Axially paraben substituted silicon(IV) phthalocyanines towards dental pathogen Streptococcus mutans: Synthesis, photophysical, photochemical and in vitro properties

Effect of Axial Ligand Length on Biological and Anticancer Properties of Axially Disubstituted Silicon Phthalocyanines

In this study, three new axially disubstituted silicon phthalocyanines (SiPc1-3) and their quaternized phthalocyanine derivatives (QSiPc1-3) were prepared and characterized. The biological properties (antioxidant, antimicrobial, antibiofilm, and microbial cell viability activities) of the water-soluble silicon phthalocyanines were examined, as well. A 1 % DMSO diluted with pure water was used as a solvent in biological activity studies. All the compounds exhibited high antioxidant activity. They displayed efficient antimicrobial and antimicrobial photodynamic therapeutic properties against various microorganisms, especially Gram (+) bacteria. Additionally, they demonstrated high antibiofilm activities against S. aureus and P. aeruginosa. In addition, 100 % bacterial reduction was obtained for all the studied phthalocyanines against E. coli viable cells. Besides, the DNA cleavage and binding features of compounds (QSiPc1-3) were studied using pBR322 DNA and CT-DNA, respectively. Furthermore, the human topoisomerase I enzyme inhibition activities of compounds QSiPc1-3 were studied. Anticancer properties of the water-soluble compounds were investigated using cell proliferation MTT assay. They exhibited anticarcinogenic activity against the human colon cancer cell line (DLD-1). Compounds QSiPc1 and QSiPc3 displayed a high anticarcinogenic effect on the DLD-1 cell line. The obtained results indicated that all the studied compounds may be effective biological agents and anticancer drugs after further investigations.

Photodynamic inactivation of pathogenic Gram-negative and Gram-positive bacteria mediated by Si(IV) phthalocyanines bearing axial ammonium units

The photodynamic inactivation (PDI) of microorganisms has gained interest as an efficient option for conventional antibiotic treatments. Recently, Si(IV) phthalocyanines (SiPcs) have been highlighted as promising photosensitizers (PSs) to the PDI of microorganisms due to their remarkable absorption and emission features. To increase the potential of cationic SiPcs as PS drugs, one novel (1a) and two previously described (2a and 3a) axially substituted PSs with di-, tetra-, and hexa-ammonium units, respectively, were synthesized and characterized. Their PDI effect was evaluated for the first time against Escherichia coli and Staphylococcus aureus, a Gram-negative and a Gram-positive bacterium, respectively. The photodynamic treatments were conducted with PS concentrations of 3.0 and 6.0 μM under 60 min of white light irradiation (150 mW.cm^-2). The biological results show high photodynamic efficiency for di- and tetra-cationic PSs 1a and 2a (6.0 μM), reducing the E. coli viability in 5.2 and 3.9 log, respectively (after 15 min of dark incubation before irradiation). For PS 3a, a similar bacterial reduction (3.6 log) was achieved but only with an extended dark incubation period (30 min). Under the same experimental conditions, the photodynamic effect of cationic PSs 1a-3a on S. aureus was even more promising, with abundance reductions of ca. 8.0 log after 45-60 min of PDI treatment. These results reveal the high PDI efficiency of PSs bearing ammonium groups and suggest their promising application as a broad-spectrum antimicrobial to control infections caused by Gram-negative and Gram-positive bacteria.

Chemo-photodynamic Activity of Silicon Phthalocyanines Bearing Cyclooxygenase Inhibitors on Colorectal Cancer Cell Lines

