Search

Singlet oxygen is a toxic chemical but powerful oxidant, exploited in many chemical and biological applications. However, the lifetime of singlet oxygen in air under atmospheric conditions is yet to be known. This has limited safe usage of singlet oxygen in air, despite being a strong antimicrobial agent with the unique property of relaxing to breathable oxygen after serving its purpose. Here, we solve this long-standing problem by combining experimental and theoretical research efforts; we generate singlet oxygen using a photosensitizer at a local source and monitor the time-dependent extent of singlet oxygen reaction with probe molecules at a detector, precisely controlling the detector distance from the source. To explain our experimental results, we employ a theoretical model that fully accounts for singlet oxygen diffusion, radiative and nonradiative relaxations, and the bimolecular reaction with probe molecules at the detector. For all cases investigated, our model, with only two adjustable parameters, provides an excellent quantitative explanation of the experiment. From this analysis, we extract the lifetime of singlet oxygen in the air to be 2.80 s at 23 °C under 1 atm, during which time singlet oxygen diffuses about 0.992 cm. The correctness of this estimation is confirmed by a simple mean-first-passage time analysis of the maximum distance singlet oxygen can reach from the source. We also confirm the sterilization effects of singlet oxygen for distances up to 0.6-0.8 cm, depending on the bacteria strain in question, between the bacteria and the singlet oxygen source.

Photodynamic therapy has been efficiently applied for cancer therapy. Here, we have fabricated the folic acid (FA)- and pheophorbide A (PA)-conjugated FA/PA@Fe3O4 nanoparticle (smart hybrid nanocomposite, SHN) to enhance the photodynamic inactivation (PDI) of specific cancer cells. SHN coated with the PDI agent is designed to have selectivity for the folate receptor (FR) expressed on cancer cells. Structural characteristics and morphology of the fabricated MNPs were studied with X-ray diffraction and scanning electron microscopy. The photophysical properties of SHN were investigated with absorption, emission spectroscopies, and Fourier transform infrared spectroscopy. In addition, the magnetic property of Fe3O4 nanoparticle (MNP) can be utilized for the collection of SHNs by an external magnetic field. The photofunctionality was given by the photosensitizer, PA, which generates reactive oxygen species by irradiation of visible light. Generation of singlet oxygen was directly evaluated with time-resolved phosphorescence spectroscopy. Biocompatibility and cellular interaction of SHN were also analyzed by using various cancer cells, such as KB, HeLa, and MCF-7 cells which express different levels of FR on the surface. Cellular adsorption and the PDI effect of SHN on the various cancer cells in vitro were correlated well with the surface expression levels of FR, suggesting potential applicability of SHN on specific targeting and PDI of FR-positive cancers.

Here, we investigated the bactericidal effects of two types of photoinduced reactive oxygen species (ROS), superoxide anion and singlet oxygen, on bacteria with distinct surface charges. We fabricated photofunctional polymer films (PFPFs) capable of generating both types of ROS, and they were subjected to photodynamic inactivation tests for 12 various strains of Acinetobacter baumannii. The results showed that the type I ROS (superoxide anion) was significantly dependent on the surface charge of the bacteria owing to charge-charge repulsion, while the type II ROS (singlet oxygen) was independent of the surface charge of the bacteria. These results could be significant in enhancing treatment efficiency in the clinical field.

To inactivate methicillin-resistant Staphylococcus aureus (MRSA) with minimum damage to host cells and tissue, target-oriented photofunctional nanoparticles (TOPFNs) were fabricated and characterized. MRSA is a predominant infective pathogen even in hospital and non-hospital environments due to its ability to develop high levels of resistance to several classes of antibiotics through various pathways. To solve this major problem, photodynamic inactivation (PDI) method applies to treat antibiotic-resistant bacteria. PDI involves the photosensitizer (PS) and light with a specific wavelength to be able to apply for a non-invasive therapeutic procedure to treat pathogenic bacteria by inducing apoptosis or necrosis of microorganisms. However, most current PDI researches have suffered from the instability of PDI agents in the biological environment due to the lack of selectivity and low solubility of PDI agents, which leads to the low PDI efficiency. In this study, the TOPFNs were fabricated by an esterification reaction to introduce hematoporphyrin (HP) and MRSA antibody to the surface of Fe3O4 nanoparticles. The TOPFNs were designed as dispersible PDI agent in biological condition, which was effectively used for selectively capturing and killing of MRSA. The capture efficiency TOPFNs was compared with PFNs as a negative control. The results showed that the capture efficiency of TOPFNs and PFNs was 95.55% and 6.43% in MRSA and L-929 cell mixed condition, respectively. And TOPFNs have a selective killing ability for MRSA with minimum damage to L-929 cells. Furthermore, PDI effect of TOPFNs was evaluated on the mice in vivo condition in order to check the possibility of practical medical application.

