nm. High-resolution transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the morphology and size of the synthesized samples. The sphere like morphology is confirmed from the images. The purity and crystallinity of Ag NPs is confirmed by energy-dispersive X-Ray analysis and selected area electron diffraction respectively. The electrochemical behavior of the synthesized Ag NPs was assessed by cyclic voltammetry (CV) and shows the redox peaks in the potential range of −1.1 to +1.1V. Agar diffusion method is used to examine the antibacterial activity of Ag NPs. For this purpose, two gram positive and two gram negative bacteria were studied. This single step approach was found to be simple, short time, cost-effective, reproducible, and eco-friendly.

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  • Enhanced biological properties of biomimetic apatite fabricated polycaprolactone/chitosan nanofibrous bio-composite for tendon and ligament regeneration
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Geng Wu, Xuefeng Deng, Jinqi Song, Feiqiang Chen

    The development of tailored nanofibrous scaffolds for tendon and ligament tissue engineering has been a goal of clinical research for current researchers. Here, we establish a formation of novel nanofibrous matrix with significant mechanical and biological properties by electro-spinning process. The fine fibrous morphology of the nanostructured hydroxyapatite (HAp) dispersed in the polycaprolactone/chitosan (HAp-PCL/CS) nanofibrous matrix was exhibited by microscopic (SEM and TEM) techniques. The favorable mechanical properties (load and modulus) were achieved. The load and modulus of the HAp-PCL/CS composite fibers was 250.1N and 215.5MPa, which is very similar to that of standard value of the human tendon and ligament tissues. The cellular responses and biocompatibility of HAp-PCL/CS nanofibrous scaffolds were investigated with human osteoblast (HOS) cells for tendon regeneration and examined the primary osteoblast mechanism by in vitro method. The morphological (FE-SEM and fluorescence) microscopic images clearly exhibited that HOS cells are well attached and flatted on the nanofibrous composites. The HAp dispersed PCL/CS nanofibrous scaffolds promoted higher adhesion and proliferation of HOS cells comparable to the nanofibrous scaffolds without HAp nanoparticles. The physic-chemical and biological properties of the synthesized nanofibrous scaffold were very close to that of normal ligament and tendon in human body. Over all, these studied results confirmed that the prepared nanofibrous scaffolds will be effective biomaterial of tendon ligament regeneration applications.

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  • Photodynamic inactivation of Escherichia coli – Correlation of singlet oxygen kinetics and phototoxicity
    Publication date: Available online 13 November 2017
    Source:Journal of Photochemistry and Photobiology B: Biology

    Author(s): Alexander Müller, Annegret Preuß, Beate Röder

    Photodynamic inactivation (PDI) of bacteria may play a major role in facing the challenge of the ever expanding antibiotic resistances. Here we report about the direct correlation of singlet oxygen luminescence kinetics and phototoxicity in E. coli cell suspension under PDI using the widely applied cationic photosensitizer TMPyP. Through direct access to the microenvironment, the time resolved investigation of singlet oxygen luminescence plays a key role in understanding the photosensitization mechanism and inactivation pathway. Using the homemade set-up for highly sensitive time resolved singlet oxygen luminescence detection, we show that the cationic TMPyP is localized predominantly outside the bacterial cells but in their immediate vicinity prior to photodynamic inactivation. Throughout following light exposure, a clear change in singlet oxygen kinetics indicates a redistribution of photosensitizer molecules to at least one additional microenvironment. We found the signal kinetics mirrored in cell viability measurements of equally treated samples from same overnight cultures conducted in parallel: A significant drop in cell viability of the illuminated samples and stationary viability of dark controls. Thus, for the system investigated in this work – a Gram-negative model bacteria and a well-known PS for its PDI – singlet oxygen kinetics correlates with phototoxicity. This finding suggests that it is well possible to evaluate PDI efficiency directly via time resolved singlet oxygen detection.