Colorectal cancer ranks as the third most lethal cancer worldwide, resulting in over 1 million cases and 900 000 deaths per year. According to population-based studies, administration of long-term non-steroidal anti-inflammatory drugs (NSAIDs) was proven to reduce the risk of a subject developing colorectal cancer. In the present study, the anti-cancer activity of two different NSAIDs, sulindac- (Pc-1) or diclofenac-substituted (Pc-2) asymmetric silicon phthalocyanine derivatives, was evaluated in four different colorectal cancer cell lines bearing various carcinogenic mutations. In this context, the IC₅₀ values of each compound after 24 and 48 h were determined on HCT116, SW480, LoVo, and HT29 cell lines, and the effects of the compounds on programmed cell death pathways apoptosis and autophagy, their impact on cell cycle progression, and the effect of NSAID moieties they bear on COX-1 and COX-2 proteins were analyzed. In addition, the photophysical and photochemical properties of a synthesized Pc derivative bearing axial diclofenac and triethylene glycol groups (Pc-2) have been investigated, and the compound has been characterized by using different analytical techniques. Our results indicated that both compounds inhibit COX protein expression levels, activate apoptosis in all cell lines, and lead to cell cycle arrest in the G2/M phase, depending on the COX expression profiles of the cell lines, indicating that NSAIDs can be coupled with Pc's to achieve increased anti-cancer activity, especially on cancer cells known to have high COX activity.

Novel axially symmetric and unsymmetric silicon(IV) phthalocyanines having anti-inflammatory groups: synthesis, characterization and their biological properties

New asymmetric Si(IV)Pc (1), monomeloxicammonotriethyleneglycolmonomethylether (phthalocyaninano)silicone, axially ligated with meloxicam as a non-steroidal anti-inflammatory drug (NSAID), or triethylene glycol monomethyl ether and symmetric Si(IV)Pc (2), diclofenac(phthalocyaninano)silicone, axially ligated with two diclofenac as NSAID, were synthesized and characterized as antioxidant and antimicrobial agents together with polyoxo-SiPc (3), ditriethyleneglycolmonomethylether(phthalocyaninano)silicone, and SiPc(OH)₂ (4), dihydroxy(phthalocyaninano)silicone. The photophysical and photochemical properties of these compounds were investigated. Then, antioxidant assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferrous ion chelating activities, were performed for these Si(IV) phthalocyanine derivatives (1, 2, 3 and 4). The highest DPPH scavenging activity of 73.48% was achieved with compound 2 and the highest ferrous chelating ability of 66.42% was obtained with compound 3. The results of the antioxidant assays indicated that Pc derivatives 1, 2 and 3 have remarkable superoxide radical scavenging activities, and moderate 2,2-diphenyl-1-picrylhydrazyl activities and metal chelating activities. The antimicrobial effects of the Si(IV) phthalocyanine compounds were studied against six pathogenic bacteria and two pathogenic microfungi. The results for the antimicrobial activity of these compounds indicated that Enterococcus faecalis (ATCC 29212) was the most sensitive microorganism and Pseudomonas aeruginosa (ATCC 27853) and Legionella pneumophila subsp. pneumophila (ATCC 33152) were the most resistant microorganisms against the tested compounds. The DNA cleavage ability and microbial cell viability of these compounds were studied. The studied compounds demonstrated excellent DNA nuclease activity and exhibited 100% cell viability inhibition at 500 mg L^-1. Also, the antimicrobial photodynamic therapy of the compounds was tested against Escherichia coli (ATCC 25922) and significant photodynamic antimicrobial activity was observed. In addition, the effect of phthalocyanines on biofilm inhibition produced by Staphylococcus aureus (ATCC 25923) was also tested and 3 showed excellent biofilm inhibition of 82.14%.

Pharmaceutical Nanotechnology Applied to Phthalocyanines for the Promotion of the Antimicrobial Photodynamic Therapy: A Literature Review

