The Syntheses of Chromium Aluminum Carbide (Cr2AlC) MAX Phase and Cr2CTx MXene and Investigation of Their Antimicrobial Properties.

Chromium aluminum carbide (Cr2AlC) MAX phase and Cr2CTx (MXene-Cr) were synthesized by the pressureless sintering method and hydrothermal method, respectively. In addition to this, the free radical scavenging activities (FRSA) of MAX-Cr phase and MXene-Cr compounds were tested and compared with ascorbic acid and trolox as standard compounds. The obtained FRSA results of MAX-Cr phase and MXene-Cr were 42.82 and 59.64%, respectively, at 100 mg/L concentration. MXene-Cr showed a 66.90% inhibitory effect on α-amylase at 200 mg/L. The DNA nuclease activity of compounds was determined to be extremely satisfactory at 50, 100, and 200 mg/L concentrations. Moreover, the prepared MAX-Cr phase and MXene-Cr were investigated for antimicrobial activity against six bacterial and two fungal strains by the broth microdilution method. Compounds provided more significant inhibition against Gram-positive bacteria than Gram-negative bacteria and fungi. MAX-Cr phase and MXene-Cr almost completely inhibited microbial cell viability at a 25 mg/L concentration. Additionally, MXene-Cr showed 89.86% and 87.01% antibiofilm activity against S. aureus and P. aeruginosa, respectively, while the antibiofilm activity of the MAX-Cr phase was over 90%.

Development of a Cr2AlC MAX phase/g-C3N4 composite-based electrochemical sensor for accurate cabotegravir determination in pharmaceutical and biological samples.

A highly sensitive electrochemical sensor is reported that employs a modified electrode for the precise measurement of cabotegravir, a potent anti-HIV drug. Cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) were utilized for this purpose. Electrode modification involved the immobilization of Cr2AlC MAX phase/g-C3N4 onto a glassy carbon electrode (GCE) to enhance its electrocatalytic activity and selectivity for cabotegravir detection. Under the optimal experimental conditions, the working potential (vs. Ag/AgCl) was to 0.93 V. The developed sensor exhibited a good linear relationship in the range 0.05 µM to 9.34 µM with a low limit of detection of 4.33 nM, signifying its exceptional sensitivity. Additionally, it demonstrated successful cabotegravir detection in pharmaceutical formulations and biological samples, achieving an RSD below 3.0%. The recoveries fell within the range 97.7 to 102%, confirming the sensor's potential for real-sample applications. This innovative electrochemical sensor represents a significant advancement, providing a simple, reliable, and sensitive tool for the accurate measurement of cabotegravir. Its potential applications include optimizing drug dosages, monitoring treatment responses, and supporting the development of cabotegravir-based pharmaceutical products, thereby contributing to advancements in HIV therapy and prevention strategies.

Antibacterial and antioxidant activity of gold and silver nanoparticles in dextran-polyacrylamide copolymers.

Search for new antimicrobial agents is of great significance due to the issue of antimicrobial resistance, which nowadays has become more important than many diseases. The aim of this study was to evaluate the toxicity and biological effects of a dextran-graft-polyacrylamide (D-PAA) polymer-nanocarrier with/without silver or gold nanoparticles (AgNPs/D-PAA and AuNPs/D-PAA, respectively) to analyze their potential to replace or supplement conventional antibiotic therapy. The toxicity of nanocomplexes against eukaryotic cells was assessed on primary dermal fibroblasts using scratch, micronucleus and proliferation assays. DPPH (2,2-diphenyl-1-picrylhydrazylradical) assay was used to evaluate the antioxidant capacity of D-PAA, AgNPs/D-PAA and AuNPs/D-PAA. DNA cleavage, antimicrobial and biofilm inhibition effects of nanocomplexes were investigated. Nanocomplexes were found to be of moderate toxicity against fibroblasts with no genotoxicity observed. AgNPs/D-PAA reduced motility and proliferation at lower concentrations compared with the other studied nanomaterials. AgNPs/D-PAA and AuNPs/D-PAA showed radical scavenging capacities in a dose-dependent manner. The antimicrobial activity of AgNPs/D-PAA against various bacteria was found to be much higher compared to D-PAA and AuNPs/D-PAA, especially against E. hirae, E. faecalis and S. aureus, respectively. D-PAA, AgNPs/D-PAA and AuNPs/D-PAA showed DNA-cleaving and biofilm inhibitory activity, while AgNPs/D-PAA displayed the highest anti-biofilm activity. AgNPs/D-PAA and AuNPs/D-PAA were characterized by good antimicrobial activity. According to the findings of the study, AgNPs/D-PAA and AuNPs/D-PAA can be evaluated as alternatives for the preparation of new antimicrobial agents, the fight against biofilms, sterilization and disinfection processes. Our findings confirm the versatility of nanosystems based on dextran-polyacrylamide polymers and indicate that AgNPs/D-PAA and AuNPs/D-PAA can be evaluated as alternatives for the preparation of novel antimicrobial agents.

