Papers by Author: Lenka Martinová

Abstract: Nanospider^TM method allows preparation of nanofiber sheets with desired specific mass and fiber diameter between 100-600 nm. The fiber diameter can be modified by solvent system, concentration of polymer solution, and external conditions of the electrospinning process, in particular by air humidity and temperature. We have long experience with continual electrospinning from free surface of the polymer solution and in this case we focus on polymer blend polyamide 6/chitosan nanofiber form. Chitosan is an excellent material providing biocompatibility and numerous primary amine groups. On the other hand, polyamide 6 is well known and easy-to-prepare stable polymer guaranteeing sufficient mechanical properties. Blend nanofibers containing synthetic and natural polymers are usually difficult to continuously prepare. Natural polymer bring certain inhomogeneity due to varying chemical and physical properties of each brew. We compared chitosan from four different suppliers and finally fabricated homogenous and long-term stable layers. Successfully prepared nanofiber sheets were used as a support for enzyme immobilization. We showed that our layers can be used as a carrier for numerous biomolecules.

Abstract: In this study, silk nanofibre sheets were prepared by a needleless electrospinning from silk fibroin in a mixture of formic acid and calcium chloride. The influences of the concentration of calcium chloride on the properties of spinning solution, morphology of the silk electrospun fibres and the spinning performance of the spinning process were examined. The results show that calcium chloride can improve the solubility of silk fibroin in formic acid. The morphology of electrospun fibres was characterized by a scanning electron microscope (SEM), which indicates that the morphology of obtained fibres was influenced by the weight ratio of silk fibre to calcium chloride in the spinning solution. It was observed that the concentration of calcium chloride in the spinning solution influenced the diameter of the silk electrospun fibres, with an increase in the concentration of calcium chloride increasing the diameters of the electrospun fibres. The silk nanofibres had diameters ranging from 440 to 1900 nm. However, increasing the concentration of calcium chloride in the spinning solution had a less influence on the spinning performance of electrospinning process.

Abstract: In this study, nanofibres consisting of silk fibroin (SF) and gelatin (GP) with different composition ratio were fabricated by needleless electrospinning method. The influences of SF/GP blending ratio on the properties of spinning solution and the morphology of electrospun fibres were investigated. A variety of compositions of the silk fibroin/gelatin blend solutions were successfully electrospun into nanofibres sheet. The morphology of electrospun fibre was characterized by a scanning electron microscope (SEM) which indicates that the morphology of obtained fibres was influenced by the weight ratio of gelatin to silk fibroin in the spinning solution. It was observed that the blending ratio of gelatin to silk fibroin in spinning solution played an important role in spinning performance of the process and the diameter of obtained fibres. An increasing in gelatin content in blended solution resulted in bigger diameter of the obtained electrospun fibres. The silk fibroin/gelatin electrospun fibres had diameters ranging from 200 to 660 nm.

Abstract: This study was focused on the preparation of electrospunnanofibres from silk fibroin (SF)/gelatin (GP) blends solution using a roller electro spinning method. The effects of mixing ratio in SF/GP blend solution on properties of spinning solution (e.g., viscosity, conductivity and surface tension) and morphology of electrospunfibres were studied. The SF/GP blends solution containing up to the gelatin content of 30% could be electro spun into the continuous fibrous structure. Average diameter of SF/GP electrospunfibres were increased by increasing the amount of gelatin in spinning solution. The SF/GP electrospunfibres showed bigger diameter and broader diameter distribution than pure silk fibroin electrospunfibres. The SF/GP nanofibres had diameters ranging from 400 to 1300 nm.

Abstract: The new electrospinning technology NanospiderTM offering a realistic potential for industrial production was used for creation of nanofiber sheets from aqueous solutions of partially neutralized poly(acrylic) acid with crosslinking agent. Produced nanofiber sheet was crosslinked by heat treatment. Absorption capacity and rate of absorption were tested and compared with superabsorbent particles and commercial superabsorbent fibers. The morphology of electrospun fibers was observed using a scanning electron microscope (SEM). Possibilities of fiber diameter influence were studied.

Abstract: Recent advances in the preparation of nanofibre layers, especially using the Nanospider™ technology, allow prepare a sufficiently large area of nanofibrous layer of reproducible thickness and structure. Subsequently, it is possible to employ these layers as cell carriers and evaluate their efficiency in laboratory bioreactors. The construction of the functional hepatal bioreactor is particularly given by the positive response of hepatocyte cells to the used carrier layer as well as by the cell morphology, their viability and biological activity in certain period of time. We compared cell growth on collagen with nanofibres electrospun from selected copolymers of methacrylic esters (HEMA/EOEMA) and from differently prepared polycaprolactone (PCL) layers. The morphology was evaluated using Phaloidin/DAPI staining. On the nanofibres based on methacrylates, the cells survived and showed a common morphology comparing with cells grown on collagen (controls). On the PCL nanofibres, the cells attached well and showed a better growth than cells grown on collagen (controls). The results obtained in laboratory bioreactor proved the biochemical functionality of the studied system.