Staff

Abstract:
Aiming at biomedical applications, the present work developed a new bio-nanocomposite fibrous mat based on natural rubber (NR) reinforced with 45S5 bioglass particles (BG) and cellulose nanowhiskers (CNW), which reveals excellent mechanical properties, good biocompatibility and bioactivity properties.
Analyses of the specimens were conducted by means of morphological observa-tions (SEM) and thermal analysis (TG/DTG), as well as mechanical tests used to verify the effect of the incorporation of BG particles and CNW on the ultimate properties of these flexible NR-CWN/BG fibrous membranes. An SEM analysis revealed that all filaments possessed a ribbon-like morphology, with increasing diameters as the BG concentration increased. This likely results from an increased viscosity of the solution used for fiber blowing. In comparison with neat NR fibrous mats, the ultimate mechanical properties of bio-nanocomposites were sig-nificantly improved due to the presence of CNW and BG particles dispersed in the
NR matrix. According to the TG/DTG analysis, the specimens' thermal stability was unaffected by the high BG content, and the thermal profiles were similar,
with isoprene chains decomposition of the NR occurring between 350 and 450C. In-vitro analysis on fibroblasts confirmed that the bio-nanocomposite fibrous mats
are noncytotoxic. It was found that fibrous mats enhanced cellular growth and hold great promise for tissue engineering applications.

Keywords:
bioactive particles, cellulose nanowhiskers, fibrous mat bio-nanocomposite, natural rubber

Abstract:
The sustainable transformation of bio-waste into usable, material has gained great scientific interest. In this paper, we have presented preparation of an activated carbon material from a natural mushroom (Suillus boletus) and explor its properties for supercapacitor and dye adsorption applications. The produced cell exhibited a single electrode capacitance of ∼247 F g−1 with the energy and power density of ∼35 Wh kg−1 and 1.3 kW kg−1, respectively. The cell worked well for ∼20,000 cycles with ∼30% initial declination in capacitance. Three cells connected in series glowed a 2.0 V LED for ∼1.5 min. Moreover, ultrafast adsorption of methylene blue dye onto the prepared carbon as an adsorbent was recorded with ∼100% removal efficiency in an equilibrium time of three minutes. The performed tests indicate that the mushroom-derived activated carbon has the potential to become a high-performance electrode material for supercapacitors and an adsorbent for real-time wastewater treatment applications.

Keywords:
Activated carbon, Amorphous material, Biomass, Polymer gel electrolyte, Supercapacitor, Dye adsorption

Abstract:
The fundamental aspect of the fabrication of microporous, fibrous biomaterials in form of scaffolds is the optimization of their surface properties to enhance cellular response. In this work, a novel approach to physico-chemical modification and bioactivity enhancement of electrospun fibrous polycaprolactone (PCL) nonwovens using soft X-ray/extreme ultraviolet (SXR/EUV) irradiation and exposure to a low-temperature, SXR/EUV induced, nitrogen and oxygen plasmas is presented for the first time. Chemical alterations and morphology of the fibrous structure of irradiated PCL mats were examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The impact of introduced changes on viability, morphology, and adhesion of L929 mouse fibroblasts was examined. It was found that simultaneous interaction of SXR/EUV radiation and N2 or O2 photoionized plasmas led to strong chemical decomposition of the surface of fibrous PCL mats. Also, mats’ spatial porous structure was not damaged and the fibers were not broken or fused. All modified samples demonstrated cyto-compatible and non-cytotoxic properties. Enhancement of L929 cell adhesion and increased proliferation were also observed.

