Browsing by Author "Farooq, Muhammad"

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  • Affinity of Keratin Peptides for Cellulose and Lignin: A Fundamental Study toward Advanced Bio-Based Materials
    (2022-08-16) Nuutinen, Emmi-Maria; Valle-Delgado, Juan José; Kellock, Miriam; Farooq, Muhammad; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Keratin is a potential raw material to meet the growing demand for bio-based materials with special properties. Keratin can be obtained from feathers, a by-product from the poultry industry. One approach for keratin valorization is to use the protein to improve the properties of already existing cellulose and lignin-based materials to meet the requirements for replacing fossil-based plastics. To ensure a successful combination of keratin with lignocellulosic building blocks, keratin must have an affinity to these substrates. Hence, we used quartz crystal microbalance with a dissipation monitoring (QCM-D) technique to get a detailed understanding of the adsorption of keratin peptides onto lignocellulosic substrates and how the morphology of the substrate, pH, ionic strength, and keratin properties affected the adsorption. Keratin was fractionated from feathers with a scalable and environmentally friendly deep eutectic solvent process. The keratin fraction used in the adsorption studies consisted of different sized keratin peptides (about 1-4 kDa), which had adopted a random coil conformation as observed by circular dichroism (CD). Measuring keratin adsorption to different lignocellulosic substrates by QCM-D revealed a significant affinity of keratin peptides for lignin, both as smooth films and in the form of nanoparticles but only a weak interaction between cellulose and keratin. Systematic evaluation of the effect of surface, media, and protein properties enabled us to obtain a deeper understanding of the driving force for adsorption. Both the structure and size of the keratin peptides appeared to play an important role in its adsorption. The keratin-lignin combination is an attractive option for advanced material applications. For improved adsorption on cellulose, modifications of either keratin or cellulose would be required.
  • AFM Force Spectroscopy Reveals the Role of Integrins and Their Activation in Cell-Biomaterial Interactions
    (2020-03-16) Harjumäki, Riina; Zhang, Xue; Nugroho, Robertus Wahyu N.; Farooq, Muhammad; Lou, Yan Ru; Yliperttula, Marjo; Valle-Delgado, Juan José; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Transmembrane protein integrins play a key role in cell adhesion. Cell-biomaterial interactions are affected by integrin expression and conformation, which are actively controlled by cells. Although integrin structure and function have been studied in detail, quantitative analyses of integrin-mediated cell-biomaterial interactions are still scarce. Here, we have used atomic force spectroscopy to study how integrin distribution and activation (via intracellular mechanisms in living cells or by divalent cations) affect the interaction of human pluripotent stem cells (WA07) and human hepatocarcinoma cells (HepG2) with promising biomaterials-human recombinant laminin-521 (LN-521) and cellulose nanofibrils (CNF). Cell adhesion to LN-521-coated probes was remarkably influenced by cell viability, divalent cations, and integrin density in WA07 colonies, indicating that specific bonds between LN-521 and activated integrins play a significant role in the interactions between LN-521 and HepG2 and WA07 cells. In contrast, the interactions between CNF and cells were nonspecific and not influenced by cell viability or the presence of divalent cations. These results shed light on the underlying mechanisms of cell adhesion, with direct impact on cell culture and tissue engineering applications.
  • Biobased Nanomaterials─The Role of Interfacial Interactions for Advanced Materials
    (2023-03-08) Österberg, Monika; Henn, K. Alexander; Farooq, Muhammad; Valle-Delgado, Juan José
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    This review presents recent advances regarding biomass-based nanomaterials, focusing on their surface interactions. Plant biomass-based nanoparticles, like nanocellulose and lignin from industry side streams, hold great potential for the development of lightweight, functional, biodegradable, or recyclable material solutions for a sustainable circular bioeconomy. However, to obtain optimal properties of the nanoparticles and materials made thereof, it is crucial to control the interactions both during particle production and in applications. Herein we focus on the current understanding of these interactions. Solvent interactions during particle formation and production, as well as interactions with water, polymers, cells and other components in applications, are addressed. We concentrate on cellulose and lignin nanomaterials and their combination. We demonstrate how the surface chemistry of the nanomaterials affects these interactions and how excellent performance is only achieved when the interactions are controlled. We furthermore introduce suitable methods for probing interactions with nanomaterials, describe their advantages and challenges, and introduce some less commonly used methods and discuss their possible applications to gain a deeper understanding of the interfacial chemistry of biobased nanomaterials. Finally, some gaps in current understanding and interesting emerging research lines are identified.
