Biofilms formed by Candida albicans and the highly resistant Pichia kudriavzevii are critical virulence factors because of their resistance to conventional antifungals. This study explored antimicrobial photodynamic therapy (aPDT) using sulfonated polystyrene nanoparticles with an encapsulated tetraphenylporphyrin photosensitizer (TPP-NPs), synergistically enhanced by potassium iodide (KI), to combat biofilms of these yeasts. TPP-NPs irradiated by visible light generate antimicrobial singlet oxygen (O2(1Δg)), which oxidizes KI to form another reactive species (I2/I3 -), augmenting total antimicrobial effects. The usage of TPP-NPs led to reduced cell proliferation and biofilm viability in both species, with KI significantly enhancing efficacy and enabling lower TPP-NP doses. P. kudriavzevii biofilms were more susceptible (70-80% inhibition, up to 95% with KI) than C. albicans biofilms (30-40% inhibition), a crucial finding for drug-resistant P. kudriavzevii. This is the first demonstration that aPDT using TPP-NPs effectively reduces both biofilm formation and viability, especially against resistant P. kudriavzevii, highlighting its potential as a biocompatible alternative therapy for biofilm-associated infections.

Optical sensors based on the quenching of the luminescence of platinum(II)octaethylporphyrin (PtOEP) encapsulated in nanofiber polymeric membranes were prepared by electrospinning. The samples were characterized using scanning electron microscopy, confocal luminescence microscopy, absorption spectroscopy, and steady-state and time-resolved luminescence techniques. The properties of the sensors were changed by the selection of different polymeric membranes using polycaprolactone, polystyrene, polyurethane Tecophilic, and poly(vinylidene fluoride-co-hexafluoropropylene) polymers. Among them, biodegradable and biocompatible sensors prepared from polycaprolactone with a high oxygen diffusion coefficient exhibited a fast response time (0.37 s), recovery time (0.58 s), high sensitivity (maximum I 0 /I ratio = 52), reversible luminescent response, and linear Stern-Volmer quenching over the whole range of oxygen contents in both the gas atmosphere and aqueous media. Moreover, the proposed sensors exhibited high antibacterial properties, resulting in self-sterilization character of the membrane surface due to the photogeneration of singlet oxygen. This dual character can find application in the biomedical field, where both properties (oxygen sensing and self-sterilization) can be acquired from the same material.

New photoactive nanofiber materials based on an aminolyzed polycaprolactone membrane with demonstrated cytocompatibility were developed. Two photoactive compounds, the photosensitizer Rose Bengal and the nitric oxide photodonor 4-nitro-3-(trifluoromethyl)aniline, were covalently bonded to the nanofiber surface, with or without a glutaraldehyde linker. The surface functionalization was confirmed via X-ray photoelectron spectroscopy, UV-vis absorption, and steady-state and time-resolved luminescence spectroscopy. Upon excitation with green or blue light, these materials efficiently generate antibacterial species, including singlet oxygen, with a slight contribution of hydrogen peroxide and nitric oxide. A potent light-induced antibacterial effect was demonstrated against Escherichia coli. Furthermore, the functionalized photoactive membranes, especially those with a glutaraldehyde linker and photosterilized by light, not only excluded the material toxicity but also demonstrated improved cell adhesion and proliferation when tested with adipose tissue-derived stem cells. These materials, which offer a unique combination of light-controlled surface sterilization and high cellular compatibility, are promising for advanced tissue engineering applications.