Phthalocyanines are photosensitizers activated by light at a specific wavelength in the presence of oxygen and act topically through the production of Reactive Oxygen Species, which simultaneously attack several biomolecular targets in the pathogen agent and, therefore, have multiple and variable action sites. This nonspecific action site delineates the conventional resistance mechanisms. Antimicrobial Photodynamic Therapy (aPDT) is safe, easy to implement and, unlike conventional agents, the activity spectrum of photoantimicrobials. This work is a systematic review of the literature based on nanocarriers containing phthalocyanines in aPDT against bacteria, fungi, viruses, and protozoa. The search was performed in two different databases (MEDLINE/PubMed and Web of Science) between 2011 and May 2021. Nanocarriers often improve the action or are equivalent to free drugs, but their use allows substituting the organic solvent in the case of hydrophobic phthalocyanines, allowing for a safer application of aPDT with the possibility of prolonged release. In the case of hydrophilic phthalocyanines, they would allow for nonspecific site delivery with a possibility of cellular internalization. A single infectious lesion can have multiple microorganisms, and PDT with phthalocyanines is an interesting treatment given its ample spectrum of action. It is possible to highlight the upconversion nanosystems, which allow for the activation of phthalocyanine in deeper tissues by using longer wavelengths, as a system that has not yet been studied, but which could provide treatment solutions. The use of nanocarriers containing phthalocyanines requires more studies in animal models and clinical studies to establish the use of aPDT in humans.

Photophysicochemical and Biological Properties of New Phthalocyanines Bearing 4-(trifluoromethoxy)phenoxy and 2-(4-methylthiazol-5-yl)ethoxy Groups on Peripheral Positions

As thiazoles and fluorinated groups are well known as active species of hybrid pharmaceutical agents, this study aimed to evaluate the synergic effect of these groups on the biological features of phthalocyanines for the first time in the hope of discovering efficient pharmaceutical agents. Therefore, a new phthalonitrile derivative namely 4-(2-(4-methylthiazol-5-yl)ethoxy)-5-(4-(trifluoromethoxy)phenoxy)phthalonitrile (1) and its metal-free (2)/metal phthalocyanines (3-5) were prepared and characterized using various spectroscopic techniques. Solubility of new phthalocyanines (2-5) was examined in a series of polar and nonpolar solvents. Additionally, sono/photochemical methods were applied to examine the photophysical and sono/photochemical properties of new zinc phthalocyanine to measure its potential as a probable material for sono/photodynamic therapies. The antioxidant activities of compounds (1-5) were evaluated using the DPPH scavenging activity method and the highest radical scavenging activity was obtained 92.13% (200 mg L^-1 ) for manganese phthalocyanine. All the phthalocyanines demonstrated high DNA nuclease activity, as well. The antimicrobial activities of compounds (1-5) were investigated using disk diffusion and microdilution methods. The phthalocyanines exhibited effective microbial cell inhibition activity against Escherichia coli (E. coli). Antimicrobial photodynamic therapy activity was investigated against E. coli by LED irradiation. Compounds (2-5) acted as photosynthesizers. Also, they displayed significant biofilm inhibition activity against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa).

Nipagin-Functionalized Porphyrazine and Phthalocyanine-Synthesis, Physicochemical Characterization and Toxicity Study after Deposition on Titanium Dioxide Nanoparticles P25

Aza-porphyrinoids exhibit distinct spectral properties in UV-Vis, and they are studied in applications such as photosensitizers in medicine and catalysts in technology. The use of appropriate peripheral substituents allows the modulation of their physicochemical properties. Phthalocyanine and sulfanyl porphyrazine octa-substituted with 4-(butoxycarbonyl)phenyloxy moieties were synthesized and characterized using UV-Vis and NMR spectroscopy, as well as mass spectrometry. A comparison of porphyrazine with phthalocyanine aza-porphyrinoids revealed that phthalocyanine macrocycle exhibits higher singlet oxygen generation quantum yields, reaching the value of 0.29 in DMF. After both macrocycles had been deposited on titanium dioxide nanoparticles P25, the cytotoxicities and photocytotoxicities of the prepared materials were studied using a Microtox® acute toxicity test. The highest cytotoxicity occurred after irradiation with a red light for the material composed of phthalocyanine deposited on titania nanoparticles.

