Carbon nanodots as photosensitizer in photodynamic inactivation of Rickettsia slovaca.

Carbon quantum dots (CQDs) are promising therapeutic agent due to their pro-oxidant, antioxidant, antiviral, antibacterial, and anticancer properties when exposed to visible light irradiation. Oxidative stress in bacteria is the main reason for bacteria death after exposure to blue light photoexcited quantum dots. Herein, we present the antibacterial activities of hydrophobic carbon quantum dots/polydimethylsiloxane nanocomposites, hydrophilic citric acid CQDs, and combinations of CQDs with methylene blue.

Thermoplastic Starch Processed under Various Manufacturing Conditions: Thermal and Electrical Properties.

Eco-friendly materials like carbohydrate-based polymers are important for a sustainable future. Starch is particularly promising because of its biodegradability and abundance but its processing to thermoplastic starch requires optimization. Here we developed thermoplastic maize starch materials based on three manufacturing protocols, namely: (1) starch/glycerol manual mixing and extrusion, (2) starch/glycerol manual mixing, extrusion, and kneading, (3) starch/glycerol/water manual mixing and kneading.

Polyvinyl alcohol/collagen composite scaffold reinforced with biodegradable polyesters/gelatin nanofibers for adipose tissue engineering.

Breast cancer has become the most diagnosed cancer type, endangering the health of women. Patients with breast resection are likely to suffer serious physical and mental trauma. Therefore, breast reconstruction becomes an important means of postoperative patient rehabilitation.

Electrical Conductivity of Rubber Composites with Varying Crosslink Density under Cyclic Deformation.

Studies addressing electroconductive composites based on rubber have attracted great interest for many engineering applications. To contribute to obtaining useful materials with reproducible behavior, this study focused on understanding the mechanism of conductivity changes during mechanical deformation for rubber composites based on styrene-butadiene rubber (SBR) or ethylene-propylene-diene terpolymer (EPDM) vulcanized for various times. The composites were characterized by static electrical conductivity, tensile testing, dynamic mechanical thermal analysis (DMTA), and crosslink density measurements.

Antibacterial Electrospun Polycaprolactone Nanofibers Reinforced by Halloysite Nanotubes for Tissue Engineering.

Due to its slow degradation rate, polycaprolactone (PCL) is frequently used in biomedical applications. This study deals with the development of antibacterial nanofibers based on PCL and halloysite nanotubes (HNTs). Thanks to a combination with HNTs, the prepared nanofibers can be used as low-cost nanocontainers for the encapsulation of a wide variety of substances, including drugs, enzymes, and DNA.

Thermoplastic Starch-Based Composite Reinforced by Conductive Filler Networks: Physical Properties and Electrical Conductivity Changes during Cyclic Deformation.

Conductive polymer composites (CPC) from renewable resources exhibit many interesting characteristics due to their biodegradability and conductivity changes under mechanical, thermal, chemical, or electrical stress. This study is focused on investigating the physical properties of electroconductive thermoplastic starch (TPS)-based composites and changes in electroconductive paths during cyclic deformation. TPS-based composites filled with various carbon black (CB) contents were prepared through melt processing.

Antibacterial photodynamic activity of hydrophobic carbon quantum dots and polycaprolactone based nanocomposite processed via both electrospinning and solvent casting method.

Inhabitation of various types of bacteria on different surfaces causes vital health problems worldwide. In this work, a wound dressing defeating bacterial infection had been fabricated. The antibacterial effect of polycaprolactone and hydrophobic carbon quantum dots (hCQDs) based nanocomposite has been presented.

Properties and structure of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) filaments for fused deposition modelling.

Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of highly precise complex three-dimensional objects for a large range of applications. The principle of FDM is an extrusion of the molten filament and gradual deposition of layers and their solidification. Potential applications in pharmaceutical and medical fields require the development of biodegradable and biocompatible thermoplastics for the processing of filaments.

Photodynamic-active smart biocompatible material for an antibacterial surface coating.

Here we present a new effective antibacterial material suitable for a coating, e.g., surface treatment of textiles, which is also time and financially undemanding.

Size effects of graphene nanoplatelets on the properties of high-density polyethylene nanocomposites: morphological, thermal, electrical, and mechanical characterization.

High-density polyethylene (HDPE)-based nanocomposites incorporating three different types of graphene nanoplatelets (GnPs) were fabricated to investigate the size effects of GnPs in terms of both lateral size and thickness on the morphological, thermal, electrical, and mechanical properties. The results show that the inclusion of GnPs enhance the thermal, electrical, and mechanical properties of HDPE-based nanocomposites regardless of GnP size. Nevertheless, the most significant enhancement of the thermal and electrical conductivities and the lowest electrical percolation threshold were achieved with GnPs of a larger lateral size.

Electrically Conductive, Transparent Polymeric Nanocomposites Modified by 2D TiCT (MXene).