New functionalities were added to biocompatible polycaprolactone nanofiber materials through the coencapsulation of chlorin e6 trimethyl ester (Ce6) photogenerating singlet oxygen and absorbing light both in the blue and red regions, and using 4-(N-(aminopropyl)-3-(trifluoromethyl)-4-nitrobenzenamine)-7-nitrobenzofurazan, NO-photodonor (NOP), absorbing light in the blue region of visible light. Time-resolved and steady-state luminescence, as well as absorption spectroscopy, were used to monitor both photoactive compounds. The nanofiber material exhibited photogeneration of antibacterial species, specifically nitric oxide and singlet oxygen, upon visible light excitation. This process resulted in the efficient photodynamic inactivation of E. coli not only close to nanofiber material surfaces due to short-lived singlet oxygen, but even at longer distances due to diffusion of longer-lived nitric oxide. Interestingly, nitric oxide was also formed by processes involving photosensitization of Ce6 during irradiation by red light. This is promising for numerous applications, especially in the biomedical field, where strictly local photogeneration of NO and its therapeutic benefits can be applied using excitation in the "human body phototherapeutic window" (600-850 nm). Generally, due to the high permeability of red light, the photogeneration of NO can be achieved in any aqueous environment where direct excitation of NOP to its absorbance in the blue region is limited.

Herein, we performed a simple virus capture and photoinactivation procedure using visible light on phosphatidylcholine vesicles. l-α-Phosphatidylcholine vesicles were enriched by viral receptors, GT1b gangliosides, and the nonpolar photosensitizer 5,10,15,20-tetraphenylporphyrin. These vesicles absorb in the blue region of visible light with a high quantum yield of antiviral singlet oxygen, O2 (1Δg). Through the successful incorporation of gangliosides into the structure of vesicles and the encapsulation of photosensitizers in their photoactive and monomeric state, the photogeneration of O2(1Δg) was achieved with high efficiency on demand; this process was triggered by light, and specifically targeting/inactivating viruses were captured on ganglioside receptors due to the short lifetime (3.3 μs) and diffusion pathway (approximately 100 nm) of O2(1Δg). Time-resolved and steady-state luminescence as well as absorption spectroscopy were used to monitor the photoactivity of the photosensitizer and the photogeneration of O2(1Δg) on the surface of the vesicles. The capture of model mouse polyomavirus and its inactivation were achieved using immunofluorescence methods, and loss of infectivity toward mouse fibroblast 3T6 cells was detected.

Signal denoising is a serious problem for in -situ laser diagnostics of gases dispersed in porous materials. An optical sensor system based on absorption spectroscopy of gases in a scattering environment was built using a 3D printed cell with reference samples of polystyrene foam. Selected A-band spectral lines of molecular oxygen were investigated using wavelength modulated spectroscopy with second harmonic detection. Quantitative information on the concentration of analyte dispersed in the porous medium was obtained at extremely low signal-to-noise ratio (SNR < 10). A spectral line shape fitting procedure based on the Gabor transform followed by a filtered inverse fast Fourier transform allowed to achieve a relatively high SNR with good linearity over a range of reduced oxygen concentrations in air. Finally, the applicability of the optical sensor system to monitor the diffusion of carbon dioxide into air dispersed in a Styrofoam sample and vice versa was successfully demonstrated.

Cantilever-enhanced Photoacoustic Spectroscopy in combination with Wavelength Modulation Spectroscopy was used for the multicomponent analysis of gases. Distributed feedback Quantum Cascade Laser tunable in the region of similar to 1045 - 1048 cm(-1) was used as the excitation source. Principal component analysis (PCA) and Partial Least Squares (PLS) (the pls package in the statistical software R) methods were applied to a mixture of selected substances (methanol and ethanol) in the gas phase to both simulated (www.spectraplot.com) and experimentally acquired spectra, PCA predicting the number of substances and PLS its concentrations.

We present a novel approach to creating nanofiber membranes with antibacterial, photocatalytic, and magnetic properties. Using electrospinning, we functionalized the membranes with tetraphenylporphyrin to produce singlet oxygen when exposed to visible light. We also added maghemite nanoparticles stabilized by polyethylenimine to enable remote manipulation of the membranes by a magnetic field. The resulting material demonstrated strong antibacterial effects against E. coli and improved photothermal properties upon short, 10-minute light irradiation, as well as the ability to produce hydrogen peroxide after irradiation. The magnetic properties of the membranes also make them suitable for use in hazardous or highly contaminated environments. These multifunctional nanofiber membranes have potential applications in fields such as biomedicine, environmental science, and industrial filtration.