Keywords:
Soft X-ray/extreme ultraviolet (SXR/EUV) radiation, Low-temperature plasma treatment, Electrospun polycaprolactone (PCL) nonwovens, XPS analysis, L929 mouse fibroblasts, Cytocompatibility enhancement

Abstract:
Anticancer therapies and regenerative medicine are being developed to destroy tumor cells, as well as remodel, replace, and support injured organs and tissues. Nowadays, a suitable three-dimensional structure of the scaffold and the type of cells used are crucial for creating bio-inspired organs and tissues. The materials used in medicine are made of non-degradable and degradable biomaterials and can serve as drug carriers. Developing flexible and properly targeted drug carrier systems is crucial for tissue engineering, regenerative medicine, and novel cancer treatment strategies. This review is focused on presenting innovative biomaterials, i.e., electrospun nanofibers, 3D-printed scaffolds, and hydrogels as a novel approach for anticancer treatments which are still under development and awaiting thorough optimization.

Keywords:
scaffolds, hydrogels, tissue engineering, polymers, anticancer treatments, cancer therapy, regenerative medicine

Abstract:
In the present work, we report the synthesis of surface modified activated carbon (AC). The surface of the activated carbon have been modified by using silver nanoparticles. The synthesis process is simple, cost effective and environment friendly. The modified-AC powders have been characterized by using X-ray diffraction, scanning electron microscopy and surface area and pore size measurements. The electrochemical performance of the prepared materials have been tested by fabricating symmetric configuration of EDLC by using magnesium-ion based polymer electrolytes. The cells have been tested by using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge technique. AC with 3 wt% of silver presents best results with specific capacitance of the order of 398 F g−1 energy density and power density of 55 Wh kg−1 and 2.4 kW kg−1 making it an interesting material for supercapacitor application.

Keywords:
supercapacitor, activated carbon-silver composite, gel polymer electrolyte, electrochemical studies

Abstract:
Injuries of the bone/cartilage and central nervous system are still a serious socio-economic problem. They are an effect of diversified, difficult-to-access tissue structures as well as complex regeneration mechanisms. Currently, commercially available materials partially solve this problem, but they do not fulfill all of the bone/cartilage and neural tissue engineering requirements such as mechanical properties, biochemical cues or adequate biodegradation. There are still many things to do to provide complete restoration of injured tissues. Recent reports in bone/cartilage and neural tissue engineering give high hopes in designing scaffolds for complete tissue regeneration. This review thoroughly discusses the advantages and disadvantages of currently available commercial scaffolds and sheds new light on the designing of novel polymeric scaffolds composed of hydrogels, electrospun nanofibers, or hydrogels loaded with nano-additives.

Keywords:
scaffolds, tissue engineering, polymers, electrospun nanofibers, hydrogels, nanoparticles, composites, injectable materials

Abstract:
Tissue engineering (TE) scaffolds have enormous significance for the possibility of regeneration of complex tissue structures or even whole organs. Three-dimensional (3D) printing techniques allow fabricating TE scaffolds, having an extremely complex structure, in a repeatable and precise manner. Moreover, they enable the easy application of computer-assisted methods to TE scaffold design. The latest additive manufacturing techniques open up opportunities not otherwise available. This study aimed to summarize the state-of-art field of 3D printing techniques in applications for tissue engineering with a focus on the latest advancements. The following topics are discussed: systematics of the available 3D printing techniques applied for TE scaffold fabrication; overview of 3D printable biomaterials and advancements in 3D-printing-assisted tissue engineering.

Keywords:
tissue engineering, 3D printing, biomaterials

Abstract:
Biodegradability or materials physicochemical stability are the key biomaterials selection parameters for various medical and tissue engineering applications. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a natural copolymer known from its biocompatibility with great support for cells growth and attachment on films and fibers. In our studies, the physicochemical properties of electrospun PHBV fibers and spin-coated films aged for 1, 4 and 8 weeks were analyzed using bulk (FTIR) and surface chemistry (XPS) methods and water contact angle. Further, we characterized the zeta potential changes after aging, by means of electrokinetic measurements, and cell responses to it, using NIH 3T3 murine fibroblasts. Colorimetric MTS cell viability test allowed the assessment of cell proliferation. Additionally, the morphology of fibroblasts and biointerfaces were studied by confocal laser and electron scanning microscopy (CLSM and SEM). These studies indicated that the activity, attachment and proliferation of fibroblasts is independent of aging of PHBV fibers and films. PHBV films show very stable zeta potential over 8 weeks of aging, opposite to PHBV fibers. Importantly, the flat film of PHBV increases cell proliferation, while the fibrous meshes are an excellent support for their stretching. The results of the study revealed clear advantages of PHBV films and fibrous meshes in cell-material interaction.

