Ultrasonication effects on graphene composites in neural cell cultures.

Spinal cord injuries and neurodegenerative diseases, including Parkinson's, Alzheimer's, and traumatic brain injuries, remain challenging to treat. Nowadays, neural stem cell therapies excite high expectations within academia. The increasing demand for innovative solutions in regenerative medicine has drawn considerable attention to graphene materials. Due to unique properties, carbon materials are increasingly used as cellular scaffolds. They provide a biological microenvironment supporting cell adhesion and proliferation. The topography and mechanical properties of the graphene culture surface influence the forces exerted by the cells on their extracellular matrix. Which consequently affects the cell proliferation and differentiation. As a result, material properties such as stiffness, elasticity and mechanical strength play an important role in stem cells' growth and life. The ink unification process is crucial while the layer homogeneity is essential for obtaining suitable surface for specific cell growth. Different ink unification processes were tested to achieve appropriate layer homogeneity and resistivity to successfully applied the GNPs layers in neural cell electrostimulation. The GNP coatings were then used to electrostimulate mouse NE-4C neural stem cells. In this study, the authors investigated how the stimulation voltage amplitude's value affects cell behaviour, particularly the number of cells. Sinusoidal alternating current was used for stimulation. Three different values of stimulation voltage amplitude were investigated: 5, 10, and 15 V. It was noticed that a lower stimulation voltage amplitude had the most favourable effect on the stem cell count.

A Functionalized Membrane Layer as Part of a Dressing to Aid Wound Healing.

PURPOSE: This study is an approach to a dressing platform based on support functionalized with oxygenating factors within an alginate layer, constituting a safe and even contact surface for interface with a wound. METHODS: An alginate layer with incorporated oxygenating elements deposited on the support patch was assessed. As an oxygenating factor, perfluorooctyl was applied, and the layer coatings in two options, cross-linked and not, were evaluated. The function of human dermal fibroblast cells cultured in the presence of these constructs was analyzed, as well as their morphology using flow cytometry, fluorescence microscopy, and scanning electron microscopy. In addition, the membrane coating material was assessed using FTIR, AFM, and SEM-EDX characterization. RESULTS: The applied membrane coatings adsorbed on the patch ensured the viability of the human fibroblasts cultured on the membranes during 10 days of culture. However, on the sixth day of culture, the percentage of live cells grown in the presence of cross-linked alginate with oxygenating factor ((ALG-PFC)net) was significantly higher than that of the cells cultured in the presence of the alginate coatings alone. SEM-EDX analysis of the (ALG-PFC)net confirmed the presence of oxygenating and cross-linking factors. In addition, the regular granular branched structure of the layer coating material involving the oxygenating and cross-linking factors was observed using the AFM technique. CONCLUSION: The topography of the layer coating material involving the oxygenating and cross-linking factors ensures an even contact surface for interface with the wound. Considering 5-day intervals between dressing replacements, the platform with an oxygenating configuration ensuring the growth and morphology of the human fibroblasts can be recommended at this time as an element of a dressing system.

Polyelectrolyte Membrane Nanocoatings Aimed at Personal Protective and Medical Equipment Surfaces to Reduce Coronavirus Spreading.

The study of the surface of membrane coatings constructed with adsorbed coronavirus (COV) was described to test their suitability for the antiviral activity for application in personal protective and medical equipment. The nanocoating based on polyethyleneimine (PEI) or polystyrene sulfonate (PSS) with metallic nanoparticles incorporated was investigated using the AFM technique. Moreover, the functioning of human lung cells in a configuration with the prepared material with the adsorbed coronavirus was studied using microscopic techniques and flow cytometry. The mean values of the percentage share of viable cells compared with the control differed by a maximum of 22%. The results showed that PEI and PSS membrane layer coatings, modified with chosen metallic nanoparticles (AuNPs, AgNPs, CuNPs, FeNPs) that absorb COV, could support lung cells' function, despite the different distribution patterns of COV on designed surfaces as well as immobilized lung cells. Therefore, the developed membrane nanocoatings can be recommended as material for biomedical applications, e.g., medical equipment surfaces to reduce coronavirus spreading, as they adsorb COV and simultaneously maintain the functioning of the eukaryotic cells.

Composite Membrane Dressings System with Metallic Nanoparticles as an Antibacterial Factor in Wound Healing.

Wound management is the burning problem of modern medicine, significantly burdening developed countries' healthcare systems. In recent years, it has become clear that the achievements of nanotechnology have introduced a new quality in wound healing. The application of nanomaterials in wound dressing significantly improves their properties and promotes the healing of injuries. Therefore, this review paper presents the subjectively selected nanomaterials used in wound dressings, including the metallic nanoparticles (NPs), and refers to the aspects of their application as antimicrobial factors. The literature review was supplemented with the results of our team's research on the elements of multifunctional new-generation dressings containing nanoparticles. The wound healing multiple molecular pathways, mediating cell types, and affecting agents are discussed herein. Moreover, the categorization of wound dressings is presented. Additionally, some materials and membrane constructs applied in wound dressings are described. Finally, bacterial participation in wound healing and the mechanism of the antibacterial function of nanoparticles are considered. Membranes involving NPs as the bacteriostatic factors for improving wound healing of skin and bones, including our experimental findings, are discussed in the paper. In addition, some studies of our team concerning the selected bacterial strains' interaction with material involving different metallic NPs, such as AuNPs, AgNPs, Fe3O4NPs, and CuNPs, are presented. Furthermore, nanoparticles' influence on selected eukaryotic cells is mentioned. The ideal, universal wound dressing still has not been obtained; thus, a new generation of products have been developed, represented by the nanocomposite materials with antibacterial, anti-inflammatory properties that can influence the wound-healing process.