Design of self-sterilizing materials for protecting surfaces from pathogenic microorganisms is of profound interest in the medical community. In this study, we have prepared textile materials composed of cotton fabrics and octahedral molybdenum cluster complex, [{Mo6I8}(DMSO)6](NO3)4 (DMSO – dimethyl sulfoxide), with photoactivated antibacterial, antifungal, and antiviral properties. These uniformly colored fabrics were prepared via the impregnation of cotton fabrics with solution of dissolved cluster complex. Strong bonding of cluster molecules to cotton provided high stability of the materials with negligible washing out during the washing with a laundry detergent. The obtained fabrics produced singlet oxygen at the surface upon light irradiation, and the production persisted after repeated irradiation cycles. The fabrics showed photoinduced antipathogenic activity against Gram-positive and Gram-negative bacteria, fungi, COVID-19 (SARS-CoV-2), and influenza B viruses.

Carbon quantum dots as a novel type of carbon nanomaterials have attracted the attention of many researchers because of their unique optical, antibacterial, and anticancer properties as well as their biocompatibility. In this study, for the first time, carbon quantum dots were prepared from o-phenylenediamine dissolved in toluene by a solvothermal route. Subsequently, the prepared carbon quantum dots were encapsulated into polyurethane films by a swelling–encapsulation–shrink method. Analyses of the results obtained by different characterization methods (AFM, TEM, EDS, FTIR, photoluminescence, and EPR) indicate the significant influence of the precursor on structural, chemical, and optical properties. Antibacterial and cytotoxicity tests showed that these dots did not have any antibacterial potential, because of the low extent of reactive oxygen species production, and showed low dark cytotoxicity. By investigating the cellular uptake, it was established that these dots penetrated the HeLa cells and could be used as probes for bioimaging.

We show that four cooperating Al atoms located at the two neighboring six-membered (6-MR) rings in the ferrierite framework can be readily discerned by luminescence studies. Thus, luminescent Zn(II) cations accommodated by one aluminum pair of the 6-MR ring can be effectively quenched by neighboring Co(II) ions stabilized by the second ring. Quenching occurs via the energy transfer mechanism and allows estimation of the critical radius of Zn(II)-Co(II) interactions. This points to the appropriate geometry and distance of the transition metal ions accommodated within zeolite, providing direct evidence of the four-aluminum atom arrangement in the ferrierite framework.

Neutral zirconocene complexes of the type [(eta(5)-C5Me5){eta(5)-C5H4CMe2P(=E)Ph-2}ZrCl2] (E = not present, O, S, or Se) with a cyclopentadienyl-attached phosphine and related phosphine oxide, sulfide, or selenide moiety were prepared and converted to their cationic counterparts by chloride abstraction with K[B(C6F5)(4)] to give compounds of the general formula [(eta(5)-C5Me5){eta(5)-C5H4CMe2P(=E)Ph-2-kappa E}ZrCl](+)[B(C6F5)(4)](-).Alter-natively, the chloride abstraction was accomplished by the reaction with ZnCl2 to give the same cationic species with a [Zn2Cl6](2-) counteranion. The ionic complexes, unlike the neutral counterparts, exhibited strongly enhanced luminescence properties originating in triplet ligand-to-metal ((LMCT)-L-3) excited states. Luminescence quantum yields up to 0.95 were determined in the solid state with luminescence lifetimes up to 50.6 mu s. In addition to structural characterization of the prepared complexes by X-ray diffraction methods, their electrochemistry was investigated by cyclic voltammetry, and their photophysical properties were studied with quantum-chemical calculations.

