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Johanka Táborská,1 Andreu Blanquer,2,3 Eduard Brynda,1 Elena Filová,2 Lenka Stiborová,1 Věra Jenčová,4 Kristýna Havlíčková,4 Zuzana Riedelová,1 Tomáš Riedel1 1Department of Chemistry and Physics of Surfaces and Biointerfaces, Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czech Republic; 2Department of Biomaterials and Tissue Engineering, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; 3Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, Bellaterra, Spain; 4Department of Chemistry, Technical University of Liberec, Liberec, Czech RepublicCorrespondence: Tomáš Riedel, Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho namesti 2, 162 00 Prague 6, Czech Republic, Tel +420 296 809 333, Email riedel@imc.cas.czIntroduction: The formation of diabetic ulcers (DU) is a common complication for diabetic patients resulting in serious chronic wounds. There is therefore, an urgent need for complex treatment of this problem. This study examines a bioactive wound dressing of a biodegradable electrospun nanofibrous blend of poly(L-lactide-co-ϵ-caprolactone) and poly(ϵ-caprolactone) (PLCL/PCL) covered by a thin fibrin layer for sustained delivery of bioactive molecules.Methods: Electrospun PLCL/PCL nanofibers were coated with fibrin-based coating prepared by a controlled technique and enriched with human platelet lysate (hPL), fibroblast growth factor 2 (FGF), and vascular endothelial growth factor (VEGF). The coating was characterized by scanning electron microscopy and fluorescent microscopy. Protein content and its release rate and the effect on human saphenous vein endothelial cells (HSVEC) were evaluated.Results: The highest protein amount is achieved by the coating of PLCL/PCL with a fibrin mesh containing 20% v/v hPL (NF20). The fibrin coating serves as an excellent scaffold to accumulate bioactive molecules from hPL such as PDGF-BB, fibronectin (Fn), and α-2 antiplasmin. The NF20 coating shows both fast and a sustained release of the attached bioactive molecules (Fn, VEGF, FGF). The dressing significantly increases the viability of human saphenous vein endothelial cells (HSVECs) cultivated on a collagen-based wound model. The exogenous addition of FGF and VEGF during the coating procedure further increases the HSVECs viability. In addition, the presence of α-2 antiplasmin significantly stabilizes the fibrin mesh and prevents its cleavage by plasmin.Discussion: The NF20 coating supplemented with FGF and VEGF provides a promising wound dressing for the complex treatment of DU. The incorporation of various bioactive molecules from hPL and growth factors has great potential to support the healing processes by providing appropriate stimuli in the chronic wound.Keywords: human platelet lysate, diabetic ulcer, fibrin coating, growth factors, nanofibers, bioactive dressing

Active wound dressings are attracting extensive attention in soft tissue repair and regeneration, including bacteria-infected skin wound healing. As the wide use of antibiotics leads to drug resistance we present here a new concept of wound dressings based on the polycaprolactone nanofiber scaffold (NANO) releasing second generation lipophosphonoxin (LPPO) as antibacterial agent. Firstly, we demonstrated in vitro that LPPO released from NANO exerted antibacterial activity while not impairing proliferation/differentiation of fibroblasts and keratinocytes. Secondly, using a mouse model we showed that NANO loaded with LPPO significantly reduced the Staphylococcus aureus counts in infected wounds as evaluated 7 days post-surgery. Furthermore, the rate of degradation and subsequent LPPO release in infected wounds was also facilitated by lytic enzymes secreted by inoculated bacteria. Finally, LPPO displayed negligible to no systemic absorption. In conclusion, the composite antibacterial NANO-LPPO-based dressing reduces the bacterial load and promotes skin repair, with the potential to treat wounds in clinical settings.