Synthesis of PES membranes modified with polyurethane-paraffin wax nanocapsules and performance of bovine serum albumin and humic acid rejection.

Membrane fouling is a serious handicap of membrane-based separation, as it reduces permeation flux and hence increases operational and maintenance expenses. Polyurethane-paraffin wax (PU/PW) nanocapsules were integrated into the polyethersulfone membrane to manufacture a composite membrane with higher antifouling and permeability performance against humic acid (HA) and bovine serum albumin (BSA) foulants. All manufactured membranes were characterized by scanning electron microscopy (SEM), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and contact angle. The contact angle of the pristine polyethersulfone (PES) membrane was measured 73.40 ± 1.32. With the embedding of nanocapsules, the contact angle decreased to 64.55 ± 1.23 for PES/PU/PW 2.0 wt%, and the pure water flux of all composite membranes increased when compared to pristine PES. The pristine PES membrane also has shown the lowest steady-state fluxes at 45.84 and 46.59 L/m2h for BSA and HA, respectively. With the increase of PU/PW nanocapsule ratio from 0.5 to 1.0 wt%, steady-state fluxes increased from 51.96 to 71.61 and from 67.87 to 98.73 L/m2h, respectively, for BSA and HA. The results depicted that BSA and HA rejection efficiencies of PU/PW nanocapsules blended PES membranes increased when compared to pristine PES membranes.

Boron-based magnesium diboride nanosheets preparation and tested for antimicrobial properties for PES membrane.

Antimicrobial resistance to antibiotics for current bacterial infection treatments is a medical problem. 2D nanoparticles, which can be used as both antibiotic carriers and direct antibacterial agents due to their large surface areas and direct contact with the cell membrane, are important alternatives in solving this problem. This study focuses on the effects of a new generation borophene derivative obtained from MgB2 particles on the antimicrobial activity of polyethersulfone membranes. MgB2 nanosheets were created by mechanically separating magnesium diboride (MgB2) particles into layers. The samples were microstructurally characterized using SEM, HR-TEM, and XRD methods. MgB2 nanosheets were screened for various biological activities such as antioxidant, DNA nuclease, antimicrobial, microbial cell viability inhibition, and antibiofilm activities. The antioxidant activity of nanosheets was 75.24 ± 4.15% at 200 mg/L. Plasmid DNA was entirely degraded at 125 and 250 mg/L nanosheet concentrations. MgB2 nanosheets exhibited a potential antimicrobial effect against tested strains. The cell viability inhibitory effect of the MgB2 nanosheets was 99.7 ± 5.78%, 99.89 ± 6.02%, and 100 ± 5.84% at 12.5 mg/L, 25 mg/L, and 50 mg/L, respectively. The antibiofilm activity of MgB2 nanosheets against S. aureus and P. aeruginosa was observed to be satisfactory. Furthermore, a polyethersulfone (PES) membrane was prepared by blending MgB2 nanosheets from 0.5 wt to 2.0 wt %. Pristine PES membrane also has shown the lowest steady-state fluxes at 30.1 ± 2.1 and 56.6 L/m2h for BSA and E. coli, respectively. With the increase of MgB2 nanosheets amount from 0.5 to 2.0 wt%, steady-state fluxes increased from 32.3 ± 2.5 to 42.0 ± 1.0 and from 15.6 ± 0.7 to 24.1 ± 0.8 L/m2h, respectively for BSA and E. coli. E. coli elimination performance of PES membrane coated with MgB2 nanosheets at different rates and the membrane filtration procedure was obtained from 96% to 100%. The results depicted that BSA and E. coli rejection efficiencies of MgB2 nanosheets blended PES membranes increased when compared to pristine PES membranes.