We prepared antibacterial polystyrene nanoparticles (NPs) with natural photosensitizers from chlorophyll (Chl) extract via a simple nanoprecipitation method using the same solvent for dissolution of the polystyrene matrix and extraction of Chls from spinach leaves. A high photo-oxidation and antibacterial effect was demonstrated on Escherichia coli and was based on the photogeneration of singlet oxygen O2(1Δg), which was directly monitored by NIR luminescence measurements and indirectly verified using a chemical trap. The photoactivity of NPs was triggered by visible light, with enhanced red absorption by Chls. To reduce the quenching effect of carotenoids (β-carotene, lutein, etc.) in the Chl extract, diluted and/or preirradiated samples, in which the photo-oxidized carotenoids lose their quenching effect, were used for preparation of the NPs. For enhanced photo-oxidation and antibacterial effects, a sulfonated polystyrene matrix was used for preparation of a stable dispersion of sulfonated NPs, with the quenching effect of carotenoids being suppressed.

We have prepared photoactive multifunctional nanofiber membranes via the simple electrospinning method. The antibacterial and photocatalytic properties of these materials are based on the generation of singlet oxygen formed by processes photosensitized by the tetraphenylporphyrin encapsulated in the nanofibers. The addition of magnetic features in the form of magnetic maghemite (γ-Fe2O3) nanoparticles stabilized by polyethylenimine enables additional functionalities, namely, the postirradiation formation of hydrogen peroxide and improved photothermal properties. This hybrid material allows for remote manipulation by a magnetic field, even in hazardous and/or highly microbial contaminant environments.

Development of new types of antimicrobial coatings is of utmost importance due to increasing problems with pathogen transmission from various infectious surfaces to human beings. In this study, new types of highly potent antimicrobial polyurethane composite films encapsulated by hydrophobic riboflavin-based carbon polymer dots are presented. Detailed structural, optical, antimicrobial, and cytotoxic investigations of these composites were conducted. Low-power blue light triggered the composites to eradicate Escherichia coli in 30 min, whereas the same effect toward Staphylococcus aureus was reached after 60 min. These composites also show low toxicity against MRC-5 cells. In this way, RF-CPD composites can be used for sterilization of highly touched objects in the healthcare industry.

Tuning the amphiphilicity of (aza)phthalocyanine hydrophobic cores by introducing multiple polyethylene glycol (PEG) moieties with controlled orientations of their (non)peripheral positions is an innovative approach to fabricating water-soluble macrocyclic materials. Although many water-soluble PEGylated macrocycles have been produced in this way, the ability to generate substances with PEG tails oriented outward from the macrocyclic plane in order to obtain non-aggregated, water soluble forms remains a challenge. In this study, we resolved this issue by developing a methods for the synthesis of four new dual directional PEG containing Zn(II)/Mg(II) amphiphiles (ZnPc-PEG, MgPc-PEG, ZnAzaPc-PEG and MgAzaPc-PEG). In addition, the non-aggregating behaviour, and photophysical and photochemical properties of these PEG-complexes were elucidated.

Novel water-soluble dihydroxophosphorus(V) complexes of sulphophenyl substituted porphyrazine (6), corrolazine (7) and its pyrazine fused derivative (8) were prepared and their spectral, acid-base and photophysical properties in aqueous solutions were studied. Due to the presence of eight SO3H groups, the compounds were fully monomeric (7 and 8) or only slightly aggregated (6) in water. Spectrophotometric titration revealed that the two stage deprotonation of axially bonded hydroxy groups can be achieved for porphyrazine 6 (pKa1 = 5.62, pKa2 = 9.13) and pyrazine fused corrolazine 8 (pKa1 = 6.5, pKa2 = 11.7), while only the first dissociation stage could be observed for corrolazine 7 (pKa1 = 9.94). The fluorescence emission of the corrolazines 7, 8 and especially porphyrazine 6 was low in water (ΦF = 0.086, 0.18, and 0.014, respectively) and completely quenched under basic conditions due to photoinduced electron transfer. In comparison with porphyrazine 6, the contraction of the macrocycle in the corrolazines 7 and 8 induced significant improvement of singlet oxygen production in water reaching values of ΦΔ = 0.56 and 0.43, respectively, which makes the corrolazines promising photosensitizers for photodynamic therapy. The observed evolution of the electronic absorption spectra and fluorescence quenching observed in a basic medium was explained using the model DFT calculations (cc-pvtz basis set) performed for the dihydroxophosphorus(V) complexes of unsubstituted porphyrazine and corrolazine and their mono- and doubly deprotonated forms.