Stimuli-responsive materials based on donor–acceptor systems have great potential for sensing applications, including in the solid state. Herein, two push–pull-type molecules, 3,6-di(9H-carbazol-9-yl)pyridazine (CzPyr–H) and 3,6-bis(3,6-dimethoxy-9H-carbazol-9-yl)pyridazine (CzPyr–OMe), each of which contain two carbazole donors and a pyridazine acceptor, were designed and synthesized. The photophysical properties of CzPyr–H and CzPyr–OMe were systematically explored with the aim of switching the absorption and emission properties using trifluoroacetic acid (TFA) as an external analyte, thus realizing volatile acid sensing. The protonation of the central pyridazine unit led to a broad absorption band at longer wavelengths owing to intramolecular charge transfer (ICT), and the emission intensity gradually decreased with increasing TFA concentration. Density functional theory calculations of the HOMO–LUMO energy gaps and orbital distributions of CzPyr–H and CzPyr–OMe as well as their protonated forms, CzPyr–H(H+) and CzPyr–OMe(H+), confirmed that charge transfer occurred in the protonated species. In their aggregated solid states, both compounds showed interesting emission properties including aggregation-enhanced emission (AEE). Utilizing their TFA sensitivity and the AEE phenomenon, CzPyr–H and CzPyr–OMe were successfully applied as fluorescent probes for volatile acid detection and as security ink for information encryption on paper.

We report a photofunctional stainless steel (PSS) that has antimicrobial property which is provided by reactive oxygen species (ROS) generated from the photosensitizer (PS). For the fabrication of the photofunctional stainless steel, the photosensitizer of hematoporphyrin (HP) was covalently bonded to the surface of 316L stainless steel (316LSS) through an esterification reaction. The PSS plate was investigated by x-ray photoelectron spectroscopy (XPS), reflectance UV–Vis absorption, and fluorescence spectroscopy. ROS generation from the PSS plate was studied by using the decomposition reaction of 1,3-diphenyl-isobenzofuran (DPBF). The results suggest that the immobilized photosensitizer molecules on the surface of the PSS plate still possess their intrinsic optical and functional properties including the ROS generation. The antimicrobial property of the PSS plate was successfully demonstrated with the decomposition of biofilm and the suppression of the biofilm formation on the surface of the PSS plate.

The principle of photodynamic treatment (PDT) involves the administration of photosensitizer (PS) at diseased tissues, followed by light irradiation to produce reactive oxygen species (ROS). In cells, a moderate increase in ROS plays an important role as signaling molecule to promote cell proliferation, whereas a severe increase of ROS causes cell damage. Previous studies have shown that low levels of ROS stimulate cell growth through PS drugs-treating PDT and nonthermal plasma treatment. However, these methods have side effects which are associated with low tissue selectivity and remaining of PS residues. To overcome such shortcomings, we designed hematoporphyrin-incorporated polyurethane (PU) film induced generation of extracellular ROS with singlet oxygen and free radicals. The film can easily control ROS production rate by regulating several parameters including light dose, PS dose. Also, its use facilitates targeted delivery of ROS to the specific lesion. Our study demonstrated that extracellular ROS could induce the formation of intracellular ROS. In vascular endothelial cells, a moderated increase in intracellular ROS also stimulated cell proliferation and cell cycle progression by accurate control of optimum levels of ROS with hematoporphyrin-incorporated polymer films. This modulation of cellular growth is expected to be an effective strategy for the design of next-generation PDT.

The correlation between the molecular structures of three corrole derivatives (PC: 5,10,15-triphenyl corrole, PFPC: 5,10,15-tris(pentafluorophenyl) corrole, MCPC: 5,10,15-tris(p-methoxycarbonylphenyl)corrole) and their efficiencies for singlet oxygen generation was studied. Introducing electron-withdrawing fluorine atoms into the PC moiety led to a significant enhancement in singlet oxygen generation and facilitated intersystem crossing (ISC) due to enhanced spin-orbit coupling. Cyclic voltammetry experiments revealed a desirable linear relationship between the quenching rate constants and the oxidation potentials of the three corrole derivatives, indicating that the substituent effect is a critical factor governing the oxidation potential of photosensitizers for singlet oxygen generation.

