Conversion of paper to film by ionic liquids : manufacturing process and properties

In this study, we investigate the “chemical welding” of paper with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) using a two-step process. First, the IL is transported into the structure of the paper as a water solution. Then, partial dissolution is achieved by activation with heat (80–95 °C), where the water evaporates and the surfaces of the fibres partially dissolve. The activated paper is washed with water to remove IL, and dried to fuse fibre surfaces into each other. The “chemically welded” paper structure has both elevated dry and wet strength. The treatment conditions can be adjusted to produce both paper-like materials and films. The most severe treatment conditions produce films that are fully transparent and their oxygen and grease barrier properties are excellent. As an all-cellulose material, the “chemically welded” paper is fully biodegradable and is a potential alternative to fossil fuel-based plastics.Peer reviewe

All-Wood Composite Material by Partial Fiber Surface Dissolution with an Ionic Liquid

Synthetic structural materials of high mechanical performance are typically either of large weight (for example, steels, and alloys) or involve complex manufacturing processes and thus have high cost or cause adverse environmental impact (for example, polymer-based and biomimetic composites). In this perspective, low-cost, abundant and nature-based materials, such as wood, represent particular interest provided they fulfill the requirements for advanced engineering structures and applications, especially when manufactured totally additive-free. Here, we report on a novel all-wood material concept based on delignification, partial surface dissolution using ionic liquid (IL) followed by densification resulting in a high-performance material. A delignification process using sodium chlorite in acetate buffer solution was applied to controllably delignify the entire bulk wooden material while retaining the highly beneficial structural directionality of wood. In a subsequent step, obtained delignified porous wood template was infiltrated with an IL 1-ethyl-3-methylimidazolium acetate, [EMIM]OAc and heat activated at 95 degrees C to partially dissolve the fiber surface. Afterward, treated wood was washed with water to remove IL and hot-pressed to gain a very compact cellulosic material with fused fibers while retaining unidirectional fiber orientation. The obtained cellulose materials were structurally, chemically, and mechanically characterized revealing superior tensile properties compared to native wood. Furthermore, suggested approach allows almost 8-fold tensile strength improvement in the direction perpendicular to fiber orientation, which is otherwise very challenging to achieve.Peer reviewe

Carboxymethyl Cellulose (CMC) Optical Fibers for Environment Sensing and Short-Range Optical Signal Transmission

Optical fibers are a key component in modern photonics, where conventionally used polymer materials are derived from fossil-based resources, causing heavy greenhouse emissions and raising sustainability concerns. As a potential alternative, fibers derived from cellulose-based materials offer renewability, biocompatibility, and biodegradability. In the present work, we studied the potential of carboxymethyl cellulose (CMC) to prepare optical fibers with a core-only architecture. Wet-spun CMC hydrogel filaments were cross-linked using aluminum ions to fabricate optical fibers. The transmission spectra of fibers suggest that the light transmission window for cladding-free CMC fibers was in the range of 550–1350 nm, wherein the attenuation coefficient for CMC fibers was measured to be 1.6 dB·cm–1 at 637 nm. CMC optical fibers were successfully applied in touch sensing and respiratory rate monitoring. Finally, as a proof-of-concept, we demonstrate high-speed (150 Mbit/s) short-distance signal transmission using CMC fibers (at 1310 nm) in both air and water media. Our results establish the potential of carboxymethyl cellulose-based biocompatible optical fibers for highly demanding advanced sensor applications, such as in the biomedical domain.publishedVersionPeer reviewe

Cellulose optical fiber for sensing applications

Cellulose materials offer new biodegradable alternatives for fabricating optical fibers for sensing applications. Unlike glass and polymer optical fibers, these environmentally friendly materials have intrinsic properties making them attractive candidates for functional optical fibers. Cellulose fibers are hygroscopic and thus can rapidly take water vapors from the surroundings and dry quickly. Cellulose-based optical fibers can be manufactured from regenerated cellulose or cellulose derivatives which offer a large property space. They can be resistant or soluble in water, and the refracting index of the material can be tuned as needed. In this work, feasibility for sensor applications of three different cellulose optical fibers have been tested: regenerated cellulose for water and humidity sensing, carboxymethyl cellulose for respiratory rate monitoring, and methylcellulose for short-range 150 Mbit/s signal transmission at 1310 nm. Therefore, fast signal transmission can be achieved with short cellulose-based sensor fibers. The work shows the scientific and technical potential of a novel optical material for photonics.acceptedVersionPeer reviewe

СОВРЕМЕННЫЕ ПОДХОДЫ К ПАТОГЕНЕЗУ ЛЕЙОМИОМЫ МАТКИ, ОСЛОЖНЕННОЙ МАТОЧНЫМ КРОВОТЕЧЕНИЕМ (ОБЗОР ЛИТЕРАТУРЫ)

ABSTRACT. The article describes the basic pathogenetic mechanisms of uterine bleeding occurrence in patients with uterine leiomyoma (UL). The pathogenesis of this disease is difficult and multi-factorial. Significant changes in the architectonics of the uterine vasculature are noted. Modern approaches to management of patients with UL and uterine bleeding are discussed from a clinical point of view using conservative, minimally invasive and surgical methods of treatment. РЕЗЮМЕ. В статье изложены основные патогенетические звенья возникновения маточных кровотечений у больных с лейомиомой матки (ЛМ). Патогенез данной патологии представляется сложным и многофакторным. Отмечены выраженные изменения в архитектонике сосудистой сети матки. С клинических позиций рассмотрены современные подходы к тактике ведения больных с ЛМ с маточными кровотечениями с применением консервативных, мини-инвазивных и хирургических методов лечения.