Turning Photons into Drugs: Phthalocyanine-Based Photosensitizers as Efficient Photoantimicrobials

One of the most promising alternatives for treating bacterial infections is antimicrobial photodynamic therapy (aPDT), making the synthesis and application of new photoactive compounds called photosensitizers (PS) a dynamic research field. In this regard, phthalocyanine (Pc) derivatives offer great opportunities due to their extraordinary light-harvesting and tunable electronic properties, structural versatility, and stability. This Review, rather than focusing on synthetic strategies, intends to overview current progress in the structural design strategies for Pcs that could achieve effective photoinactivation of microorganisms. In addition, the Review provides a concise look into the recent developments and applications of nanocarrier-based Pc delivery systems.

Synthesis of axially disubstituted silicon phthalocyanines and investigation of their in vitro cytotoxic/phototoxic anticancer activities

In this study, two SiPcs have been selected and the photodynamic therapy potentials were evaluated of the Pcs. Synthesis of Axially 2-decyn-1-oxy disubstituted Es-SiPc-2 was newly synthesized by the reaction of SiPcCl2 with 2-decyn-1-ol in the presence of NaH in toluene. Furthermore, their nuclear imaging potentials were evaluated in human colon adenocarcinoma (HT-29) and human lung fibroblast cell (WI-38) cell lines. The uptake results have indicated that Es-SiPc labeled with [Formula: see text]I radionuclide ([Formula: see text]I-Es-SiPc) was approximately 2-fold higher in the HT-29 cell line than the WI-38 cell line. In other words, the target/non-target tissue ratio is defined as two in the HT-29/WI-38 cell lines. Besides, the uptake values of [Formula: see text]I-Es-SiPc were found to be higher than [Formula: see text]I-Es-SiPc-2. [Formula: see text]I-Es-SiPc and [Formula: see text]I-Es-SiPc-2 are promising for imaging or treating colon adenocarcinoma. In vitrophotodynamic therapy (PDT) studies have shown that both compounds are suitable and can be used in this field. Also, Es-SiPc has been shown to have higher phototoxicity than Es-SiPc-2.

The improved antibacterial efficiency of a zinc phthalocyanine when embedded on silver nanoparticle modified silica nanofibers

This work reports on the fabrication and modification of electrospun polymer free silica nanofibers (SiO₂ NFs) with the aim of creating heterogeneous antibacterial catalysts. The optical and photophysical properties of the obtained NFs i.e. bare SiO₂, Ag-SiO₂, Pc-SiO₂ and Pc@Ag-SiO₂ NFs (Pc = phthalocyanine) were compared and reported. The singlet oxygen quantum yields of the Pc-SiO₂ and Pc@Ag-SiO₂ NFs were also quantified and found to be 0.08 and 0.12, respectively, in water. All the modified SiO₂ NFs were found to possess photoactivity against S. aureus with the most effective being the Pc@Ag-SiO₂ NFs due to the synergy between the Pc and Ag nanoparticles. The bare SiO₂ NFs do not exhibit any antibacterial activity while the Ag-SiO₂ and Pc@Ag-SiO₂ NFs were found to also exhibit dark toxicity. The generated photocatalysts are attractive because they are active against bacteria and they are easily retrievable post-application. The nanocatalysts reported herein are therefore feasible candidates for real-life antibacterial applications.

Photodynamic therapy effect of morpholinium containing silicon (IV) phthalocyanine on HCT-116 cells

In this study, we investigated the in vitro potential of axially 1-morpholiniumpropan-2-ol disubstituted silicon (IV) phthalocyanine (SiPc) which was synthesized previously, on HCT-116 cells as a photodynamic therapy (PDT) agent. The singlet oxygen and photodegradation quantum yields of SiPc were calculated using UV-vis spectrophotometer. The cytotoxic and phototoxic effects of SiPc were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Annexin V-FITC/PI double staining kit, cell cycle kit, and mitochondria membrane potential (ΔΨm) assay kit with JC-1 were used to indicate the cell death pathway. Caspase-3 and β-catenin protein expressions were evaluated by western blotting. The singlet oxygen and photodegradation quantum yields of SiPc were calculated as 0.73 and 3.64 × 10^-4 in DMSO. The cell viability assays showed that IC₅₀ value of SiPc did not reach to 100 μM without irradiation. However, excellent phototoxicity was observed in the presence of SiPc upon light irradiation. The cells undergoing early/late apoptosis significantly increased in the presence SiPc at 5 μM upon light irradiation. Besides, the proportion of cells at S and G2/M phase increased. Moreover, mitochondria membrane potentials significantly decreased at 1 and 5 μM of SiPc with light irradiation. While caspase-3 expression increased, β-catenin expression significantly decreased on HCT-116 in the presence of SiPc (p < 0.01). The results indicated that the PDT could be related to apoptosis and Wnt/β-catenin signaling pathway. Based on our findings, SiPc exhibited a significant PDT effect on HCT-116 cells therefore, worthy of more detailed study.