We report a detailed analysis of singlet oxygen generated from the photofunctional polymer film (PFPF) matrix which is the silicone polymer film (PDMS) embedded with a photosensitizer. Activation and deactivation dynamics of singlet oxygen generated from PFPFs were investigated with time-resolved phosphorescence spectroscopy. The singlet oxygen generated from PFPFs was dissipated into three different regions of the polymer matrix; the inside (component A), the surface (component B), and the outside (component C). According to the deactivation dynamics of singlet oxygen in the polymer matrix, the components B and C are expected to be more important for various applications.

Background/aims Far-infrared (FIR) irradiation has been reported to exhibit various biological effects including improvement of cardiovascular function. However, its effect on the differentiation of stem cells has not been studied. Using tonsil-derived mesenchymal stem cells (TMSC), we examined whether and how FIR irradiation affects adipogenic or osteogenic differentiation. Methods TMSC were exposed to FIR irradiation (3-25 μm wavelength) for various times (0, 30, or 60 min), and then adipogenic or osteogenic differentiation was induced for 14 days with its respective commercially available differentiation medium. At the end of the differentiation, the cells were stained using Oil red O or Alizarin red S solution, and the expression of differentiation-specific proteins was analyzed by western blotting. Results FIR irradiation did not alter cell viability or the expression of MSC-specific surface antigens (CD14, CD34, CD45, CD73, CD90, and CD105) in TMSC. However, FIR irradiation significantly inhibited adipogenic differentiation of TMSC, as evidenced by decreased Oil red O staining as well as protein expression of peroxisome proliferator-activated receptor γ and fatty acid binding protein 4. In contrast, FIR irradiation induced osteogenic differentiation, as evidenced by increased Alizarin red S staining as well as protein expression of osteocalcin and alkaline phosphatase. Treatment with heat alone did not inhibit the adipogenic differentiation of TMSC, suggesting that the inhibitory effect on adipogenic differentiation was not due to heat induced by FIR irradiation. However, heat alone did stimulate osteogenic differentiation, but to a lesser extent than FIR irradiation. Furthermore, FIR irradiation increased intracellular Ca²⁺ levels and the activity of protein phosphatase 2B (PP2B) in TMSC. Treatment with cyclosporin A, a specific PP2B inhibitor, reversed the inhibitory effect of FIR irradiation on adipogenic differentiation of TMSC, but had no effect on osteogenic differentiation. Conclusion Our data demonstrate that FIR irradiation inhibits adipogenic differentiation but enhances osteogenic differentiation of TMSC; the inhibitory effect on adipogenic differentiation is non-thermal and mediated at least in part by activation of Ca²⁺-dependent PP2B.

This study demonstrates the application feasibility of electrochemical impedance spectroscopy (EIS) in measuring estrogen (17β-estradiol) in gas phase. The present biosensor gives a linear response (R2=0.999) for 17β-estradiol vapor concentration from 3.7 ng/L to 3.7 × 10−4 ng/L with a limit of detection (3.7 × 10−4 ng/L). The results show that the fabricated biosensor demonstrates better detection limit of 17β-estradiol in gas phase than the previous report with GC-MS method. This estrogen biosensor has many potential applications for on-site detection of a variety of endocrine disrupting compounds (EDCs) in the gas phase.

