Łukasz Kaniuk’s research while affiliated with AGH University of Krakow and other places

The enormous potential of electrospun polymer fibers allows for their development in the field of biomaterials for tissue engineering and wound healing. Electrospun fibers based on biodegradable polymers such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are an ideal material for the production of a biocompatible cell scaffold supporting wound closure and skin regeneration. The aim of this research was to create a fibrous PHBV scaffold supporting the 3D environment for anchoring and proliferation of keratinocytes. Moreover, hyaluronic acid (HA) has been used as a coating on PHBV fibers to improve the wound closure processes. ATR-FTIR results indicated the presence of HA in the PHBV scaffolds and UV–Vis analysis confirmed the release of HA from the fibers over 24h test. Importantly, this release of HA increase keratinocyte activity as well their proliferation leading to accelerated wound closure rate in the scratch tests. The designed HA-coated PHBV scaffolds demonstrate the great potential of surface-modified electrospun polymer fibers for wound healing.

The growing problem of skin diseases due to allergies often causing atopic dermatitis, which is characterized by itching, burning, and redness, constantly motivates researchers to look for solutions to soothe these effects by moisturizing skin properly. For this purpose, we combined poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun fibers with evening primrose oil (EPO) into a system of patches to ensure skin hydration. Moreover, the dressing or patch application requires appropriate stretchability and wettability of the electrospun material. Thus, we examined the mechanical properties of the PHBV blend with EPO, as well as changes in wettability of the fiber surface depending on the share of EPO additive in the blend. The effectiveness of the patches has been characterized using the water vapor transmission rate as well as by the skin moisturizing index. The thermal insulation effect of the patches on human skin has been verified as well. The patches made by combining the polymer with natural oil showed enhanced mechanical properties and increased skin hydration, indicating the potential applicability of PHBV-based patches. The presented discovery of PHBV patches with EPO is a prospective and alternative treatment for patients for whom current state-of-the-art methods do not bring satisfactory results.

Biodegradable polymeric biomaterials offer a significant advantage in disposable or fast-consuming products in medical applications. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is an example of a polyhydroxyalkanoate (PHA), i.e., one group of natural polyesters that are byproducts of reactions taking place in microorganisms in conditions with an excess carbon source. PHA polymers are a promising material for the production of everyday materials and biomedical applications. Due to the high number of monomers in the group, PHAs permit modifications enabling the production of copolymers of different compositions and with different proportions of individual monomers. In order to change and improve the properties of polymer fibers, PHAs are combined with either other natural and synthetic polymers or additives of inorganic phases. Importantly, electrospun PHBV fibers and mats showed an enormous potential in both the medical field (tissue engineering scaffolds, plasters, wound healing, drug delivery systems) and industrial applications (filter systems, food packaging). This Review summarizes the current state of the art in processing PHBV, especially by electrospinning, its degradation processes, and biocompatibility studies, starting from a general introduction to the PHA group of polymers.

Hybrid materials combining organic and inorganic compounds used as scaffolds are highly beneficial in bone regeneration. In this study, we successfully produced by blend electrospinning poly(3-hydroxybutyric acid-co-3-hydrovaleric acid) (PHBV) scaffolds enriched with hydroxyapatite (HA) particles to biomimic bone tissue for improved and faster regeneration processes. The morphology, fiber diameters, and composition of the scaffolds were investigated by scanning electron microscopy (SEM) techniques followed by focused ion beam (FIB) sectioning to verify HA particles integration with PHBV fibers. In vitro cell culture was performed for 7 days and followed with the cell proliferation test (CellTiter-Blue ® Assay). Additionally, cell integration with the scaffold was visualized by confocal and SEM imaging. We developed a simple way of obtaining hybrid scaffolds by electrospinning PHBV solution with HA particles without any post-processing. The PHBV + HA scaffold enhanced cell proliferation and filopodia formation responsible for cell anchoring within the created 3D environment. The obtained results show the great potential in the development of hybrid scaffolds stimulating bone tissue regeneration.

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.

Atopic dermatitis (AD) is a chronic, inflammatory skin condition, caused by wide genetic, environmental, or immunologic factors. AD is very common in children but can occur at any age. The lack of long-term treatments forces the development of new strategies for skin regeneration. Polycaprolactone (PCL) is a well-developed, tissue-compatible biomaterial showing also good mechanical properties. In our study, we designed the electrospun PCL patches with controlled architecture and topography for long-term release in time. Hemp oil shows anti-inflammatory and antibacterial properties, increasing also the skin moisture without clogging the pores. It can be used as an alternative cure for patients that do not respond to traditional treatments. In the study, we tested the mechanical properties of PCL fibers, and the hemp oil spreading together with the release in time measured on skin model and human skin. The PCL membranes are suitable material as patches or bandages, characterized by good mechanical properties and high permeability. Importantly, PCL patches showed release of hemp oil up to 55% within 6 h, increasing also the skin moisture up to 25%. Our results confirmed that electrospun PCL patches are great material as oil carriers indicating a high potential to be used as skin patches for AD skin treatment.