A Composite Membrane System with Gold Nanoparticles, Hydroxyapatite, and Fullerenol for Dual Interaction for Biomedical Purposes.

Background: Wound dressing plays a vital role in post-operative aftercare. There is the necessity to develop dressings for application on the border of soft and hard tissue. This study aimed to develop multifunctional polyelectrolyte layers enhanced by hydroxyapatite nanoparticles, gold nanoparticles (AuNPs), and/or fullerenol nanocomposites to achieve a wound dressing that could be applied on the bone-skin interface. Methods: Constructed shells were examined using TEM, STEM, and EDX techniques. The human osteoblasts or fibroblasts were immobilized within the shells. The systems morphology was assessed using SEM. The functioning of cells was determined by flow cytomery. Moreover, the internalization of AuNPs was assessed. Results: Involvement of fullerenol and/or hydroxyapatite nanoparticles influenced the immobilized cell systems morphology. Membranes with fullerenol and hydroxyapatite nanoparticles were observed to block the internalization of AuNPs by immobilized hFOB cells. Conclusions: The designed bilayer membranes incorporating fullerenol, and bacteriostatic elements, prevented the internalization of AuNPs by hFOB cells and ensured the proper counts and morphology of eukaryotic cells. The developed material can be recommended for dressings at the bone-skin interface.

Nanocomposite Membrane Scaffolds for Cell Function Maintaining for Biomedical Purposes.

Nanocomposite multilayered membrane coatings have been widely used experimentally to enhance biomedical materials surfaces. By the selection of reliable components, such systems are functionalized to be adjusted to specific purposes. As metal nanoparticles can reduce bacterial cell adhesion, the idea of using gold and silver nanoparticles of unique antimicrobial properties within membrane structure is outstandingly interesting considering dressings facilitating wound healing. The study was aimed to explore the interface between eukaryotic cells and wound dressing materials containing various nanoelements. The proposed systems are based on polyethyleneimine and hydroxyapatite thin layers incorporating metallic nanoparticles (silver or gold). To examine the structure of designed materials scanning electron and transmission electron microscopies were applied. Moreover, Fourier-transform infrared and energy-dispersive X-ray spectroscopies were used. Additionally, water contact angles of the designed membranes and their transport properties were estimated. The functioning of human fibroblasts was examined via flow cytometry to assess the biocompatibility of developed shells in the aspect of their cytotoxicity. The results indicated that designed nanocomposite membrane scaffolds support eukaryotic cells' functioning, confirming that the elaborated systems might be recommended as wound healing materials.

Printed Graphene Layer as a Base for Cell Electrostimulation-Preliminary Results.

Nerve regeneration through cell electrostimulation will become a key finding in regenerative medicine. The procedure will provide a wide range of applications, especially in body reconstruction, artificial organs or nerve prostheses. Other than in the case of the conventional polystyrene substrates, the application of the current flow in the cell substrate stimulates the cell growth and mobility, supports the synaptogenesis, and increases the average length of neuron nerve fibres. The indirect electrical cell stimulation requires a non-toxic, highly electrically conductive substrate material enabling a precise and effective cell electrostimulation. The process can be successfully performed with the use of the graphene nanoplatelets (GNPs)-the structures of high conductivity and biocompatible with mammalian NE-4C neural stem cells used in the study. One of the complications with the production of inks using GNPs is their agglomeration, which significantly hampers the quality of the produced coatings. Therefore, the selection of the proper amount of the surfactant is paramount to achieve a high-quality substrate. The article presents the results of the research into the material manufacturing used in the cell electrostimulation. The outcomes allow for the establishment of the proper amount of the surfactant to achieve both high conductivity and quality of the coating, which could be used not only in electronics, but also-due to its biocompatibility-fruitfully applied to the cell electrostimulation.

Polyelectrolyte Membrane with Hydroxyapatite and Silver Nanoparticles as a Material for Modern Wound Dressings.

Modern wound dressings not only play a covering role but also facilitate the function of the wound, contributing to a faster healing process. In this paper, we present a polyelectrolyte system with nanosized elements that could stimulate the growth of eukaryotic cells while providing antimicrobial properties, which may be recommended as a potential dressing material. The proposed platform consisted of polyethyleneimine, hydroxyapatite, and silver nanoparticles and was characterized using various macroscopic techniques. The constructed membrane scaffold was evaluated with immobilized WEHI 164 cells as a model system for cells sustained at the interface of bone and skin. Moreover, the bacteriostatic function of the designed membrane material was evaluated using different bacterial strains.