We report bactericidal effect of photosensitizer (H2TPP: 5,10,15,20-tetraphenyl-21H,23H-porphyrin) through non-uptake pathway and efficacy of the photofunctional silicon polymer to the decomposition of the formed biofilm and the suppression of the biofilm formation. The photofunctional silicon polymer (PSP), which is the silicon polymer embedded with a photosensitizer, is fabricated by a simple solvent swell-encapsulation-shrink method. Reactive oxygen generation from PSP was confirmed by using the decomposition reaction of 1,3-diphnyl-isobenzofuran (DPBF). Also, singlet oxygen generation which is one of the reactive oxygen species (ROS) from PSP is directly confirmed with time and wavelength resolved singlet oxygen phosphorescence spectroscopy. For the influence study of ROS under the non-uptake condition of photosensitizer (PS to bacteria), photodynamic inactivation (PDI) effect of PSP is evaluated for Gram-positive, Gram-negative bacteria, and fungi. Those microorganisms were inactivated by PSP within 1 h under the given power of laser light (63.7 mW/cm2). Among the bacteria, especially, Staphylococcus aureus as the Gram-positive bacteria were completely disinfected under the given experimental condition. Furthermore, PSP successfully demonstrates the decomposition of the formed biofilm and the suppression of the biofilm formation with green light emitting diode (GLED, 3.5 mW/cm2, λmax = 517 nm, FWHM = 37 nm), which shows the practical application possibility of bactericidal material.

Under the condition of femtosecond impulsive nonlinear optical irradiation, the bright and narrowed blue emission of silicon nanocrystal was observed. This synthetic method produced very small (~ 4 nm) oxide-capped silicon nanocrystal having probably ultra small emitting core (~ 1 nm) inferred from luminescence. By controlling the stirring condition, very high efficiencies of luminescence ( 4 fold higher) were obtained compared with the other conventional femtosecond laser fragmentation methods, which was attributed to the differences in hydration shell structure during the femtosecond laser induced irreversible phase transition reaction. When we properly adjusted the irradiation times of the white light continuum and stirring condition, very homogeneous luminescent silicon nanocrystal bands having relatively sharp lineshape were obtained, which can be attributable to the luminescent core site isolated and free from the surface defects. The field of silicon semiconductor nanocrystals is one of the active research areas in which a wide range of industrial applications including solar cells, sensors, secondary battery unit, and PDT sensitizer in nanomedine have been investigated 1-8 and is also expected to have a very promising role in the future informatics like the quantum computing 9 . Especially, silicon is one of the few elements providing nontoxic, earth abundant and environmentally- friendly characters, and has dominated the microelectronics industry due to their unique physicochemical properties. Therefore, in practical applications such as optoelectronics, the fabrication of reliable and functional silicon nanocrystal having homogeneous optical properties is very important future challenge 10-22 . Until recently, considerable

This study was performed to investigate the prevalence and molecular epidemiology of Pseudomonas aeruginosa isolates from Korea that produce enzymes with extended-spectrum (ES) activity to β-lactams. A total of 205 non-duplicate P. aeruginosa clinical isolates were collected from 18 university hospitals in Korea. PCR and sequencing experiments were performed to identify genes encoding β-lactamases. PCR mapping and sequencing of the regions surrounding the β-lactamase genes were performed. Multilocus sequence typing experiments were performed. The most common sequence type (ST) was ST235 (n = 96), and 2 single-locus variants of ST235, ST1015 (n = 1) and ST1162 (n = 1), were also identified. These 3 STs were grouped as a clonal complex (CC), CC235. The remaining 107 isolates were identified as 59 different STs. Isolates belonging to CC235 showed higher rates of non-susceptibility to imipenem (85.4% versus 47.7%) and meropenem (92.7% versus 52.3%) compared to non-CC235 isolates. All the metallo-β-lactamase (MBL)–producing isolates were identified as CC235, except for 1 ST591. Genes encoding OXA-17 and OXA-142 were detected in 1 isolate and 4 isolates of CC235, respectively; while the bla SHV-12 gene was detected in 4 non-CC235 isolates. Class A and D β-lactamases with ES activity play a role in acquiring ceftazidime resistance in P. aeruginosa in Korea. Production of IMP-6 and VIM-2 MBLs is the main mechanisms in acquiring resistance to ceftazidime and carbapenems in P. aeruginosa isolates in Korea. Clonal spread of P. aeruginosa CC235 may be an important conduit for the dissemination of MBL genes in Korea.

Hybridization with conductive 2D nanosheets (NSs) attracts plenty of research activities because of its effectiveness for improving the photocatalyst performance of diverse semiconductors. Here, versatile roles of conductive NSs in hybrid-type photocatalysts are systematically investigated with three representative conductive 2D NSs to synthesize highly efficient visible light-active photocatalysts. Among several conductive NS-based nanohybrids, the RuO2 NS-based nanohybrid exhibits the highest photocatalytic activities. Based on systematic spectroscopic analyses, polar RuO2 NS appears to be more effective as electron reservoir, photosensitizer, cocatalyst and charge carrier pathway in hybrid-type photocatalyst than MoS2 and graphene NSs. The high efficiency of RuO2 NS as hybridization matrix is attributable to the high surface hydrophilicity, high surface bond polarity, and enhanced interfacial electronic coupling of this hydrophilic NS with semiconductor. The present study underscores that hydrophilic conductive metal oxide NS can act as the most efficient hybridization matrix for exploring high-performance photocatalysts with strong interfacial electronic coupling.

