PEG-Functionalized Magnetite Nanoparticles for Modulation of Microbial Biofilms on Voice Prosthesis

This study reports the fabrication of nanostructured coatings based on magnetite, polyethyleneglycol, and biologically active molecule (polymyxin B-PM) for producing biofilm-resistant surfaces (voice prosthesis). Magnetite nanoparticles (MNPs) have been synthesized and functionalized using a co-precipitation method and were further deposited into thin coatings using the matrix-assisted pulsed laser evaporation (MAPLE) technique. The obtained nanoparticles and coatings were characterized by X-ray diffraction (XRD), thermogravimetric analysis with differential scanning calorimetry (TGA-DSC), scanning electron microscopy (SEM), transmission electron microscopy with selected area electron diffraction (TEM-SAED), Fourier-transform infrared spectroscopy (FT-IR), and infrared microscopy (IRM). Their antibiofilm activity was tested against relevant Staphylococcus aureus and Pseudomonas aeruginosa bacterial strains. The Fe3O4@PEG/PM surface of modified voice prosthesis sections reduced the number of CFU/mL up to four orders of magnitude in the case of S. aureus biofilm. A more significant inhibitory effect is noticed in the case of P. aeruginosa up to five folds. These results highlight the importance of new Fe3O4@PEG/PM in the biomedical field.

Thin Films of Nanocrystalline Fe(pz)[Pt(CN)4] Deposited by Resonant Matrix-Assisted Pulsed Laser Evaporation

Prior studies of the thin film deposition of the metal-organic compound of Fe(pz)Pt[CN]4 (pz = pyrazine) using the matrix-assisted pulsed laser evaporation (MAPLE) method, provided evidence for laser-induced decomposition of the molecular structure resulting in a significant downshift of the spin transition temperature. In this work we report new results obtained with a tunable pulsed laser, adjusted to water resonance absorption band with a maximum at 3080 nm, instead of 1064 nm laser, to overcome limitations related to laser–target interactions. Using this approach, we obtain uniform and functional thin films of Fe(pz)Pt[CN]4 nanoparticles with an average thickness of 135 nm on Si and/or glass substrates. X-ray diffraction measurements show the crystalline structure of the film identical to that of the reference material. The temperature-dependent Raman spectroscopy indicates the spin transition in the temperature range of 275 to 290 K with 15 ± 3 K hysteresis. This result is confirmed by UV-Vis spectroscopy revealing an absorption band shift from 492 to 550 nm related to metal-to-ligand-charge-transfer (MLCT) for high and low spin states, respectively. Spin crossover is also observed with X-ray absorption spectroscopy, but due to soft X-ray-induced excited spin state trapping (SOXIESST) the transition is not complete and shifted towards lower temperatures.

Organic Thin Films Deposited by Matrix-Assisted Pulsed Laser Evaporation (MAPLE) for Photovoltaic Cell Applications: A Review

Human society’s demand for energy has increased faster in the last few decades due to the world’s population growth and economy development. Solar power can be a part of a sustainable solution to this world’s energy need, taking into account that the cost of the renewable energy recently dropped owed to the remarkable progress achieved in the solar panels field. Thus, this inexhaustible source of energy can produce cheap and clean energy with a beneficial impact on the climate change. The considerable potential of the organic photovoltaic (OPV) cells was recently emphasized, with efficiencies exceeding 18% being achieved for OPV devices with various architectures. The challenges regarding the improvement in the OPV performance consist of the selection of the adequate raw organic compounds and manufacturing techniques, both strongly influencing the electrical parameters of the fabricated OPV devices. At the laboratory level, the solution-based techniques are used in the preparation of the active films based on polymers, while the vacuum evaporation is usually involved in the deposition of small molecule organic compounds. The major breakthrough in the OPV field was the implementation of the bulk heterojunction concept but the deposition of mixed films from the same solvent is not always possible. Therefore, this review provides a survey on the development attained in the deposition of organic layers based on small molecules compounds, oligomers and polymers using matrix-assisted pulsed laser evaporation (MAPLE)-based deposition techniques (MAPLE, RIR-MAPLE and emulsion-based RIR-MAPLE). An overview of the influence of various experimental parameters involved in these laser deposition methods on the properties of the fabricated layers is given in order to identify, in the forthcoming years, new strategies for enhancing the OPV cells performance.

Biofilm-Resistant Nanocoatings Based on ZnO Nanoparticles and Linalool

Biofilms represent an increasing challenge in the medical practice worldwide, imposing a serious threat to public health. As bacterial strains have developed antibiotic resistance, researcher’s attention has been extensively focused on developing more efficient antimicrobial strategies. In this context, the present study reports the synthesis, physicochemical characterization, ex vivo biodistribution, and in vitro evaluation of the capacity of nanostructured surfaces based on zinc oxide (ZnO) and biologically active molecules to modulate clinically relevant microbial biofilms. ZnO nanoparticles (NPs) were synthesized through a co-precipitation method without thermal treatment. The matrix-assisted pulsed laser evaporation (MAPLE) was applied for preparing nanostructured coatings based on ZnO NPs surface modified with linalool that were further characterized by X-ray diffraction (XRD), thermogravimetric analysis with differential scanning calorimetry (TGA-DSC), scanning electron microscopy (SEM), transmission electron microscopy with selected area electron diffraction (TEM-SAED), Fourier-transform infrared spectroscopy (FT-IR), and infrared microscopy (IRM). Histological analyses carried out at 7 days and 14 days after the intraperitoneal administration of linalool modified ZnO NPs revealed the absence of the latter from the brain, kidney, liver, lung, myocardium, and pancreas. Through in vitro assays on prokaryotic cells, it was proven that ZnO coatings hinder microbial biofilm formation of both Gram-positive and Gram-negative bacteria strains.