Antifouling and antibacterial performance evaluation of polyethersulfone membranes modified with AZ63 alloy.

Antibacterial membranes have attracted researchers' interest in recent years as a possible approach for dealing with biofouling on the membrane surface. This research aims to see if blending AZ63 Mg alloy into a polyethersulphone (PES) membrane can improve antifouling and separation properties. The composite membranes' pure water flux continued to increase from pristine PES to PES/AZ63 2.00 wt%. The results showed that PES/AZ63 2.00 wt% membrane supplied the highest permeate flux of E. coli. The steady-state fluxes of AZ63 composite membranes were 113.24, 104.38 and 44.79 L/m2h for PES/AZ63 2.00 wt%, 1.00 wt%, and 0.50 wt%, respectively. The enhanced biological activity of AZ63 was studied based on antioxidant activity, DNA cleavage, antimicrobial, anti-biofilm, bacterial viability inhibition and photodynamic antimicrobial therapy studies. The maximum DPPH scavenging activity was determined as 81.25% with AZ63. AZ63 indicated good chemical nuclease activity and also showed moderate antimicrobial activity against studied strains. The highest biofilm inhibition of AZ63 was 83.25% and 71.63% towards P. aeruginosa and S. aureus, respectively. The cell viability inhibition activity of AZ63 was found as 96.34% against E. coli. The photodynamic antimicrobial therapy results displayed that AZ63 demonstrated 100% bacterial inhibition when using E. coli.

Antimicrobial activity and cytotoxicity study of cerium oxide nanoparticles with two different sizes.

The control over bacterial diseases requires the development of novel antibacterial agents. The use of antibacterial nanomedicines is one of the strategies to tackle antibiotic resistance. The study was designed to assess the antimicrobial activity of cerium oxide (CeO2 ) nanoparticles (NP) of two different sizes (CeO2 NP1 [1-2 nm] and CeO2 NP2 [10-12 nm]) and their cytotoxicity towards eukaryotic cells. The antimicrobial activity, effects of nanoparticles on DNA cleavage, microbial cell viability, and biofilm formation inhibition were analyzed. The impact of cerium oxide nanoparticles on eryptosis of erythrocytes was estimated using annexin V staining by flow cytometry. The newly synthesized CeO2 NP1 and CeO2 NP2 displayed moderate antimicrobial activities. CeO2 NP1 and CeO2 NP2 exhibited single-strand DNA cleavage ability. CeO2 NPs were found to show 100% microbial cell viability inhibition at a concentration of 500 mg/L. In addition, CeO2 NP1 and CeO2 NP2 inhibited the biofilm formation of S. aureus and P. aeruginosa. Larger cerium oxide nanoparticles were found to be less toxic against erythrocytes compared with the smaller ones. CeO2 nanoparticles demonstrate moderate antimicrobial activity and low cytotoxicity towards erythrocytes, which make them promising antibacterial agents.

Development of antimicrobial nanocomposite scaffolds via loading CZTSe quantum dots for wound dressing applications.

The antimicrobial properties of scaffolds designed for use in wound healing are accepted as an important factor in the healing process to accelerate the wound healing process without causing inflammation. For this purpose, chitosan-polyvinyl alcohol composite membranes loaded with Cu2ZnSnSe4quantum dots (CZTSe QDs) as an antibacterial and cytocompatible biomaterial to regulate the wound healing process were produced. CZTSe QDs particles were synthesized under hydrothermal conditions. Polymer-based nanocomposites with different concentrations of the synthesized nanoparticles were produced by the solvent casting method. After detailed physicochemical and morphological characterizations of CZTSe QDs and composite membranes, antibacterial activities and cell viability were extensively investigated against gram-positive and gram-negative bacterial and yeast strains, and L929 mouse fibroblast cells lines, respectively. The results show that the preparation of composite scaffolds at a QDs concentration of 3.3% by weight has the best antimicrobial activity. Composite scaffold membranes, which can be obtained as a result of an easy production process, are thought to have great potential applications in tissue engineering as wound dressing material due to their high mechanical properties, wettability, strong antibacterial properties and non-toxicity.