Photosensitizers, which produce singlet oxygen O-2 ((1)Delta(g)) under light irradiation, have attracted much attention due to their application potential in medicine and material science. In this respect, we recently reported on cationic metallocene complexes with pendant N-donor moieties, which exhibited enhanced luminescence in the solid-state originating from their triplet states with luminescence quantum yields, Phi(L), up to approximately 0.52, unprecedented for this class of compounds. This finding suggested that these complexes can be efficient singlet oxygen photosensitizers. Herein, we evaluate the photogeneration of O-2((1)Delta(g)) by several Ti, Zr and Hf metal-locenes in dichloromethane solution, including recently described cationic derivatives. After excitation by UV A light, cationic Zr and Hf metallocenes stabilized by N-donor imine and pyridine moieties exhibited green, yellow or orange luminescence from long-lived(3) LMCT excited states (Phi(L) similar to 0.02 - 0.40 in argon-saturated solutions) and efficient O-2((1)Delta(g)) production (Phi(Delta) similar to 0.29 - 0.77 in air-saturated solutions). In contrast, parent neutral Zr complexes and cationic Ti derivatives with enhanced absorption of visible light, exhibited lesser ability to produce O-2((1)Delta(g)) (Phi(Delta) < 0.10), similar to Zr and Ti metallocene dihalogenides. The experimentally established spectroscopic and photophysical behavior was probed computationally at the TD-DFT level.

Despite the wide variety of strategies developed to combat pathogenic microorganisms, the infectious diseases they cause remain a worldwide health issue. Hence, the search for new disinfectants, which prevent infection spread, constitutes an extremely urgent task. One of the most promising methods is the use of photoactive compounds - photosensitizers, capable of generating reactive oxygen species, in particular, singlet oxygen (O2(1Δg)), which causes rapid and effective death of microorganisms of all types. In this work, we propose the utilization of the powdered cluster complex (Bu4N)2[{Mo6I8}(OTs)6] as a photoactive additive to commercially available fluoroplastic lacquer F-32L to create heterogeneous self-sterilizing coatings. We show that soaking of the prepared films in water for 60 days did not lead to a decrease in their photosensitization properties indicating their excellent stability. Moreover, the use of the cluster complex in the solid state allowed significant expansion of the operating wavelength range, which covers the UV region and a large part of the visible region (250-650 nm). The films displayed high photoantimicrobial activity against five common pathogens (bacteria and fungi) under white-light irradiation. Overall, the properties demonstrated make these materials promising for practical use in everyday outdoor and indoor disinfection since they are active under both sunlight and artificial lighting.

Persistent microbial contamination of medical implant surfaces is becoming a serious threat to public health. This is principally due to antibiotic-resistant bacterial strains and the formation of bacterial biofilms. The development of novel antibacterial materials that will effectively fight both Gram-positive and Gram-negative bacteria and prevent biofilm formation represents a big challenge for researchers in the last few decades. In the present work, we report an antibacterial hydrophobic carbon quantum dots/polyurethane nanocomposite (hCQD-PU), with enhanced antibacterial properties induced by pre-treatment with gamma-irradiation. Hydrophobic quantum dots (hCQDs), which are capable of generating reactive oxygen species (ROS) upon irradiation with low-power blue light (470 nm), have been integrated into the polyurethane (PU) polymer matrix to form a photoactive nanocomposite. To modify its physical and chemical properties and improve its antibacterial efficacy, various doses of gamma irradiation (1, 10, and 200 kGy) in the air environment were applied to the formed nanocomposite. Gamma-irradiation pre-treatment significantly influenced the rise in ROS production, therefore, the prooxidative activity under the blue-light illumination of hCQD-PU was also significantly improved. The best antibacterial activity was demonstrated by the hCQD-PU nanocomposite irradiated with a dose of 200 kGy, with the complete eradication of Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria after 15 min of exposure to the blue lamp.