Background & objectives: PFGE, rep-PCR, and MLST are widely used to identify related bacterial isolates and determine epidemiologic associations during outbreaks. This study was performed to compare the ability of repetitive sequence-based PCR (rep-PCR) and pulsed-field gel electrophoresis (PFGE) to determine the genetic relationships among Escherichia coli isolates assigned to various sequence types (STs) by two multilocus sequence typing (MLST) schemes. Methods: A total of 41 extended-spectrum β-lactamase- (ESBL-) and/or AmpC β-lactamase-producing E. coli clinical isolates were included in this study. MLST experiments were performed following the Achtman′s MLST scheme and the Whittam′s MLST scheme, respectively. Rep-PCR experiments were performed using the DiversiLab system. PFGE experiments were also performed. Results: A comparison of the two MLST methods demonstrated that these two schemes yielded compatible results. PFGE correctly segregated E. coli isolates belonging to different STs as different types, but did not group E. coli isolates belonging to the same ST in the same group. Rep-PCR accurately grouped E. coli isolates belonging to the same ST together, but this method demonstrated limited ability to discriminate between E. coli isolates belonging to different STs. Interpretation & conclusions: These results suggest that PFGE would be more effective when investigating outbreaks in a limited space, such as a specialty hospital or an intensive care unit, whereas rep-PCR should be used for nationwide or worldwide epidemiology studies.

We investigated the antimalarial effect of photodynamic inactivation (PDI) coupled with magnetic nanoparticles (MNPs) as a potential strategy to combat the emergence of drug-resistant malaria and resurgence of malaria after treatment. Because the malarial parasite proliferates within erythrocytes, PDI agents need to be taken up by erythrocytes to eradicate the parasite. We used photofunctional MNPs as the PDI agent because nanosized particles were selectively taken up by Plasmodium-infected erythrocytes and remained within the intracellular space due to the enhanced permeability and retention effect. Also, the magnetism of Fe3O4 nanoparticles can easily be utilized for the collection of photofunctional nanoparticles (PFNs), and the uptaken PFNs infected the erythrocytes after photodynamic treatment with external magnetics. Photofunctionality was provided by a photosensitizer, namely, pheophorbide A, which generates reactive oxygen species (ROS) under irradiation. PAs were covalently bonded to the surface ...

We report the fabrication of photofunctional Co-Cr alloy plate that is prepared by a simple modification process for photodynamic application. Photoinduced functionality is provided by the photosensitizer of hematoporphyrin (Hp) that initially generates reactive oxygen species (ROS) such as superoxide anion radical and singlet oxygen. The photosensitizer with carboxyl group was chemically bonded to the surface of the Co-Cr alloy plate by esterification reaction. Microstructure and elemental composition of the Co-Cr alloy plate were checked with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS). Fabrication of the photofunctionality of the Co-Cr alloy plate was confirmed with X-ray photoelectron spectroscopy (XPS), reflectance UV-Vis absorption, and emission spectroscopy. Reactive oxygen generation from the photofunctional Co-Cr alloy plate was confirmed by using the decomposition reaction of 1,3-diphenylisobenzofuran (DPBF). The results suggest that the immobilized photosensitizer molecules on the surface of Co-Cr alloy plate still possess their optical and functional properties including reactive oxygen generation. To open the possibility for its application as a photodynamic material to biological system, the fabricated photofunctional Co-Cr alloy is applied to the decomposition of smooth muscle cells.