Keywords:
cell morphology, fibroblast, electrospun fibers, PHBV, Zeta potential

Abstract:
Electrospinning is a widely investigated process for forming nanofibers. Nanofibers in drug delivery systems are extensively tested due to its remarkable properties e.g. small pore size or large surface area. Recent articles have informed about formation of fibers using triaxial electrospinning in drug delivery systems. This paper summarizes the process of triaxial electrospinning and its application in drug delivery. Triaxial electrospinning has advantages in forming complex nanostructures for specific drug delivery applications. This paper summarizes the possibility to use triaxial electrospinning to resolve the problem of limited drug solubility, to protect biomolecules from hostile environment, and to control drug release kinetics, with the possibility of loading of various drugs. There are literature data evidencing the possibility to achieve sustained release with a border case of zero rate order kinetics. There is no doubt that triaxial electrospinning opens a new way to develop sophisticated nanomaterials for achieving the desired functional performances and to expand the applications in the drug delivery area. Triaxial electrospinning method is interdisciplinary area with great potential in nanotechnology.

Keywords:
triaxial electrospinning, complex nanostructures, drug delivery, desired functional performance, sustained/controlled release

Abstract:
Electric field strength and polarity in electrospinning processes and their effect on process dynamics and the physical properties of as-spun fibers is studied. Using a solution of the neutral polymer such as poly(methyl methacrylate) (PMMA) we explored the electrospun jet motion issued from a Taylor cone. We focused on the straight jet section up to the incipient stage of the bending instability and on the radius of the disk of the fibers deposited on the collecting electrode. A new correlation formula using dimensionless parameters was found, characterizing the effect of the electric field on the length of the straight jet, L˜E~E˜0.55. This correlation was found to be valid when the spinneret was either negatively or positively charged and the electrode grounded. The fiber deposition radius was found to be independent of the electric field strength and polarity. When the spinneret was negatively charged, L˜E was longer, the as-spun fibers were wider. The positively charged setup resulted in fibers with enhanced mechanical properties and higher crystallinity. This work demonstrates that often-overlooked electrical polarity and field strength parameters influence the dynamics of fiber electrospinning, which is crucial for designing polymer fiber properties and optimizing their collection.

Keywords:
fibers, electrical polarity, charges, electrospinning, PMMA, mechanical properties

Abstract:
Smart piezoelectric materials are of great interest due to their unique properties. Piezoelectric materials can transform mechanical energy into electricity and vice versa. There are mono and polycrystals (piezoceramics), polymers, and composites in the group of piezoelectric materials. Recent years show progress in the applications of piezoelectric materials in biomedical devices due to their biocompatibility and biodegradability. Medical devices such as actuators and sensors, energy harvesting devices, and active scaffolds for neural tissue engineering are continually explored. Sensors and actuators from piezoelectric materials can convert flow rate, pressure, etc., to generate energy or consume it. This paper consists of using smart materials to design medical devices and provide a greater understanding of the piezoelectric effect in the medical industry presently. A greater understanding of piezoelectricity is necessary regarding the future development and industry challenges.