  • Developing applications for biorefinery lignin: chemical modification and nanoparticle preparation
    (2023-08-22) Garcia, Elijah
     Kemian tekniikan korkeakoulu | Master's thesis
  • Eco-friendly Flame-Retardant Cellulose Nanofibril Aerogels by Incorporating Sodium Bicarbonate
    (2018-08-15) Farooq, Muhammad; Sipponen, Mika H.; Seppälä, Ari; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Cellulose nanofiber (CNF) aerogels offer excellent thermal insulation properties, but high flammability restricts their application. In this study, CNF aerogels were prepared by incorporating sodium bicarbonate (SBC), which effectively improved the fire retardancy without compromising the thermal conductivity of the aerogels, which was only 28 mW m-1 K-1. The minimum burning velocity of flame-retardant aerogels was 0.20 cm s-1 at 40 wt % of SBC, which is significantly lower compared to 5.84 cm s-1 of pure CNF aerogels. At the threshold concentration of 20 wt % SBC, the flame-retardant aerogel demonstrated flameless pyrolysis along with enhanced char formation. SBC additionally provides control over the microporosity and morphology, due to the concentration-dependent formation of lamellar layers during the preparation of aerogels. Overall, this work describes an efficient method for preparing flame-retardant CNF aerogels that could lay the foundation for next-generation bio-based insulation materials.
  • Fractionation of Technical Lignin from Enzymatically Treated Steam-Exploded Poplar Using Ethanol and Formic Acid
    (2022-12-09) Maltari, Riku; Kontro, Jussi; Koivu, Klaus; Farooq, Muhammad; Mikkilä, Joona; Zhang, Rui; Hildén, Kristiina; Sipilä, Jussi; Nousiainen, Paula A.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Lignocellulosic biorefineries produce lignin-rich side streams with high valorization potential concealed behind their recalcitrant structure. Valorization of these residues to chemicals, materials, and fuels increases the profitability of biorefineries. Fractionation is required to reduce the lignins’ structural heterogeneity for further processing. We fractionated the technical biorefinery lignin received after steam explosion and saccharification processes. More homogeneous lignin fractions were produced with high β-O-4′ and aromatic content without residual carbohydrates. Non-toxic biodegradable organic solvents like ethanol and formic acid were used for fractionation and can be adapted to the existing biorefinery processes. Macromolecular properties of the isolated fractions were carefully characterized by structural, chemical, and thermal methods. The ethanol organosolv treatment produced highly soluble lignin with a reasonable yield, providing a uniform material for lignin applications. The organosolv fractionation with formic acid and combined ethanol-formic acid produced modified lignins that, based on thermal analysis, are promising as thermoresponsive materials.
  • Lignin nanoparticle modifications
    (2022-09-16) Relander, Aura
     Kemiantekniikan korkeakoulu | Bachelor's thesis
  • Lignin Nanoparticles as an Interfacial Modulator in Tough and Multi-Resistant Cellulose–Polycaprolactone Nanocomposites Based on a Pickering Emulsions Strategy
    (2022-09) Kimiaei, Erfan; Farooq, Muhammad; Grande, Rafael; Meinander, Kristoffer; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Free-standing nanocellulosic films (nanopapers) emerge as attractive sustainable materials to replace traditional plastics. However, the moisture sensitivity of cellulose and its poor dispersion in hydrophobic polymers are challenges to its widespread application. Harnessing the inherent properties of cellulose, lignin, and polycaprolactone, a Pickering emulsion approach is proposed to produce multifunctional cellulose nanofibril (CNF) nanocomposite films. Aqueous CNF dispersion is combined with hydrophobic polycaprolactone (PCL) using colloidal lignin nanoparticles (CLPs) as the emulsion stabilizer. CNF–PCL nanocomposite films with over 134% increase in dry strength compared to nanocomposites without CLPs are fabricated. This interfacial engineering strategy results in a CNF-based nanocomposite with wet strength up to 87 MPa without any chemical modification or crosslinking agents. The mechanism behind the achieved excellent dry and wet strength and water resistance is investigated and it is suggested that it is due to the amphiphilic CLPs that are able to form non-covalent bonds with both cellulose and PCL, thus binding these together. Furthermore, the nanocomposite films’ protection against UV and oxidation is significantly enhanced by increasing the CLPs content. Our proposed interfacial engineering strategy can be generically applied to other polymer systems and shows a great potential to pave the way toward replacing fossil-based plastics.