Plasma surface modifications of polymer scaffolds using biomolecules such as oxygen, nitrogen, and other active grafting molecules have been studied to enhance biological responses such as cell attachment, spreading, and proliferation. According to the reports, nitrogen grafting requires corrosive or mixture gas environment, or post treatment. This study aimed to evaluate a simple atmospheric pressure plasma surface modification in order to graft nitrogen derivatives and to promote biological responses. In this study, a polycarprolactone (PCL) film was modified within 10 min by argon atmospheric pressure discharge (Ar-APGD). Excited argon atoms, nitrogen atoms, oxygen atoms, and hydroxyl functional groups were observed from the optical emission spectra of the discharge. Decreased carbonyl functional groups and ether functional groups were observed; notably, immobilized nitrogen was observed on the PCL surface after the Ar-APGD treatment. Promoted neonatal Human Dermal Fibroblast (nHDF) growth patterns were observed on the Ar-APGD-treated surface.

The nanoporous alumina membranes (NAMs) were fabricated by a two-step aluminium anodic oxidation process. The fabricated NAMs have controllable pore diameters (40–80 nm) and unidirectionally ordered pore direction. The surface of the NAM was modified with the organo-silane agent (APTES: (aminopropyl)triethoxysilane) to induce ionic bonding between the NAM and the photosensitizer (TSPP: tetrakis(p-sulfonatophenyl)porphyrin). The morphology and chemical nature of the surface modified NAM were studied by field emission scanning electron microscope (FE-SEM), FT-IR spectra, and thermo gravimetric analysis (TGA). Furthermore, this singlet oxygen generating nanoporous membranes (SGNMs) were investigated, in detail, to understand their photophysical properties and the singlet oxygen generation efficiency which were the essential factors for their applications. Steady-state spectroscopies and nanosecond laser induced time-resolved spectroscopy were applied to get information on all photophysical properties including the lifetime of singlet oxygen which depended on the pore diameter of the SGNM.

We report a novel photofunctional magnetic nanoparticle that is strategically designed and prepared by simple modification process. Photofunctionality is provided by the photosensitizer (PS) of [5,15-bis(phenyl)-10,20-bis(4-methoxycarbonylphenyl)porphyrin]platinum that generates singlet oxygen in high quantum yield. The PS molecules are covalently bonded to the surface of magnetic nanoparticles. Microstructure and magnetic and photophysical properties of the photofunctional magnetic nanoparticles are investigated by transmission electron microscopy, vibrating sample magnetometry, and time-resolved spectroscopic methods. The results show that the immobilized PS molecules retain their optical and functional properties including the high efficiency of singlet oxygen generation. Generation quantum yield (ΦΔ) and releasing yield (ηΔ) of singlet oxygen from the prepared photofunctional magnetic nanoparticles are 0.47 and 0.42, respectively. Furthermore, the photofunctional magnetic nanoparticles have good solub...

In this work, mesoporous carbon nanofibers (MCNF) were synthesized by using a template of mesoporous silicate nanofibers within anodic aluminum oxide (AAO) film and furfuryl alcohol for the carbon source at the carbonization temperatures (600, 900, and 1200 °C). Due to the easy control nature of pore size and thickness of AAO film, the diameter and length of MCNF can easily be controlled. The MCNF pyrolyzed at 1200 °C shows the highest BET surface area. The surface area is discussed with the structural properties associated. Also, hydrogen uptake capacity of MCNF is measured to examine the nanofibers for the potential application as a hydrogen storage media. Among them, MCNF carbonized at 1200 °C shows 0.73 wt.% of the highest hydrogen uptake at 77 K and 0.1 MPa. Results of the study indicate that the capacity of the MCNF for hydrogen storage shall increase as the carbonization temperature increases. The structural property and the surface area of MCNFs depending on carbonization temperature were discussed with their hydrogen uptake efficiency.

Photodynamic Therapy (PDT) is a promising approach for killing microorganism and especially for the inactivation of antibiotic-resistant strains. The photodynamic process rapidly generates reactive oxygen species (ROS) as for instance peroxides, hydroxyl radicals, superoxide ions, and singlet oxygen. Among them, the singlet oxygen is considered to be a major causative agent of cellular damage in photodynamic process. Due to advantage of the cytotoxic effect of PDT on bacteria, the PDT method has been one of the most appropriate tools to prevent the microbes which result in biofilm formation. This work describes a method of singlet oxygen generating nanolayer coating on NiTi alloy which shows a good biocompatibility. The 5,10,15-triphenyl-20-(4-carboxyphenyl)-porphyrin] platinum (PtCP) functional nanolayer coatings were prepared in two steps. In the first step, Al coating was prepared on biomedical NiTi alloy substrate by DC magnetron sputtering, and then this coated substrate alloy was immersed into hot water to form Al 2 O 3 coatings. In the second step, a photosensitizer (PS) with carboxyl group was chemically attached to the hydroxyl-terminated Al 2 O 3 coatings by a direct esterification method. The microstructure and the elemental and phase composition of the coating were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD). Results from this study show that the PtCP functional nanolayer coating is composed of many perpendicular nanosheet structures. These very thin nanosheet structures with the thickness of a few nanometers mainly show amorphous phase. The singlet oxygen generation efficiency of the PS being chemically bonded on these nanosheets was detected by an indirect chemical method by using the decomposition of 1,3-diphenyl-isobenzofuran (DPBF).