Selluloosapohjaiset biointerfaasit immunodiagnostisiin aplikaatioihin

In this work, the interactions between various proteins and modified cellulose surfaces were investigated. The work focused on the development of immobilization methods for the covalent attachment of specific immunological antibodies (proteins) onto cellulose substrate. The immobilization methods were explored using cellulose model surfaces and surface sensitive techniques, such as quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR). The highest adsorption of globular proteins on unmodified cellulose surfaces occurred at their respective isoelectric points, suggesting a non-electrostatic adsorption mechanism. An increased surface charge at the cellulose substrate was found to enhance the adsorption of all the proteins investigated. This indicated the presence of attractive electrostatic interactions and the adsorption was found to be mainly irreversible. In addition, the effect of oligosaccharide regions of proteins on their adsorption on cellulose was examined with one glycoprotein, avidin. The adsorption of avidin on cellulose was driven by a combination of electrostatic and non-electrostatic forces, and the adsorption was mainly irreversible. Moreover, the oligosaccharide regions of avidin decreased its adsorption strength to cellulose. In this work, several strategies for covalent immobilization of antibodies onto functionalized cellulose matrices were developed. The novel biointerfaces were capable of sensing antigens both selectively and quantitatively. The use of traditional conjugation chemistries typically leads to a random conformation of immobilized antibodies on the surfaces which in turn may decrease the ability of immobilized antibodies to bind antigens due to the sterical hindrances. Therefore, in this work, the antibodies were immobilized onto cellulose in more oriented manner using avidin-biotin linkage. This approach resulted in over two-fold higher antigen response when compared to those of the traditional conjugation chemistry. In the last part of this work, a biointerface was prepared on a water-resistant nanofibrillar cellulose (NFC) film. The NFC film was made amine reactive by using sequential TEMPO-mediated oxidation and EDC/NHS activation. Activated NFC-films were observed to bind antibodies covalently, and the antibodies could be deposited using standard inkjet printing techniques. The developed NFC-based biointerfaces are expected to open new venues for using cellulose in immunodiagnostic applications.Työssä tutkittiin proteiinien vuorovaikutusta pintamuokattujen selluloosamateriaalien kanssa hyödynnettäväksi immunodiagnostisissa sovelluksissa. Erityisesti työssä tutkittiin immunologisten vasta-aineiden kiinnittämistä pysyvästi selluloosapintoihin, ja kiinnitettyjen vasta-aineiden aktiivisuutta tunnistaa antigeenejä, vasta-aineille spesifisiä proteiineja. Edellä mainittujen proteiinien adsorptiota selluloosamateriaaleihin tutkittiin käyttäen pintaherkkiä menetelmiä, kuten kvartsikidevaakaa (QCM-D) ja pintaplasmoniresonanssi-instrumenttia (SPR) selluloosamallipintojen kanssa. Tutkitut proteiinit sitoutuivat modifioimattomiin selluloosapintoihin parhaiten niiden isoelektrisissä pisteissä, mikä osoittaa adsorption tapahtuvan pääasiassa muiden kuin sähköisten vuorovaikutusvoimien välityksellä. Selluloosapinnan kasvanut varaus kasvatti kaikkien tutkittujen proteiinien adsorptiota modifioiduille selluloosapinnoille. Tutkimuksessa selvitettiin myös yhden glykoproteiinin, avidiinin, adsorptiota muokatuille selluloosapinnoille, sekä avidiinin proteiinikuoren oligosakkaridiketjujen vaikutusta adsorptiomekanismeihin. Avidinin adsorptio selluloosapinnalla tapahtui sekä sähköisten ja ei-sähköisten vuorovaikutusten välityksellä ja sitoutuminen oli pysyvää. Tutkimuksessa havaittiin myös oligosakkaridiketjujen vähentävän avidinin adsorptiota selluloosapinnalle. Työssä kehitettiin menetelmiä sitoa vasta-aineita selluloosapintoihin vesifaasissa hyödyntäen ionisia polysakkarideja (karboksymetyyliselluloosa ja kitosaani), jotka adsorboituvat irreversiibelisti selluloosapintoihin. Tutkimuksissa havaittiin, että adsorboimalla tutkittuja ionisia polysakkarideja selluloosapintoihin, voidaan vasta-aineita sitoa selluloosapintaan kovalenttisten sidosten välityksellä. Kehitetyillä biointerfaasilla pystyttiin detektoimaan antigeenejä spesifisesti. Vasta-aineen konformaatio kiinteällä pinnalla vaikuttaa sen kykyyn sitoa tunnistettavaa antigeeniä. Perinteisessä kovalenttisessa immobilisaatiossa vasta-aineen konformaatiota ei pystytä hallitsemaan. Työssä tutkittiin menetelmää kiinnittää vasta-aineita selluloosapintoihin avidini-biotiinisidoksen avulla. Avidini-biotiinisidoksen avulla biointerfaasin kyky tunnistaa antigeenejä saatiin kaksinkertaistettua. Tutkimuksen viimeisessä vaiheessa kehitettiin biointerfaasi hyödyntäen nanoselluloosafilmejä, joiden pinnat modifioitiin käyttäen TEMPO-hapetusta ja EDC/NHS-aktivointia. Tutkitun aktivoidun nanoselluloosakalvon havaittiin sitovan vasta-aineita kovalenttisesti, ja niiden kiinnitys demonstroitiin mustesuihkutulostusta hyödyntäen. Kehitetty biointefaasi tarjoaa lujan ja kestävän alustan tulevaisuuden immunodiagnostisille sovelluksille