Impact of water-soluble zwitterionic Zn(II) phthalocyanines against pathogenic bacteria

The photodynamic impact of water-soluble zwitterionic zinc phthalocyanines (ZnPc1-4) was studied on pathogenic bacterial strains after specific light exposure (LED 665 nm). The structural differences between the studied ZnPc1-4 are in the positions and the numbers of substitution groups as well as in the bridging atoms (sulfur or oxygen) between substituents and macrocycle. The three peripherally substituted compounds (ZnPc1-3) are tetra-2-(N-propanesulfonic acid)oxypyridine (ZnPc1), tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc2), and octa-substituted 2-(N-propanesulfonic acid)mercaptopyridine (ZnPc3). The nonperipherally substituted compound is tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc4). The uptake and localization capability are studied on Gram (+) Enterococcus faecalis and Gram (-) Pseudomonas aeruginosa as suspensions and as 48 h biofilms. Relatively high accumulations of ZnPc1-4 show bacteria in suspensions with different cell density. The compounds have complete penetration in E. faecalis biofilms but with nonhomogenous distribution in P. aeruginosa biomass. The cytotoxicity test (Balb/c 3T3 Neutral Red Uptake) with ZnPc1-4 suggests the lack of dark toxicity on normal cells. However, only ZnPc3 has a minimal photocytotoxic effect toward Balb/c 3T3 cells and a comparable high potential in the photoinactivation of pathogenic bacterial species.

Biodegradation of methyl and butylparaben by bacterial strains isolated from amended and non-amended agricultural soil. Identification, behavior and enzyme activities of microorganisms

The aim of the present study was to investigate the kinetics of methylparaben (MPB) and butylparaben (BPB) removal, two emerging pollutants with possible endocrine disrupting effects, from agricultural soil with and without amendment with compost from sewage sludge used as biostimulant. Compound removal is explained by a first-order kinetic model with half-life times of 6.5/6.7 days and 11.4/8.2 days, in presence/absence of compost, for MPB and BPB respectively. % R² for the fitted model were higher than 96% in all cases. Additionally, isolation of bacteria capable to grow using MPB or BPB as carbon source was also carry out. Laboratory tests demonstrated the ability of these bacteria to biodegrade MPB and BPB from culture media in more than 95% in some cases. These strains showed high ability to biodegrade the compounds. Ten isolates, most of them related to Gram positive bacteria of the genus Bacillus, were identified by 16S rRNA gene sequencing. The study of the enzymatic activities of the isolates revealed both esterase (C4) and esterase-lipase activities.

Novel carboxylic acid terminated silicon(IV) and zinc(II) phthalocyanine photosensitizers: Synthesis, photophysical and photochemical studies

In order to improve the efficacy of photochemical properties for photodynamic therapy (PDT) applications, carboxylic acid groups axially conjugated with silicon(IV) and at the peripheral position with zinc(II) phthalocyanine skeletons for new photosensitizers to investigate the influence of the COOH group positions on the photophysicochemical performance are described in this study. Silicon (IV) (3 and 5) and zinc (II) (7) phthalocyanines were characterized by UV-vis, FTIR, 1H-NMR, MALDI-TOF MS and elemental analysis spectral data. Furthermore, the photophysical (fluorescence quantum yields and fluorescence quenching studies), photochemical (photodegradation and singlet oxygen generation) and aggregation properties of the newly synthesized phthalocyanines were investigated in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solutions. The results were compared with that of zinc and silicon phthalocyanines. Singlet oxygen quantum yields ranged from 0.23 to 0.63 via Type II mechanism under the experimental conditions studied. The fluorescence of the phthalocyanine complexes (3, 5 and 7) is effectively quenched by 1,4-benzoquinone (BQ) in DMSO, DMF and THF.