A new photo-catalyst of [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] platinum was synthesized and its photophysical study revealed that it had a high quantum yield of singlet oxygen generation. As an application study, a stereo-specific synthesis of (+)-deoxoartemisinin was performed. The induced high triplet quantum yield (0.96 ± 0.03) of [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] resulted the high singlet oxygen quantum yield of 0.90 ± 0.04. The photo-catalytic effect was compared with that of methylene blue (MB) which was generally used as a photo-catalyst for these types of stereo-specific syntheses of organic compounds. The yield of synthesized (+)-deoxoartemisinin was correlated with singlet oxygen quantum yield.

The photocatalytic activity and photostability of CdS quantum dot (QD) can be remarkably enhanced by hybridization with Rh-substituted layered titanate nanosheet even at very low Rh substitution rate (

Reactive oxygen species (ROS) play an important role in cellular signaling as second messengers. However, studying the role of ROS in physiological redox signaling has been hampered by technical difficulties in controlling their generation within cells. Here, we utilize two inert components, a photosensitizer and light, to finely manipulate the generation of intracellular ROS and examine their specific role in activating dendritic cells (DCs). Photoswitchable generation of intracellular ROS rapidly induced cytosolic mobilization of Ca(2+), differential activation of mitogen-activated protein kinases, and nuclear translocation of NF-κB. Moreover, a transient intracellular ROS surge could activate immature DCs to mature and potently enhance migration in vitro and in vivo. Finally, we observed that intracellular ROS-stimulated DCs enhanced antigen specific T-cell responses in vitro and in vivo, which led to delayed tumor growth and prolonged survival of tumor-bearing mice when immunized with a specific tumor antigen. Therefore, a transient intracellular ROS surge alone, if properly manipulated, can cause immature DCs to differentiate into a motile state and mature forms that are sufficient to initiate adaptive T cell responses in vivo.

Pheophorbide-a derivatives have been reported to be potential photosensitizers for photodynamic therapy (PDT). In this study, photophysics of pheophorbide-a derivatives (PaDs) were investigated along with their photodynamic tumoricidal effectin vitro. PaDs were modified by changing the coil length and/or making the hydroxyl group (–OH) substitutions. Their photophysical properties were studied by steady-state and time-resolved spectroscopic methods. The photodynamic tumoricidal effect was evaluated in the mouse breast cancer cell line (EMT6). Lifetime and quantum yield of fluorescence and quantum yields of triplet state and singlet oxygen were studied to determine the dynamic energy flow. The coil length of the substituted alkyl group did not significantly affect the spectroscopic properties. However, the substitution with the hydroxyl group increased the quantum yields of the triplet state and the singlet oxygen due to the enhanced intersystem crossing. In order to check the application possibility as a photodynamic therapy agent, the PaDs with hydroxyl group were studied for the cellular affinity and the photodynamic tumoricidal effect of EMT6. The results showed that the cellular affinity and the photodynamic tumoricidal effect of PaDs with the hydroxyl group depended on the coil-length of the substituted alkyl group.

Fabrication and photophysical study of photofunctional nanoporous alumina membrane (PNAM) were performed, and its application of photodynamic antimicrobial chemotherapy (PACT) was investigated. Nanoporous alumina membrane (NAM) was fabricated by two-step aluminium anodic oxidation process. Surface of the fabricated NAM was modified with organo-silane agent to induce covalent bonding between NAM and a photosensitizer (PtCP: [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] platinum). PtCP was covalently bonded to the surface of the modified NAM by nucleophilic acyl substitution reaction process. The morphology and the photophysical properties of the fabricated PNAM were confirmed with field emission scanning electron microscope (FE-SEM), steady-state spectroscopies, and nanosecond laser-induced time-resolved spectroscopy. For the efficacy study of PNAM in PACT, an enveloped animal virus, vesicular stomatitis virus (VSV), was utilized as a target organism. Antiviral effect of the PNAM-PACT was measured by the extent of suppression of plaque-forming units (PFU) after the light irradiation. In the cultures inoculated with PACT-treated VSV, the suppression of PFU was prominent, which demonstrates that PNAM is a potential bio clean-up tool.