  • Lignocellulosic building blocks for aerogel and nanocomposite applications
    (2021) Farooq, Muhammad
     School of Chemical Technology | Doctoral dissertation (article-based)
    Each new dawn is marking our success in the field of science and technology, fortifying our knowledge, but at the same time risks associated with the plethora of environmental challenges in the form of climate change, air and ocean pollution and use of fossil fuels are rapidly growing as well. In these circumstances, a paradigm shift from a fossil-based society to a greener, bio-based one is highly encouraging. The growing concerns associated with the end of life of plastics and new legislation from governments have generated a demand for lignocellulosic materials. Lignocellulosic biomass, consisting of the natural polymers, cellulose and lignin, have been recognized as possible raw material for innovative bio-based products with added value. In this work, two major components of lignocellulosic biomass, cellulose at its nanoscale morphology, termed as "cellulose nanofibrils" (CNF), obtained via fibrillation and "colloidal lignin nanoparticles" (CLPs), transformed through the self-assembly process of crude lignin, have been utilized as building block materials for diverse practical applications. Among different enticing features of CNF, its low thermal conductivity was emphasized by preparing flame-retardant CNF aerogels. The readily available sodium bicarbonate proved itself as an effective eco-friendly flame-retardant. Mixing CNF with sodium bicarbonate enabled the production of low-density aerogels with self-extinguishing behavior upon the removal of the flame source and decreased combustion velocity while retaining the good insulating properties of the aerogels. Due to the challenges posed by the hydrophilic nature of CNF, the second nano component of lignocellulosic biomass, "CLPs" were examined for their interfacial properties using surface-sensitive methods. The gained fundamental understanding was put forth to develop strong nanocomposites from CNF and CLPs. Both CLPs and CNF demonstrated excellent suitability for water-based systems and the prepared nanocomposite films showed a significant increase in toughness at an optimum ratio between CLPs and CNF. In response to the hydrophilic surface character of CNF and CLPs, the following work utilized a water-based PU system in combination with CNF to selectively hydrophobized one side of the nanocomposite film, retaining the hydrophilicity of the other side. The further exploration of CLPs as low-cost enzyme carriers for aqueous ester synthesis exhibited 95% of the synthetic activity under a high aqueous reaction medium. Enzyme immobilized c-CLPs demonstrated excellent stability under esterification conditions, reusability, and high molar yield of esterification reaction yield. In conclusion, we demonstrated that nano-morphologies of CNF and CLPs provide a new toolbox for designing products of biological-origin with the possibility to functionalize and modify the interface between different building components.
  • The role of lignin as interfacial compatibilizer in designing lignocellulosic-polyester composite films
    (2025-02) Kimiaei, Erfan; Farooq, Muhammad; Szymoniak, Paulina; Ahmadi, Shayan; Babaeipour, Sahar; Schönhals, Andreas; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Advancing nanocomposites requires a deep understanding and careful design of nanoscale interfaces, as interfacial interactions and adhesion significantly influence the physical and mechanical properties of these materials. This study demonstrates the effectiveness of lignin nanoparticles (LNPs) as interfacial compatibilizer between hydrophilic cellulose nanofibrils (CNF) and a hydrophobic polyester, polycaprolactone (PCL). In this context, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using advanced techniques such as quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), water contact angle (WCA) measurements, broadband dielectric spectroscopy (BDS), and inverse gas chromatography (IGC). QCM-D was employed to quantify the adsorption behavior of LNPs on CNF and PCL surfaces, demonstrating LNPs’ capability to interact with both hydrophilic and hydrophobic phases, thereby enhancing composite material properties. LNPs showed extensive adsorption on a CNF model film (1186 ± 178 ng.cm−2) and a lower but still significant adsorption on a PCL model film (270 ± 64 ng.cm−2). In contrast, CNF adsorption on a PCL model film was the lowest, with a sensed mass of only 136 ± 35 ng.cm−2. These findings were further supported by comparing the morphology and wettability of the films before and after adsorption, using AFM and WCA analyses. Then, to gain insights into the molecular-level interactions and molecular mobility within the composite in dry state, BDS was employed. The BDS results showed that LNPs improved the dispersion of PCL within the CNF network. To further investigate the impact of LNPs on the composites’ interfacial properties, IGC was employed. This analysis showed that the composite films containing LNPs exhibited lower surface energy compared to those composed of only CNF and PCL. The presence of LNPs likely reduced the availability of surface hydroxyl groups, thus modifying the physicochemical properties of the interface. These changes were particularly evident in the heterogeneity of the surface energy profile, indicating that LNPs significantly altered the interfacial characteristics of the composite materials. Overall, these findings emphasize the necessity to control the interfaces between components for next-generation nanocomposite materials across diverse applications.