Five-nuclear phthalocyanine complex bearing terpyridine zinc complex: Synthesis, and photophysicochemical studies

The context of this study is based on the synthesis of tetrakis{4-(2-([2,2[Formula: see text]:6[Formula: see text],2[Formula: see text]-terpyridine]Zn(II)-4[Formula: see text]-yl(methyl)amino)ethoxy)}phthalocyaninato zinc (II) (3) bearing four terpyridine-Zn(II) complexes that are directly linked through oxygen bridges to the macrocyclic core in order to create new supramolecular assemblies. The target phthalocyanine (3) was obtained by cyclotetramerization reaction of terpyridine-Zn (II) complex substituted phthalonitrile (2). All novel compounds synthesized in this study were fully characterized by general spectroscopic techniques such as FT-IR, UV-vis, and [Formula: see text]H-NMR, [Formula: see text]C-NMR, elemental analysis and mass spectroscopy. Spectral, photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen production and photodegradation under light irradiation) properties of newly synthesized phthalonitrile (2) and its phthalocyanine derivative (3) as five nuclear phthalocyanine were investigated in DMSO solutions.

Axially Decorated SiIV -phthalocyanines Bearing Mannose- or Ammonium-conjugated Siloxanes: Comparative Bacterial Labeling and Photodynamic Inactivation<sup/>

Herein, we present a comparative study about the photoinactivation of Staphylococcus aureus (Gram-positive model) and Escherichia coli (Gram-negative model) employing a neutral and a dicationic axially functionalized Si^IV -phthalocyanine. Depending on the charge of the siloxane moiety (neutral monosaccharide or cationic ammonium salt), different interactions with the bacteria were observed, and a differential photoinactivation was facilitated. The intensity of the fluorescence labeling correlated with the photoinactivation of the two types of bacteria: While the neutral species only significantly affected the Gram-positive cells, we observed that the positively charged photosensitizer interacted both with the Gram-positive and with the Gram-negative models. The dicationic photosensitizer labeled both models with a characteristic deep-red fluorescence and photoinactivated both classes of prokaryotes. In general, our study clearly demonstrates that axially ammoniumsiloxane-functionalized Si(IV) phthalocyaninates constitute excellent photosensitizers due to their weak aggregation in aqueous environments. In particular, we also show that charge-based targeting with axial ammonium groups leads toward broad-spectrum Si^IV -phthalocyanines for photodynamic inactivation of bacteria.

Axially substituted silicon(IV) phthalocyanine and its quaternized derivative as photosensitizers towards tumor cells and bacterial pathogens

Axially di-(alpha,alpha-diphenyl-4-pyridylmethoxy) silicon(IV) phthalocyanine (3) and its quaternized derivative (3Q) were synthesized and tested as photosensitizers against tumor and bacterial cells. These new phthalocyanines were characterized by elemental analysis, and different spectroscopic methods such as FT-IR, UV-Vis, MALDI-TOF and ¹H NMR. The photophysical properties such as absorption and fluorescence, and the photochemical properties such as singlet oxygen generation of both phthalocyanines were investigated in solutions. The obtained values were compared to the values obtained with unsubstituted silicon(IV) phthalocyanine dichloride (SiPcCl₂). The addition of two di-(alpha,alpha-diphenyl-4-pyridylmethanol) groups as axial ligands showed an improvement of the photophysical and photochemical properties and an increasement of the singlet oxygen quantum yield (Φ_Δ) from 0.15 to 0.33 was determined. The photodynamic efficacy of synthesized photosensitizers (3 and 3Q) were evaluated with promising photocytotoxicity (17% cell survival for 3 and 28% for 3Q) against the cervical cancer cell line (HeLa). The photodynamic inactivation of pathogenic bacterial strains Streptococcus mutans, Staphylococcus aureus, and Pseudomonas aeruginosa suggested a high susceptibility with quaternized derivative (3Q). The both Gram-positive bacterial strains were fully photoinactivated with 11μM 3Q and mild light dose 50J.cm^-2. In case of P. aeruginosa the effect was negligible for concentrations up to 22μM 3Q and light dose 100J.cm^-2. The results suggested that the novel axially substituted silicon(IV) phthalocyanines have promising characteristic as photosensitizer towards tumor cells. The quaternized derivative 3Q has high potential for photoinactivation of pathogenic bacterial species.