Pulsed Laser Deposition of Thin-Film Coatings in an Electrostatic Field

The work is devoted to the problem of thin metal coatings deposition on dielectric substrates using the method of target material pulsed laser evaporation. The main advantage of laser ablation over other methods of coating deposition is the possibility of using practically any material as a target, while the resulting films are characterized by a high correspondence of the phase and chemical composition to the target material. The possibility of using an electrostatic field to improve the efficiency of coating deposition process is considered. Under the action of an electric field formed between the plates of high-voltage electrodes, the ablation products leave the treatment area and settle on the substrate surface. Examples of coatings deposited under various ablation conditions are shown.

Case Report: Metachronous bilateral upper tract and bladder urothelial carcinoma: a long-term follow-up

Background: Upper tract urothelial carcinoma (UTUC) is a malignant disease of the urothelial cell lining the upper urinary tract from renal calyces, pelvises, and ureter down to the ureteral orifice. Urothelial carcinoma is a multifocal malignant tumor which tends to reoccur after treatment. Radical cystectomy shows that upper tract recurrence occurs in 0.75% to 6.4% of patients. The occurrence of contralateral UTUC after nephroureterectomy is rarer with a prevalence of 0.5%. Case presentation: The case of a 43-year-old male with metachronous bilateral UTUC was reported. The patient had undergone gemcitabine-cysplatine neoadjuvant chemotherapy followed by radical cystectomy and orthotopic neobladder for urothelial carcinoma of the bladder cT2N0M0. Left hydronephrosis was discovered three months after the procedure. The patient was diagnosed with left UTUC cT4N0M0 of renal pyelum after a series of examinations. A left open radical nephroureterectomy was conducted to remove the mass followed by adjuvant chemotherapy. This was followed up with routine ultrasound and magnetic resonance imaging (MRI) every three months with a “tumor-free” period of 26 months. Meanwhile, the patient was re-admitted with fever and an increase in creatinine value of 4.3. After further workups, the patient was diagnosed with UTUC cT2N0M0 of the right renal pyelum. A kidney sparring approach with laser evaporation of the tumor was conducted followed by eight cycles of Gemcitabine intracavity antegrade per nephrostomy. After the regimen was finished, an MRI evaluation was conducted to assess treatment results, and the mass had decreased. Conclusions: This report showed a rare case of urothelial cell carcinoma recurrences. From bladder urothelial carcinoma to left UTUC and then to contralateral UTUC. It is important to evaluate the upper tract to reduce the risk of recurrence.

Rubrene Thin Films with Viably Enhanced Charge Transport Fabricated by Cryo-Matrix-Assisted Laser Evaporation

Among organic semiconductors, rubrene (RB; C42H28) is of rapidly growing interest for the development of organic and hybrid electronics due to exceptionally long spin diffusion length and carrier mobility up to 20 cm2V−1s−1 in single crystals. However, the fabrication of RB thin films resembling properties of the bulk remains challenging, mainly because of the RB molecule’s twisted conformation. This hinders the formation of orthorhombic crystals with strong π–π interactions that support the band transport. In this work, RB films with a high crystalline content were fabricated by matrix-assisted laser evaporation and the associated structure, composition, and transport properties are investigated. Enhanced charge transport is ascribed to the crystalline content of the film. Spherulitic structures are observed on top of an amorphous RB layer formed in the initial deposition stage. In spherulites, orthorhombic crystals dominate, as confirmed by X-ray diffraction and the absorption and Raman spectra. Surprisingly, nanowires several microns in length are also detected. The desorption/ionization mass and X-ray photoelectron spectra consistently show minimal material decomposition and absence of RB peroxides. The observed carrier mobility up to 0.13 cm2V−1s−1, is close to the technologically accepted level, making these rubrene films attractive for spintronic and optoelectronic applications.

Isoflavonoid-Antibiotic Thin Films Fabricated by MAPLE with Improved Resistance to Microbial Colonization

Staphylococcus aureus (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) bacteria represent major infectious threats in the hospital environment due to their wide distribution, opportunistic behavior, and increasing antibiotic resistance. This study reports on the deposition of polyvinylpyrrolidone/antibiotic/isoflavonoid thin films by the matrix-assisted pulsed laser evaporation (MAPLE) method as anti-adhesion barrier coatings, on biomedical surfaces for improved resistance to microbial colonization. The thin films were characterized by Fourier transform infrared spectroscopy, infrared microscopy, and scanning electron microscopy. In vitro biological assay tests were performed to evaluate the influence of the thin films on the development of biofilms formed by Gram-positive and Gram-negative bacterial strains. In vitro biocompatibility tests were assessed on human endothelial cells examined for up to five days of incubation, via qualitative and quantitative methods. The results of this study revealed that the laser-fabricated coatings are biocompatible and resistant to microbial colonization and biofilm formation, making them successful candidates for biomedical devices and contact surfaces that would otherwise be amenable to contact transmission.