Atopic dermatitis (eczema) is a widespread disorder, with researchers constantly looking for more efficacious treatments. Natural oils are reported to be an effective therapy for dry skin, and medical textiles can be used as an alternative or supporting therapy. In this study, fibrous membranes from poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVB) with low and high molecular weights were manufactured to obtained nano- and micrometer fibers via electrospinning for the designed patches used as oil carriers for atopic skin treatment. The biocompatibility of PVB patches was analyzed using proliferation tests and scanning electron microscopy (SEM), which combined with focused ion beam (FIB) allowed for the 3D visualization of patches. The oil spreading tests with evening primrose, black cumin seed and borage were verified with cryo – SEM, showed the advantage nanofibers have over microfibers as carriers for low viscosity oils. The skin tests expressed the usability and the enhanced oil delivery performance for electrospun patches. We demonstrate that through material nano- and microstructure, commercially available polymers such as PVB have great potential to be deployed as biomaterial in medical applications, such as topical treatments for chronic skin conditions.

Surface potential of biomaterials is a key factor regulating cells responses, driving their adhesion and signaling in tissue regeneration. In this study we compared the surface and zeta potential of smooth and porous electrospun polycaprolactone (PCL) fibers, as well as PCL films, to evaluate their significance in bone regeneration. The fibers' surface potential was controlled by applying positive and negative voltage polarities during the electrospinning. The surface properties of the different PCL fibers and films were measured using X-ray photoelectron spectroscopy (XPS) and Kelvin probe force microscopy (KPFM), and the zeta potential using the electrokinetic technique. The effect of surface potential on the morphology of bone cells was examined using advanced microcopy, including 3D reconstruction based on scanning electron microscope with focused ion beam (FIB-SEM). Initial cell adhesion and collagen formation were studied using fluorescence microscopy and Sirius Red assay respectively, while calcium mineralization was confirmed with energy-dispersive x-ray (EDX) and Alzarin Red staining. These studies revealed that cell adhesion is driven by both the surface potential and morphology of PCL fibers. Furthermore, the ability to tune the surface potential of electrospun PCL scaffolds provides an essential electrostatic handle to enhance cell-material interaction and cellular activity, leading to controllable morphological changes.

The cellular response is the most crucial in vitro research. Materials' biocompatibility is determined based on cell proliferation and growth. Moreover, the topography of the scaffold surface is the key to enhance cell attachment and anchoring that importantly control further tissue development. Individual cell types have specific preferences regarding the type of surface and its geometry. In our research, we used poly(3-hydroxybutyric acid-co-3-hydrovaleric acid) PHBV to produce two types of substrate: a 3D structure of electrospun fibers and 2D flat films. The PHBV products were morphologically characterized by scanning electron microscopy (SEM). The cytocompatibility was evaluated with cell viability and proliferation using two different types of cells: human osteoblast-like cells (MG-63) and NIH 3 T3 murine fibroblast cells. The behaviour of both cell types was compared on the similar PHBV fiber scaffolds and films using two types of polystyrene (PS) based substrate for the cell culture study: unmodified PS that is not favourable for the attachment of cells and on tissue culture polystyrene (TCPS) plates, which are chemically modify to enhance cells attachment. The results clearly showed high biocompatibility of PHBV as both types of cells showed similar proliferation. These results indicated that PHBV scaffolds are suitable for the development of multifunctional substrates facilitating the growth of different types of tissue regardless of the 3D and 2D designed structures for regeneration purposes.

One of the most frequently applied polymers in regenerative medicine is polystyrene (PS), which is commonly used as a flat surface and requires surface modifications for cell culture study. Here, hierarchical composite meshes were fabricated via electrospinning PS with nylon 6 (PA6) to obtain enhanced cell proliferation, development, and integration with nondegradable polymer fibers. The biomimetic approach of designed meshes was verified with a scanning electron microscope (SEM) and MTS assay up to 7 days of cell culture. In particular, adding PA6 nanofibers changes the fibroblast attachment to meshes and their development, which can be observed by cell flattening, filopodia formation, and spreading. The proposed single-step manufacturing of meshes controlled the surface properties and roughness of produced composites, allowing governing cell behavior. Within this study, we show the alternative engineering of nondegradable meshes without post-treatment steps, which can be used in various applications in regenerative medicine.