Synthesis, Photophysical and Photochemical Properties of a Set of Silicon Phthalocyanines Bearing Anti-Inflammatory Groups

In this study, a series of novel silicon (IV) phthalocyanines conjugated axially with anti-inflammatory (sulindac) and triethylene glycol groups has been synthesized. Different synthetic strategies were attempted to obtain the targeted molecules in high yield. The compounds were fully characterized by using different analyses techniques. Our objectives were to generate a system with sulindac group which enhances the singlet oxygen generation and exhibits anti-cancer effect. Therefore, photophysical and photochemical properties of these compounds were investigated in different solvents. The substituent effect on fluorescence quantum yield and singlet oxygen generation was evaluated for efficiency in photodynamic therapy (PDT) as photosensitizer. The molecules exhibited no aggregation tendency, solubility in common organic solvents, high singlet oxygen quantum yield and high photostability in DMSO so these favourable properties make them good candidates as photosensitizer for PDT. In addition, their stabilities were investigated in DMSO, THF, acetonitrile and DMF.

Antimicrobial graphene family materials: Progress, advances, hopes and fears

Graphene-based materials have become very popular bionanotechnological instruments in the last few years. Since 2010, the graphene family materials have been recognized as worthy of attention due to its antimicrobial properties. Functionalization of graphene (or rather graphene oxide) surface creates the possibilities to obtain efficient antimicrobial agents. In this review, progress and advances in this field in the last few years are described and discussed. Special attention is devoted to materials based on graphene oxide in which specifically selected components significantly modify biological activity of this carbon structure. Short introduction concerns the physicochemical properties of the graphene family materials. In the section on antimicrobial properties, proposed mechanisms of activity against microorganisms are given showing enhanced action of nanocomposites also under light irradiation (photoinduced activity). Another important feature, i.e. toxicity against eukaryotic cells, is presented with up-to-date data. Taking into account all the information on the properties of the described materials and usefulness of the graphene family as antimicrobial agents, hopes and fears concerning their application are discussed. Finally, some examples of promising usage in medicine and other fields, e.g. in phytobiology and water remediation, are shown.

New photosensitive nanometric graphite oxide composites as antimicrobial material with prolonged action

A new conjugate material based on partially reduced graphite oxide (rGO), silver nanoparticles (Ag), and bis(lysinato)zirconium(IV) phthalocyanine complex (ZrPc) was obtained. Its optical properties (absorption and photoluminescence) after dispersion in solvents were examined. The antimicrobial properties were tested to determine the effect of the composite on the following bacterial strains: Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, which are responsible for many infections and are one of the pathogens the most difficult to treatment. The results obtained for rGO-ZrPc-Ag composite were compared with the properties of GO, GO-ZrPc, and rGO-Ag structures. The influence of the near-infrared irradiation on the antimicrobial activity of ZrPc- and Ag-doped materials against bacteria was observed for very low concentration (0.32mg/mL) of GO-ZrPc to stop the growth of P. aeruginosa in comparison to the nonirradiated sample (41mg/mL). The usefulness of this material in therapy, such as wound infection treatment or endodontic treatment, as antibacterial agent with sustained action was discussed.