  • Green synthesis, characterization and catalytic degradation studies of gold nanoparticles against congo red and methyl orange
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): C. Umamaheswari, A. Lakshmanan, N.S. Nagarajan

    The present study reports, novel and greener method for synthesis of gold nanoparticles (AuNPs) using 5,7-dihydroxy-6-metoxy-3',4'methylenedioxyisoflavone (Dalspinin), isolated from the roots of Dalbergia coromandeliana was carried out for the first time. The synthesized gold nanoparticles were characterized by UV–Vis spectroscopy, high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The observed surface plasmon resonance (SPR) at 532nm in the UV–Vis absorption spectrum indicates the formation of gold nanoparticles. The powder XRD and SAED pattern for synthesized gold nanoparticles confirms crystalline nature. The HR-TEM images showed that the AuNPs formed were small in size, highly monodispersed and spherical in shape. The average particle sizes of the AuNPs are found to be ~10.5nm. The prepared AuNPs were found to be stable for more than 5months without any aggregation. The catalytic degradation studies of the synthesized AuNPs towards degradation of congo red and methyl orange, showed good catalytic in the complete degradation of both the dyes. The reduction catalyzed by gold nanoparticles followed the pseudo-first order kinetics, with a rate constant of 4.5×103 s1 (R2 =0.9959) and 1.7×103 s1 (R2 =0.9918) for congo red (CR) and methyl orange (MO), respectively.

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  • Facile green synthesis of zinc oxide nanoparticles using Ulva lactuca seaweed extract and its evaluation of photocatalytic, antibiofilm and larvicidal activity: impact on mosquito morphology and biofilm architecture
    Publication date: Available online 7 November 2017
    Source:Journal of Photochemistry and Photobiology B: Biology

    Author(s): Ramachandran Ishwarya, Baskaralingam Vaseeharan, Subramanian Kalyani, Balan Banumathi, Marimuthu Govindarajan, Naiyf S. Alharbi, Shine Kadaikunnan, Mohammed N. Al-anbr, Jamal M. Khaled, Giovanni Benelli

    The bioactivity of semiconductor nanocomplexes has been poorly studied in the field of pesticide science. In this research, the synthesis of zinc nanoparticles was accomplished through new effortless green chemistry process using the Ulva lactuca seaweed extract as a reducing and capping agent. The production of U. lactuca-fabricated ZnO nanoparticles (Ul-ZnO Nps) was characterized by powder X-ray diffraction (XRD), UV–visible and Fourier transform infrared (FTIR) spectroscopy, as well as transmission electron microscopy (TEM). The U. lactuca-fabricated ZnO NPs were tested for their photodegradative action against organic dyes, antibiofilm and larvicidal activities. The UV visible absorbance spectrum of Ul-ZnO Nps exhibits the absorbance band at 325nm and TEM image shows average crystallite sizes of nanoparticles at 10–50nm. Methylene blue (MB) dye was efficiently corrupted under sunlight in the presence of Ul-ZnO Nps. Excellent bactericidal activity was shown by the Ul-ZnO Nps on Gram positive (Bacillus licheniformis and Bacillus pumilis) and Gram negative (Escherichia coli, Proteus vulgaris) bacteria. High antibiofilm activity was noted under both dark and sunlight condition. The impact of a single treatment with Ul-ZnO Nps on biofilm architecture was also analyzed by confocal laser scanning microscopy (CLSM) on both Gram positive and Gram negative bacteria. Moreover, Ul-ZnO NPs led to 100% mortality of Aedes aegypti fourth instar larvae at the concentration of 50μg/ml within 24h. The effects of ZnO nanoparticle-based treatment on mosquito larval morphology and histology were also monitored. Overall, based on our results, we believe that the synthesis of multifunctional Ul-ZnO Nps using widely obtaining seaweed products can be promoted as a potential eco-friendly option to chemical methods currently used for nanosynthesis of antimicrobials and mosquito larvicides.

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Научная работа