Antimicrobial Effects of Nanostructured Rare-Earth-Based Orthovanadates.

The search for novel antimicrobial agents is of huge importance. Nanomaterials can come to the rescue in this case. The aim of this study was to assess the cytotoxicity and antimicrobial effects of rare-earth-based orthovanadate nanoparticles. The cytotoxicity against host cells and antimicrobial activity of LaVO4:Eu3+ and GdVO4:Eu3+ nanoparticles were analyzed. Effects of nanomaterials on fibroblasts were assessed by MTT, neutral red uptake and scratch assays. The antimicrobial effects were evaluated by the micro-dilution method estimating the minimum inhibitory concentration (MIC) of nanoparticles against various strains of microorganisms, DNA cleavage and biofilm inhibition. GdVO4:Eu3+ nanoparticles were found to be less toxic against eukaryotic cells compared with LaVO4:Eu3+. Both nanoparticles exhibited antimicrobial activity and the highest MIC values were 64 mg/L for E. hirae, E. faecalis and S. aureus shown by GdVO4:Eu3+ nanoparticles. Nanoparticles demonstrated good DNA cleavage activity and induction of double-strand breaks in supercoiled plasmid DNA even at the lowest concentrations used. Both nanoparticles showed the biofilm inhibition activity against S. aureus at 500 mg/L and reduced the microbial cell viability. Taken the results of host toxicity and antimicrobial activity studies, it can be assumed that GdVO4:Eu3+ nanoparticles are more promising antibacterial agents compared with LaVO4:Eu3+ nanoparticles.

Water-Based Synthesis of Copper Chalcogenide Structures and Their Photodynamic Immunomodulatory Activities on Mammalian Macrophages.

Generation of novel and versatile immunomodulatory agents that could suppress excessive inflammation has been crucial to fight against chronic inflammatory and autoimmune disorders. Immunomodulatory agents regulate the function of immune system cells to manage their activities. Current therapy regimens for the inflammatory and autoimmune disorders rely on immunomodulatory drug molecules but they are also associated with unwanted and severe side effects. In order to prevent the side effects associated with drug molecules, the field should generate novel immunomodulatory drug candidates and further test them. Moreover, the generation of photodynamic immunomodulatory molecules would also decrease possible side effects. Photodynamic activation enables specific and localized activation of the active ingredients upon exposure to a certain wavelength of light. In our study, we generated copper-based chalcogenide structures in gel and nanoparticle form by using a water-based method so that they are more biocompatible.After their chemical characterization, they were tested on mammalian macrophages in vitro. Our results suggest that these molecules were anti-inflammatory in dark conditions and their anti-inflammatory potentials significantly increased upon xenon light treatment. We are presenting novel photodynamic immunomodulatory agents that can be used to suppress excessive inflammation in disease conditions that have been associated with excessive inflammation.

Imidazole substituted Zinc(II) phthalocyanines for co-catalyst-free photoelectrochemical and photocatalytic hydrogen evolution: influence of the anchoring group.

Novel zinc phthalocyanine derivatives, ZnPc-1 and ZnPc-2, consisting of one and four imidazole units, respectively, have been synthesized and utilized as panchromatic photosensitizers for photocatalytic and photoelectrochemical H2 evolution. The effect of the imidazole-anchoring group on the photocatalytic H2 production has been compared with ZnPc-3, which possesses a carboxylic acid unit as the anchoring group. ZnPc-1/TiO2 shows the best photoactivity with the highest H2 evolution rate of 0.4006 mmol g-1 h-1, which is much higher than that of ZnPc-2/TiO2 and ZnPc-3/TiO2 (0.3319 mmol g-1 h-1 and 0.3555 mmol g-1 h-1, respectively). After 20 h of irradiation, ZnPc-1 produces an H2 production rate of 3.4187 mmol g-1 with a turnover number (TON) of 14863 and a solar-to-hydrogen energy (STH) conversion efficiency of 1.03%, without using a co-catalyst.