An initial evaluation of cytotoxicity, genotoxicity and antibacterial effectiveness of a disinfection liquid containing silver nanoparticles alone and combined with a glass-ionomer cement and dentin bonding systems.

BACKGROUND: Bacterial reinfection of dental cavities remains an unsolved clinical problem. The search for methods enabling the limitation of the bacterial factor has become the fundamental goal of the dental materials research. Silver nanoparticles (AgNPs) are used as disinfection agents. An incomplete polymerization of the polymer resins combined with AgNPs, along with the increase of the release of the unbound monomers, have been found. OBJECTIVES: The aim of this study was to evaluate the vitality of the human dental pulp stem cells (DPSCs) in response to a disinfection agent containing silver and gold nanoparticles (NPs), different bonding systems, glass-ionomer cement (GIC), and their combinations with the disinfection agent. Also, the influence of these materials both on the secretory function of DPSCs and on their antibacterial properties was established. MATERIAL AND METHODS: Cytotoxicity (MTT assay) and genotoxicity (enzyme-linked immunosorbent assay - ELISA) assays were used in the study. Antibacterial features were assessed with the optical density (OD) measurement of the bacteria (Streptococcus mutans, Streptococcus salivarius and Lactobacillus acidophilus) kept in dental materials. RESULTS: The disinfection liquid proved to be biocompatible. However, it relevantly interfered with the total-etch bonding system in terms of vitality, which may have serious clinical implications. Its combination with the self-etching system was biocompatible, yet it impaired the antibacterial action of the system. An enhancement of antibacterial action of GIC with AgNPs was found. CONCLUSIONS: The disinfection liquid and GIC were biocompatible toward the DPSCs in terms of cytotoxicity and genotoxicity. Simultaneous usage of AgNPs with other dental materials did not affect the biocompatibility of the used materials. The disinfection liquid and GIC acted as antibacterial agents against all studied bacteria species. Used together with GIC and the total-etch bonding system, the disinfection liquid seemed to be efficient toward bacteria, yet it relevantly impaired the antibacterial action of self-etching systems.

Gold Nanoparticle-Modified Poly(vinyl chloride) Surface with Improved Antimicrobial Properties for Medical Devices.

Despite the significant technological progress achieved in the past decades in the medical field, device-related infections carry a heavy social and economic burden. Surface modification of medical equipment is one of the most interesting approaches employed to improve the antibacterial activity of a material. Herein, we developed a process for the gold nanoparticle modification of a poly(vinyl chloride) laryngeal tube, which typically serves as an airway management device. In our study, we focused specifically on increasing the antimicrobial properties of the material while maintaining its biocompatibility. We applied two different modification methods to the poly(vinyl chloride) laryngeal tube. An increase in the antimicrobial activity of the surface was observed for both methods. In addition, the adsorption of bacterial cells on the material surface was assessed. We determined that the number of colonies cultured in the presence of the gold nanoparticle-modified samples or absorbed to the material surface decreased significantly compared with the control group. The trend was observed for both Gram-positive and Gram-negative strains. Moreover, it was established that the designed material did not exhibit a lethal impact on a control cell line. Finally, we noted discrepancies in the growth of bacteria cultured in the presence of modified or unmodified PVC material as well as differences in cell adherence to its surface. The proposed poly(vinyl chloride) modifications are most effective against Gram-positive bacteria, especially L. monocytogenes. Nevertheless, it ought to be emphasized that due to their different properties, each strain requires an individual approach.

Stabilized nanosystem of nanocarriers with an immobilized biological factor for anti-tumor therapy.

OBJECTIVE: The inadequate efficiency of existing therapeutic anti-cancer regiments and the increase in the multidrug resistance of cancer cells underscore the need to investigate novel anticancer strategies. The induction of apoptosis in tumors by cytotoxic agents produced by pathogenic microorganisms is an example of such an approach. Nevertheless, even the most effective drug should be delivered directly to targeted sites to reduce any negative impact on other cells. Accordingly, the stabilized nanosystem (SNS) for active agent delivery to cancer cells was designed for further application in local anti-tumor therapy. A product of genetically modified Escherichia coli, listeriolysin O (LLO), was immobilized within the polyelectrolyte membrane (poly(ethylenimine)|hyaluronic acid) shells of 'LLO nanocarriers' coupled with the stabilizing element of natural origin. METHODS AND RESULTS: The impact of LLO was evaluated in human leukemia cell lines in vitro. Correspondingly, the influence of the SNS and its elements was assessed in vitro. The viability of targeted cells was evaluated by flow cytometry. Visualization of the system structure was performed using confocal microscopy. The membrane shell applied to the nanocarriers was analyzed using atomic force microscopy and Fourier transform infrared spectroscopy techniques. Furthermore, the presence of a polyelectrolyte layer on the nanocarrier surface and/or in the cell was confirmed by flow cytometry. Finally, the structural integrity of the SNS and the corresponding release of the fluorescent solute listeriolysin were investigated. CONCLUSION: The construction of a stabilized system offers LLO release with a lethal impact on model eukaryotic cells. The applied platform design may be recommended for local anti-tumor treatment purposes.