Keywords:
polymers, smart materials, piezoelectric materials, inorganic materials, organic materials, biomedical devices

Abstract:
Polyvinylidene fluoride (PVDF) is one of the most important piezoelectric polymers. Piezoelectricity in PVDF appears in polar β and ɣ phases. Piezoelectric fibers obtained by means of electrospinning may be used in tissue engineering (TE) as a smart analogue of the natural extracellular matrix (ECM). We present results showing the effect of rotational speed of the collecting drum on morphology, phase content and in vitro biological properties of PVDF nonwovens. Morphology and phase composition were analyzed using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. It was shown that increasing rotational speed of the collector leads to an increase in fiber orientation, reduction in fiber diameter and considerable increase of polar phase content, both b and g. In vitro cell culture experiments, carried out with the use of ultrasounds in order to generate electrical potential via piezoelectricity, indicate a positive effect of polar phases on fibroblasts. Our preliminary results demonstrate that piezoelectric PVDF scaffolds are promising materials for tissue engineering applications, particularly for neural tissue regeneration, where the electric potential is crucial.

Keywords:
scaffolds, electrospinning, polyvinylidene fluoride, tissue engineering

Abstract:
Injury to the central or peripheral nervous systems leads to the loss of cognitive and/or sensorimotor capabilities, which still lacks an effective treatment. Tissue engineering in the post-injury brain represents a promising option for cellular replacement and rescue, providing a cell scaffold for either transplanted or resident cells. Tissue engineering relies on scaffolds for supporting cell differentiation and growth with recent emphasis on stimuli responsive scaffolds, sometimes called smart scaffolds. One of the representatives of this material group is piezoelectric scaffolds, being able to generate electrical charges under mechanical stimulation, which creates a real prospect for using such scaffolds in non-invasive therapy of neural tissue. This paper summarizes the recent knowledge on piezoelectric materials used for tissue engineering, especially neural tissue engineering. The most used materials for tissue engineering strategies are reported together with the main achievements, challenges, and future needs for research and actual therapies. This review provides thus a compilation of the most relevant results and strategies and serves as a starting point for novel research pathways in the most relevant and challenging open questions.

Keywords:
neural tissue engineering, piezoelectric scaffolds, smart materials, polymers

Abstract:
The paper presents an experimental study of a special non−linear low frequency system dedicated to vibration mitigation and energy recovery. The dual−function design was based on an autoparametric vibration system, which consists of an oscillator with an added pendulum vibration absorber. Its structure includes an energy harvesting device: a levitating magnet in a coil. The pendulum motion shows simultaneously the effects of vibration reduction and energy recovery. The influences of the magnet−coil configurations, and load resistances on vibration reduction and energy harvesting were studied in detail.

Keywords:
Experiment, Energy recovery, Pendulum, Vibration mitigation

Abstract:
Dental composites are based on polymer resin matrix which diminishes its volume during polymerization process due to joining of monomer chains [1]. It is the reason of polymerization shrinkage of each polymer material. Serious consequence of the shrinkage in dentistry is marginal leakage and secondary caries resulting from this [2]. Therefore, the develop a low shrinkage material is a big challenge in the manufacturing of dental composites. There are many methods of diminishing polymerization shrinkage. One group is focused on resin matrix composition, the second on filler selection [3] and the others on applying technique [4]. Literature presents a lot of methods of shrinkage measurements [1]. In previous study the Authors used the method based on microCT measurements [5]. In this paper a new approach has been presented. In this study, the new method of polymerization shrinkage was applied to evaluate the polymerization shrinkage of selected dental composites showing differences in composition.

Abstract:
Polymerization shrinkage of the resin-based dental composites constitutes a risk of the failure of the interfacial bonds as a result of shrinkage stresses. It may result in marginal leakage, premature failure of the restoration, and even micro-cracking of the tooth [1,2]. Therefore, the research for develop a low shrinkage material has been a goal in the manufacture of dental composites. The color restorative materials are very interesting and market demand for these products was increased recently. They are used especially in milk tooth as fissure sealing, for marking root canal openings or as decoration (tooth tattoo) [3]. In this study, the research of polymerization shrinkage of flow-type dental composites was conducted.

Keywords:
Piezo-nerve, scaffold, nanofibers, tissue engineering, stem cells

Keywords:
scaffolds, electro spinning, tissue engineering

Keywords:
scaffolds, electrospinning, polyvinylidene fluoride, tissue engineering