Development of a Novel Nanoarchitecture of the Robust Photosystem I from a Volcanic Microalga Cyanidioschyzon merolae on Single Layer Graphene for Improved Photocurrent Generation.

Here, we report the development of a novel photoactive biomolecular nanoarchitecture based on the genetically engineered extremophilic photosystem I (PSI) biophotocatalyst interfaced with a single layer graphene via pyrene-nitrilotriacetic acid self-assembled monolayer (SAM). For the oriented and stable immobilization of the PSI biophotocatalyst, an His6-tag was genetically engineered at the N-terminus of the stromal PsaD subunit of PSI, allowing for the preferential binding of this photoactive complex with its reducing side towards the graphene monolayer. This approach yielded a novel robust and ordered nanoarchitecture designed to generate an efficient direct electron transfer pathway between graphene, the metal redox center in the organic SAM and the photo-oxidized PSI biocatalyst. The nanosystem yielded an overall current output of 16.5 µA·cm-2 for the nickel- and 17.3 µA·cm-2 for the cobalt-based nanoassemblies, and was stable for at least 1 h of continuous standard illumination. The novel green nanosystem described in this work carries the high potential for future applications due to its robustness, highly ordered and simple architecture characterized by the high biophotocatalyst loading as well as simplicity of manufacturing.

Investigation of the antifouling properties of polyethersulfone ultrafiltration membranes by blending of boron nitride quantum dots.

This study aims to investigate the modification of polyethersulfone (PES) membrane with boron nitride quantum dots (BNQD) for improving the antifouling performance. The composite membranes were synthesized by blending different amounts of BNQD (0.50, 1.00, and 2.00 wt.%) into PES with the non-solvent induced phase separation (NIPS) method. UV-vis absorption, X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize BNQD. Moreover, porosity, pore size, contact angle, permeability, bovine serum albumin (BSA) rejection, and antifouling properties were determined for composite membranes. The enhanced biological activity of BNQD was investigated based on antioxidant, antimicrobial, anti-biofilm, bacterial viability inhibition, and DNA cleavage studies. The BNQD showed 19.35 % DPPH radical scavenging activity and 76.45 % ferrous ion chelating activity at 500 mg/L. They also exhibited good chemical nuclease activity at all concentrations. BNQD had moderate antibacterial activity against all tested microorganisms. Biofilm inhibition percentage of BNQD was determined as 82.31 % at 500 mg/L. Cell viability assay demonstrated that the BNQD showed strong cell viability inhibition 99.9 % at the concentration of 1000 mg/L. The porosity increased from 56.83 ± 1.17%-61.83 ± 1.17 % while BNQD concentration increased from 0 to 2.00 wt%. Moreover, the hydrophilicity of BNQD nanocomposite membranes also increased from 75.42 ± 0.56° to 65.34 ± 0.25°. The mean pore radius is far slightly changed from 16.47 ± 0.35 nm to 19.16 ± 0.22 nm. The water flux increased from 133.5 ± 9.5 L/m2/h (for pristine membrane) to 388.6 ± 18.8 L/m2/h (for PES/BNQD 2.00 wt% membrane). BSA flux increased from 38.8 ± 0.9 L/m2/h to 63.2 ± 2.7 L/m2/h up to 1.00 wt% amount of BNQD nanoparticles.

Enhancement of direct electron transfer in graphene bioelectrodes containing novel cytochrome c553 variants with optimized heme orientation.