Advanced biomaterials should also be bioactive with regard to desirable cellular responses, such as selective protein adsorption and cell attachment, proliferation, and differentiation. To enhance cell-material interactions, surface modifications have commonly been performed. Among the various surface modification approaches, atmospheric pressure glow discharge plasma has been used to change a hydrophobic polymer surface to a hydrophilic surface. Poly(L-lactic acid) (PLLA)-derived scaffolds lack cell recognition signals and the hydrophobic nature of PLLA hinders cell seeding. To make PLLA surfaces more conducive to cell attachment and spreading, surface modifications may be used to create cell-biomaterial interfaces that elicit controlled cell adhesion and maintain differentiated phenotypes. In this study, (He) gaseous atmospheric plasma glow discharge was used to change the characteristics of a 3D-type polymeric scaffold from hydrophobic to hydrophilic on both the outer and inner surfaces of the scaffold...

Novel multifunctional magnetic particles (MMPs) conjugated with photosensitizer and vancomycin were fabricated by surface modification of Fe(3)O(4) particles. The capacities to target, capture and inactivate pathogenic bacteria and good biocompatibility suggest that the MMPs have great potentials as photodynamic inactivation agents for serious bacterial contamination.

We report the fabrication of a novel titania membrane of the dual-pore system that is strategically designed and prepared by a two-step replication process and sol-gel reaction. The primary nanoporous channel structure is fabricated by the cage-like PMMA template (CPT) obtained from the nanoporous alumina membrane and the secondary mesoporous structure is formed by the sol-gel reaction of the lyotropic precursor solution within the CPT. Furthermore the mesoporous titania membrane (MTM) frame consists of the titania nanoparticles of 10-12 nm in diameter. Morphology and structural properties of the MTM are investigated by field emission scanning electron microscopy, high resolution transmission electron microscopy, x-ray diffraction and Brunauer-Emmett-Teller surface area. The photocatalytic activity and the solar energy properties of the MTM are characterized by UV-vis spectrophotometer, spectrofluorometer and photoinduced I-V measurement. The photocatalytic test indicates that the MTM has higher efficiency than the commercial P25 with a good recyclability due to its large-scale membrane style and the preliminary result on the solar cell application shows a solar energy conversion efficiency of 3.35% for the dye-sensitized solar cell utilizing the MTM.

We have synthesized mesoporous TiO2 nanofibers loaded with Au nanoparticles (MTNF-Au) and fabricated single nanofiber-based devices. MTNF-Au devices exhibited surface plasmon enhanced photoconductance under visible light, whereas MTNF devices without Au nanoparticles did not. Moreover, Coulomb oscillations were observed at 4.2 K in MTNF-Au devices, indicating that Au nanoparticles embedded in MTNF-Au played a role of Coulomb islands. These results suggested that the enhanced photoconductance was ascribed to electron tunneling of hot electrons generated by the surface plasmon resonance.

Polymer–metal complex micelles (PMCMs) containing cisplatin (cis-dichlorodiammineplatinum(II), CDDP), an anticancer drug, were prepared by a coordination bond of CDDP to dendrimer phthalocyanine (DPc) and poly(ethylene glycol)-block-poly(L-aspartic acid) (PEG-PLAn; molecular weight of PEG segment = 12 000 g mol−1; polymerization degrees of aspartic acid segment n = 68, 96). Transmission electron microscopy (TEM) and laser light scattering (LLS) exhibited formation of unimodal PMCM68 and PMCM96 with average sizes of 108 and 135 nm, respectively. PMCMs were very stable in 10 mM phosphate buffer solution (PBS) without NaCl to maintain their shape and size over a month. However, PMCMs slowly released CDDP when they were incubated in physiological saline PBS solution at 37 °C. Upon laser light irradiation, generation of singlet oxygen was detected by photo-luminescence observation. The PMCMs would be effective nano-devices for anticancer drug carriers with sustained drug release and photodynamic therapy (PDT).