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- ItemEnhanced Adhesion of Electrospun Polycaprolactone Nanofibers to Plasma-Modified Polypropylene Fabric(MDPI, 2023-03-28) Janů, Lucie; Dvořáková, Eva; Polášková, Kateřina; Janůšová, Martina; Ryšánek, Petr; Chlup, Zdeněk; Kruml, Tomáš; Galmiz, Oleksandr; Nečas, David; Zajíčková, LenkaExcellent adhesion of electrospun nanofiber (NF) to textile support is crucial for a broad range of their bioapplications, e.g., wound dressing development. We compared the effect of several low- and atmospheric pressure plasma modifications on the adhesion between two parts of composite-polycaprolactone (PCL) nanofibrous mat (functional part) and polypropylene (PP) spunbond fabric (support). The support fabrics were modified before electrospinning by low-pressure plasma oxygen treatment or amine plasma polymer thin film or treated by atmospheric pressure plasma slit jet (PSJ) in argon or argon/nitrogen. The adhesion was evaluated by tensile test and loop test adapted for thin NF mat measurement and the trends obtained by both tests largely agreed. Although all modifications improved the adhesion significantly (at least twice for PSJ treatments), low-pressure oxygen treatment showed to be the most effective as it strengthened adhesion by a factor of six. The adhesion improvement was ascribed to the synergic effect of high treatment homogeneity with the right ratio of surface functional groups and sufficient wettability. The low-pressure modified fabric also stayed long-term hydrophilic (ten months), even though surfaces usually return to a non-wettable state (hydrophobic recovery). In contrast to XPS, highly surface-sensitive water contact angle measurement proved suitable for monitoring subtle surface changes.
- ItemSynthetic Data in Quantitative Scanning Probe Microscopy(MDPI, 2021-06-01) Nečas, David; Klapetek, PetrSynthetic data are of increasing importance in nanometrology. They can be used for development of data processing methods, analysis of uncertainties and estimation of various measurement artefacts. In this paper we review methods used for their generation and the applications of synthetic data in scanning probe microscopy, focusing on their principles, performance, and applicability. We illustrate the benefits of using synthetic data on different tasks related to development of better scanning approaches and related to estimation of reliability of data processing methods. We demonstrate how the synthetic data can be used to analyse systematic errors that are common to scanning probe microscopy methods, either related to the measurement principle or to the typical data processing paths.
- ItemAmine modification of calcium phosphate by low-pressure plasma for bone regeneration(Nature Portfolio, 2021-09-01) Kodama, Joe; Harumningtyas, Anjar Anggraini; Ito, Tomoko; Michlíček, Miroslav; Sugimoto, Satoshi; Kita, Hidekazu; Chijimatsu, Ryota; Ukon, Yuichiro; Kushioka, Junichi; Okada, Rintaro; Kamatani, Takashi; Hashimoto, Kunihiko; Tateiwa, Daisuke; Tsukazaki, Hiroyuki; Nakagawa, Shinichi; Takenaka, Shota; Makino, Takahiro; Sakai, Yusuke; Nečas, David; Zajíčková, Lenka; Hamaguchi, Satoshi; Kaito, TakashiRegeneration of large bone defects caused by trauma or tumor resection remains one of the biggest challenges in orthopedic surgery. Because of the limited availability of autograft material, the use of artificial bone is prevalent; however, the primary role of currently available artificial bone is restricted to acting as a bone graft extender owing to the lack of osteogenic ability. To explore whether surface modification might enhance artificial bone functionality, in this study we applied low-pressure plasma technology as next-generation surface treatment and processing strategy to chemically (amine) modify the surface of beta-tricalcium phosphate (beta-TCP) artificial bone using a CH4/N-2/He gas mixture. Plasma-treated beta-TCP exhibited significantly enhanced hydrophilicity, facilitating the deep infiltration of cells into interconnected porous beta-TCP. Additionally, cell adhesion and osteogenic differentiation on the plasma-treated artificial bone surfaces were also enhanced. Furthermore, in a rat calvarial defect model, the plasma treatment afforded high bone regeneration capacity. Together, these results suggest that amine modification of artificial bone by plasma technology can provide a high osteogenic ability and represents a promising strategy for resolving current clinical limitations regarding the use of artificial bone.
- ItemDeposition penetration depth and sticking probability in plasma polymerization of cyclopropylamine(Elsevier, 2021-02-02) Michlíček, Miroslav; Janů, Lucie; Dvořáková, Eva; Nečas, David; Zajíčková, LenkaUnderstanding the role of substrate geometry is vital for a successful optimization of low-pressure plasma polymerization on non-planar substrates used in bioapplications, such as porous materials or well plates. We investigated the altered transport of film-forming species and properties of the coatings for a cyclopropylamine and argon discharge using a combined analysis of the plasma polymer deposition on flat Si pieces, culture wells, microtrenches, a macrocavity, porous hydroxyapatite scaffolds and electrospun polycaprolactone nanofibrous mats. The aspect ratio of the well structures impacted mainly the deposition rate, whereas the film chemistry was affected only moderately. A large deposition penetration depth into the porous media indicated a relatively low sticking probability of film-forming species. A detailed analysis of microtrench step coverage and macrocavity deposition disproved the model of film-forming species with a single overall sticking probability. At least two populations with two different sticking probabilities were required to fit the experimental data. A majority of the film-forming species (76%) has a large sticking probability of 0.20 +/- 0.01, while still a significant part (24%) has a relatively small sticking probability of 0.0015 +/- 0.0002. The presented methodology is widely applicable for understanding the details of plasma-surface interaction and successful applications of plasma polymerization onto complex substrates.
- ItemCell type specific adhesion to surfaces functionalised by amine plasma polymers(Springer Nature, 2020-06-09) Křížková, Petra; Janů, Lucie; Medalová, Jiřina; Nečas, David; Michlíček, Miroslav; Kaushik, Preeti; Přibyl, Jan; Bartošíková, Jana; Manakhov, Anton; Bačáková, Lucie; Zajíčková, LenkaOur previously-obtained impressive results of highly increased C2C12 mouse myoblast adhesion to amine plasma polymers (PPs) motivated current detailed studies of cell resistance to trypsinization, cell proliferation, motility, and the rate of attachment carried out for fibroblasts (LF), keratinocytes (HaCaT), rat vascular smooth muscle cells (VSMC), and endothelial cells (HUVEC, HSVEC, and CPAE) on three different amine PPs. We demonstrated the striking difference in the resistance to trypsin treatment between endothelial and non-endothelial cells. The increased resistance observed for the non-endothelial cell types was accompanied by an increased rate of cellular attachment, even though spontaneous migration was comparable to the control, i.e., to the standard cultivation surface. As demonstrated on LF fibroblasts, the resistance to trypsin was similar in serum-supplemented and serum-free media, i.e., medium without cell adhesion-mediating proteins. The increased cell adhesion was also confirmed for LF cells by an independent technique, single-cell force spectroscopy. This method, as well as the cell attachment rate, proved the difference among the plasma polymers with different amounts of amine groups, but other investigated techniques could not reveal the differences in the cell behaviour on different amine PPs. Based on all the results, the increased resistance to trypsinization of C2C12, LF, HaCaT, and VSMC cells on amine PPs can be explained most probably by a non-specific cell adhesion such as electrostatic interaction between the cells and amine groups on the material surface, rather than by the receptor-mediated adhesion through serum-derived proteins adsorbed on the PPs.
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