The highly efficient bioelectrodes based on single layer graphene (SLG) functionalized with pyrene self-assembled monolayer and novel cytochromec553(cytc553)peptide linker variants were rationally designed to optimize the direct electron transfer (DET) between SLG and the heme group of cyt. Through a combination of photoelectrochemical and quantum mechanical (QM/MM) approaches we show that the specific amino acid sequence of a short peptide genetically inserted between the cytc553holoprotein and thesurface anchoring C-terminal His6-tag plays a crucial role in ensuring the optimal orientation and distance of the heme group with respect to the SLG surface. Consequently, efficient DET occurring between graphene and cyt c553 leads to a 20-fold enhancement of the cathodic photocurrent output compared to the previously reported devices of a similar type. The QM/MM modeling implies that a perpendicular or parallel orientation of the heme group with respect to the SLG surface is detrimental to DET, whereas the tilted orientation favors the cathodic photocurrent generation. Our work confirms the possibility of fine-tuning the electronic communication within complex bio-organic nanoarchitectures and interfaces due to optimization of the tilt angle of the heme group, its distance from the SLG surface and optimal HOMO/LUMO levels of the interacting redox centers.

Detection of Kallikrein-Related Peptidase 4 with a Label-free Electrochemical Impedance Biosensor Based on a Zinc(II) Phthalocyanine Tetracarboxylic Acid-Functionalized Disposable Indium Tin Oxide Electrode.

A new impedimetric biosensing system based on kallikrein-related peptidase 4 (KLK 4) antigen-specific antibodies and a zinc(II) phthalocyanine tetracarboxylic acid (Zn-PcTCa) matrix material was developed for the first time in this study. First, a Zn-PcTCa-coated indium tin oxide surface was used as an interface matrix material for the immobilization of anti-KLK 4 antibodies, and they bound to the platform via amide bonds. In the presence of KLK 4 antigens, the anti-KLK 4 antibodies specifically captured these antigens and caused changes in the electrochemical properties of the system. Randles equivalent circuit was utilized to evaluate the impedimetric signal, which was measured with the help of an electrochemical impedance spectroscopy method. After the specific interaction, the electron transfer resistance (Rct) was remarkably increased and displayed a linear relationship with the level of the KLK 4 antigen in the range of 0.02-15 pg/mL, with a a detection limit of 6.8 fg/mL. The designed biosensor was able to detect a KLK 4 antigen with good sensitivity, excellent specificity, and high stability. In addition, because of having a low-cost and robust procedure for fabrication, it could be repeatedly used in several areas including clinical diagnosis.

Experimental confirmation of antimicrobial effects of GdYVO4:Eu3+ nanoparticles.

Nanotechnology can be applied to design antibacterial agents to combat antibiotic resistance. The aim of the present study was to assess the antimicrobial effects and cytotoxicity of GdYVO4:Eu3+ nanoparticles (NPs). Biofilm inhibition activity, antimicrobial activity, bacterial viability inhibition and DNA cleavage activity of GdYVO4:Eu3+ NPs were studied. In addition, the impact of GdYVO4:Eu3+ NPs on the mitochondrial membrane potential (ΔΨM) of host immune cells and, hence, their apoptosis was analyzed by JC-1 staining using flow cytometry. GdYVO4:Eu3+ NPs demonstrated good antimicrobial, cell viability inhibition and DNA cleavage activities. In addition, GdYVO4:Eu3+ NPs showed good biofilm inhibition activity against S. aureus and P. aeruginosa and inhibition percentages were 89.15% and 79.54%, respectively. However, GdYVO4:Eu3+ NPs promoted mitochondrial depolarization and apoptosis of leukocytes at high concentrations. GdYVO4:Eu3+ nanoparticles are promising antibacterial agents. However, more efforts should be exerted to ensure their safety.

Molecular mechanism of direct electron transfer in the robust cytochrome-functionalised graphene nanosystem.