Oriented fibres and materials based on orientated fibres have great potential for use in tissue engineering for tissues, where the arrangement of extracellular matrix is fundamental. The drawing method is based on mechanical pulling of a polymer solution out of its base droplet, resulting in a solidified fibre of determined geometrical characteristics. A new machine designed for lab scale drawing was invented enabling a repeatable quality of drawing conditions. The results demonstrate that it is possible to influence and define the fibre diameter and its distribution. From the in vitro experiments, it is evident that the aligned fibres guide the cell growth in the direction of the fibres. Moreover, the prepared fibres were functionalised with polypyrrole as an example of their versatility. These features make drawing an easy and suitable tool for the fabrication of scaffolds with a precise structure for tissues, e.g. nerve tissue.

Polypyrrole is one of the most investigated conductive polymers used for tissue engineering applications because of its advantageous properties and the ability to promote different cell types&rsquo, adhesion and proliferation. Together with &beta, cyclodextrin, which is capable of accommodating helpful biomolecules in its cavity, it would make a perfect couple for use as a scaffold for tissue engineering. Such scaffolds were prepared by the polymerisation of 6-(pyrrol-3-yl)hexanoic acid on polycaprolactone microfibres with subsequent attachment of &beta, cyclodextrin on the polypyrrole layer. The materials were deeply characterised by several physical and spectroscopic techniques. Testing of the cyclodextrin enriched composite scaffold revealed its better performance in in vitro experiments compared with pristine polycaprolactone or polypyrrole covered polycaprolactone scaffolds.

Supplemental Material for Drawn aligned polymer microfibres for tissue engineering by Kateřina Strnadová, Lukáš Stanislav, Ilona Krabicová, Filip Sabol, Jan Lukášek, Michal Řezanka, David Lukáš and Věra Jenčová in Journal of Industrial Textiles

Despite the extensive literature on organosilane hybrid materials, there are very few reports on the preparation of purely organosilane non-woven fibrous mats. Nevertheless, their use in various application fields may be of great importance regarding the global issue of polymer fibers and the toxicity of other compounds used so far in the composite polymer-organosilane fiber-manufacturing process. The greatest obstacle seems to be the supposed difficulty in the polymerization of organosilanes in a spinnable polymeric solution. In this work, we report the one-pot synthesis of electrospun organosilane fibers without any kinds of surfactants, low-molecular-weight polymeric gelators or spinnable polymers. The purely organosilane fibrous mats were prepared only via a suitable adjustment of the sol-gel processing parameters and were successfully produced an industrial electrospinning device, promising possible fabrication on a large scale. Moreover, the use of two differently-structured model benzene functionalized organoalkoxysilanes proves the possibility of designing a molecularly engineered material tailored to specific applications. These organosilane fibrous mats seem to be promising in various application fields, such as reusable catalysts, adsorption or conducting membranes or as novel biomaterials. This latter of these areas was preliminarily studied herein.

The gene encoding an integrase of Mason–Pfizer monkey virus (M-PMV) is located at the 3′-end of the pol open reading frame. The M-PMV integrase has not been previously isolated and characterized. We have now cloned, expressed, isolated, and characterized M-PMV integrase and compared its activities and primary structure with those of HIV-1 and other retroviral integrases. M-PMV integrase prefers untranslated 3′-region-derived long-terminal repeat sequences in both the 3′-processing and the strand transfer activity assays. While the 3′-processing reaction catalyzed by M-PMV integrase was significantly increased in the presence of Mn2+ and Co2+ and was readily detectable in the presence of Mg2+ and Ni2+ cations, the strand transfer activity was strictly dependent only on Mn2+. M-PMV integrase displays more relaxed substrate specificity than HIV-1 integrase, catalyzing the cleavage and the strand transfer of M-PMV and HIV-1 long-terminal repeat-derived substrates with similar efficiency. The structure-based sequence alignment of M-PMV, HIV-1, SIV, and ASV integrases predicted critical amino acids and motifs of M-PMV integrase for metal binding, interaction with nucleic acids, dimerization, protein structure maintenance and function, as well as for binding of human immunodeficiency virus type 1 and Rous avian sarcoma virus integrase inhibitors 5-CI-TEP, DHPTPB and Y-3.