The electrically conductive, transparent, and flexible self-standing thin nanocomposite films based on copolyamide matrix (coPA:Vestamelt X1010) modified with 2D TiCT (MXene) nanosheets were prepared by casting and their electrical, mechanical and optical properties and then, were investigated. The percolation threshold of the MXene filler within the coPA matrix was found to be 0.05 vol.

A Multifunctional Graphene Oxide Platform for Targeting Cancer.

Diagnosis of oncological diseases remains at the forefront of current medical research. Carbonic Anhydrase IX (CA IX) is a cell surface hypoxia-inducible enzyme functionally involved in adaptation to acidosis that is expressed in aggressive tumors; hence, it can be used as a tumor biomarker. Herein, we propose a nanoscale graphene oxide (GO) platform functionalized with magnetic nanoparticles and a monoclonal antibody specific to the CA IX marker.

Light-Induced Actuation of Poly(dimethylsiloxane) Filled with Graphene Oxide Grafted with Poly(2-(trimethylsilyloxy)ethyl Methacrylate).

This study serves to combine two approaches into one single step, to achieve a significant improvement of the light-induced actuation capabilities. Graphene oxide (GO) is an inert material, from the electrical and thermal conductivity point of view, and is incompatible with the usually-used poly(dimethylsiloxane) (PDMS) matrix. During surface-modification by surface-initiated atom transfer radical polymerization, the GO was transformed into a conducting and compatible material with the PDMS showing enormous light-induced actuation capability.

Graphene quantum dots inhibit T cell-mediated neuroinflammation in rats.

We investigated the therapeutic capacity of nano-sized graphene sheets, called graphene quantum dots (GQD), in experimental autoimmune encephalomyelitis (EAE), an animal model of immune-mediated central nervous system (CNS) damage. Intraperitoneally administered GQD (10 mg/kg/day) accumulated in the lymph node and CNS cells of Dark Agouti rats in which EAE was induced by immunization with spinal cord homogenate in complete Freund's adjuvant. GQD significantly reduced clinical signs of EAE when applied throughout the course of the disease (day 0-32), while the protection was less pronounced if the treatment was limited to the induction (day 0-7 post-immunization) or effector (from day 8 onwards) phase of the disease.

Low-cost light-induced therapy to treat rickettsial infection.

Antimicrobial photodynamic therapy uses a nontoxic photosensitizer with the assistance of harmless visible light to activate the photosensitizer. Consequently, the excited state of the photosensitizer interacts with molecular oxygen to produce reactive oxygen species, which have the antimicrobial effect. In this study, we evaluated the effect of photodynamic therapy on Vero cells infected with rickettsia using methylene blue as a photosensitizer along with red light.

Diversity of Coxiella-like and Francisella-like endosymbionts, and Rickettsia spp., Coxiella burnetii as pathogens in the tick populations of Slovakia, Central Europe.

Ticks are important vectors of pathogens affecting humans and animals worldwide. They do not only carry pathogens but diverse commensal and symbiotic microorganisms are also present in ticks. A molecular screening for tick-borne pathogens and endosymbionts was carried out in Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis inermis questing ticks collected in Slovakia.

Graphene quantum dots suppress proinflammatory T cell responses via autophagy-dependent induction of tolerogenic dendritic cells.

Graphene quantum dots (GQD) are atom-thick nanodimensional carbon sheets with excellent physico-chemical and biological properties, making them attractive for application in theranostics. However, their immunoregulatory properties are insufficiently investigated, especially in human primary immune cells. We found that non-toxic doses of GQD inhibit the production of proinflammatory and T helper (Th)1 cytokines, and augment the production of anti-inflammatory and Th2 cytokines by human peripheral blood mononuclear cells.

Antibacterial potential of electrochemically exfoliated graphene sheets.

Electrochemically exfoliated graphene is functionalized graphene with potential application in biomedicine. Two most relevant biological features of this material are its electrical conductivity and excellent water dispersibility. In this study we have tried to establish the correlation between graphene structure and its antibacterial properties.

Fast low-temperature plasma reduction of monolayer graphene oxide at atmospheric pressure.

We report on an ultrafast plasma-based graphene oxide reduction method superior to conventional vacuum thermal annealing and/or chemical reduction. The method is based on the effect of non-equilibrium atmospheric-pressure plasma generated by the diffuse coplanar surface barrier discharge in proximity of the graphene oxide layer. As the reduction time is in the order of seconds, the presented method is applicable to the large-scale production of reduced graphene oxide layers.

Elastic properties of poly(hydroxybutyrate) molecules.

Elasticity of various poly(hydroxybutyrate) (PHB) molecules of regular and irregular conformational structure was examined by the molecular mechanics (MM) calculations. Force - distance functions and the Young's moduli E were computed by stretching of PHB molecules. Unwinding of the 2(1) helical conformation H is characterized at small deformations by the Young's modulus E = 1.