Construction of green nanodevices characterised by excellent long-term performance remains high priority in biotechnology and medicine. Tight electronic coupling of proteins to electrodes is essential for efficient direct electron transfer (DET) across the bio-organic interface. Rational modulation of this coupling depends on in-depth understanding of the intricate properties of interfacial DET. Here, we dissect the molecular mechanism of DET in a hybrid nanodevice in which a model electroactive protein, cytochrome c 553 (cyt c 553), naturally interacting with photosystem I, was interfaced with single layer graphene (SLG) via the conductive self-assembled monolayer (SAM) formed by pyrene-nitrilotriacetic acid (pyr-NTA) molecules chelated to transition metal redox centers. We demonstrate that efficient DET occurs between graphene and cyt c 553 whose kinetics and directionality depends on the metal incorporated into the bio-organic interface: Co enhances the cathodic current from SLG to haem, whereas Ni exerts the opposite effect. QM/MM simulations yield the mechanistic model of interfacial DET based on either tunnelling or hopping of electrons between graphene, pyr-NTA-M2+ SAM and cyt c 553 depending on the metal in SAM. Considerably different electronic configurations were identified for the interfacial metal redox centers: a closed-shell system for Ni and a radical system for the Co with altered occupancy of HOMO/LUMO levels. The feasibility of fine-tuning the electronic properties of the bio-molecular SAM upon incorporation of various metal centers paves the way for the rational design of the optimal molecular interface between abiotic and biotic components of the viable green hybrid devices, e.g. solar cells, optoelectronic nanosystems and solar-to-fuel assemblies.

Antiinflammatory photodynamic therapy potential of polyoxyethylene-substituted perylene diimide, nitrocatechol, and azo dye.

Photodynamic therapy (PDT) applications enable light-controlled activation of drug candidates instead of their constitutive activities to prevent undesired side effects associated with their constant activities. A specific wavelength of light is utilized to enable electron mobility in the chemical structure, which results in differential activities that may alter cell viability and cellular functions. Canonical photodynamic therapy applications mostly focus on cytotoxicity-based antimicrobial and anticancer properties of the PDT agents. In this study, we focused on subtoxic concentrations of three different molecules containing polyoxyethylene group and examined their antiinflammatory activities on stimulated mammalian macrophages. Stimulated macrophages produce proinflammatory cytokines TNF and IL6. In the presence of a light source, our PDT agents were activated for 5 and 10 min during their application to the macrophages. Based on the ELISA results, the compounds had anti-inflammatory PDT activities. Trypan blue staining results suggest that these derivatives exerted their activities without leading to cytotoxicity. Our results suggest noncanonical PDT applications of these derivatives that can alter cellular activities without leading to cell death.

Immunoactive photosensitizers had photodynamic immunostimulatory and immunomodulatory effects on mammalian macrophages.

Photodynamic compounds have great potential in biological applications. Their controlled and localized activation with specific wavelength of light provides opportunities to potentially evade the side effects of today's cancer therapies. Biologically compatible photosensitizers can be used in therapy against cancer, infections as well as inflammatory and immune disorders. In this study, we examined chlorophyll derivatives for anti-microbial, immunostimulatory and immunomodulatory activities. Under dark conditions, these chlorophyll derivatives had strong anti-microbial activities on gram positive S.aureus and gram negative E.coli. Photo activation of the chlorophyll derivatives did not alter their anti-microbial activities on gram negative or gram positive bacteria. In order to examine how these anti-microbial chlorophyll derivatives might effect immune reaction of macrophages, they were tested on mammalian macrophages. They had immunostimulatory activities on them in the dark conditions since they led to increased TNF and IL6 cytokine production even in the absence of stimulants lipopolysaccharide (LPS) and lipoteichoic acid (LTA). Photo-activation of the compounds led to decrease in pro-inflammatory cytokines, TNF and IL6, production by LPS or LTA activated macrophages. Therefore, these molecules can be used to regulate the immune response in the patients with bacterial infection while leading to death of bacteria. Light induced activation of the compounds could enable localized and controlled activation of their anti-inflammatory effects.

Subphthalocyanine-sensitized TiO2 photocatalyst for photoelectrochemical and photocatalytic hydrogen evolution.

A series of SubPcs comprising a carboxylic acid anchoring group at the peripheral (SubPcs 1, 2) or axial position (SubPc 3) were synthesized and used as sensitizers for photocatalytic H2 production, for the first time. SubPc 3/TiO2 shows the best photocatalytic activity with a hydrogen evolution rate of 1396 µmol h-1, which is much higher than that of SubPcs 1 and 2 (771 and 658 µmol g-1, respectively). This work clearly shows that considering their optical and redox properties, SubPcs are promising candidates for light-driven water splitting systems.