  • Spatially confined lignin nanospheres for biocatalytic ester synthesis in aqueous media
    (2018-12-01) Sipponen, Mika Henrikki; Farooq, Muhammad; Koivisto, Jari; Pellis, Alessandro; Seitsonen, Jani; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Dehydration reactions proceed readily in water-filled biological cells. Development of biocatalysts that mimic such compartmentalized reactions has been cumbersome due to the lack of low-cost nanomaterials and associated technologies. Here we show that cationic lignin nanospheres function as activating anchors for hydrolases, and enable aqueous ester synthesis by forming spatially confined biocatalysts upon self-assembly and drying-driven aggregation in calcium alginate hydrogel. Spatially confined microbial cutinase and lipase retain 97% and 70% of their respective synthetic activities when the volume ratio of water to hexane increases from 1:1 to 9:1 in the reaction medium. The activity retention of industrially most frequently used acrylic resin-immobilized Candida antarctica lipase B is only 51% under similar test conditions. Overall, our findings enable fabrication of robust renewable biocatalysts for aqueous ester synthesis, and provide insight into the compartmentalization of diverse heterogeneous catalysts.
  • Stereoselectively water resistant hybrid nanopapers prepared by cellulose nanofibers and water-based polyurethane
    (2018-11-01) Sethi, Jatin; Farooq, Muhammad; Österberg, Monika; Illikainen, Mirja; Sirviö, Juho Antti
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Cellulose nanopapers, known for excellent mechanical properties, loses 90% of their stiffness in the wet conditions. In this study, we attempt to improve the wet mechanical properties of cellulose nanopaper by incorporating polyurethane by a novel and ecofriendly method. Water based PU was dispersed along with CNFs in water and hybrid nanopapers were prepared by draining water under vacuum followed by forced drying. These hybrid nanopapers have a gradient interpenetrating structure with PU concentrated towards one side and CNFs towards the other, which was confirmed by scanning electron microscopy, x-ray photoelectron spectroscopy and contact angle measurements. Because of this, the nanopapers are water resistant on one surface (PU rich side) and hydrophilic on the other (cellulose rich side), making them stereoselectively water resistant. When wetted with water on the PU side, the hybrid nanopaper with 10% PU is able to retain 65% modulus; on the other hand, the reference retains only 10% of the modulus. Similar results are seen in the tensile and the yield strength. Additionally, the hybrid nanopapers have higher elongation and improved thermal stability. The reported material is relevant to the applications such as flexible electronics and transparent displays.
  • Strong, Ductile, and Waterproof Cellulose Nanofibril Composite Films with Colloidal Lignin Particles
    (2019-02-11) Farooq, Muhammad; Zou, Tao; Riviere, Guillaume; Sipponen, Mika H.; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Brittleness has hindered commercialization of cellulose nanofibril (CNF) films. The use of synthetic polymers and plasticizers is a known detour that impairs biodegradability and carbon footprint of the product. Herein, we utilize a variety of softwood Kraft lignin morphologies to obtain strong and ductile CNF nanocomposite films. An optimum 10 wt % content of colloidal lignin particles (CLPs) produced films with nearly double the toughness compared to a CNF film without lignin. CLPs rendered the films waterproof, provided antioxidant activity and UV-shielding with better visible light transmittance than obtained with irregular lignin aggregates. We conclude based on electron microscopy, dynamic water sorption analysis, and tp-DSC that homogeneously distributed CLPs act as ball bearing lubricating and stress transferring agents in the CNF matrix. Overall, our results open new avenues for the utilization of lignin nanoparticles in biopolymer composites equipped with versatile functionalities for applications in food packaging, water purification, and biomedicine.
  • Three-Dimensional Printed Cell Culture Model Based on Spherical Colloidal Lignin Particles and Cellulose Nanofibril-Alginate Hydrogel
    (2020-05-11) Zhang, Xue; Morits, Maria; Jonkergouw, Christopher; Ora, Ari; Valle-Delgado, Juan José; Farooq, Muhammad; Ajdary, Rubina; Huan, Siqi; Linder, Markus; Rojas, Orlando; Sipponen, Mika Henrikki; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Three-dimensional (3D) printing has been an emerging technique to fabricate precise scaffolds for biomedical applications. Cellulose nanofibril (CNF) hydrogels have attracted considerable attention as a material for 3D printing because of their shear-thinning properties. Combining cellulose nanofibril hydrogels with alginate is an effective method to enable cross-linking of the printed scaffolds in the presence of Ca2+ ions. In this work, spherical colloidal lignin particles (CLPs, also known as spherical lignin nanoparticles) were used to prepare CNF-alginate-CLP nanocomposite scaffolds. High-resolution images obtained by atomic force microscopy (AFM) showed that CLPs were homogeneously mixed with the CNF hydrogel. CLPs brought antioxidant properties to the CNF-alginate-CLP scaffolds in a concentration-dependent manner and increased the viscosity of the hydrogels at a low shear rate, which correspondingly provide better shape fidelity and printing resolution to the scaffolds. Interestingly, the CLPs did not affect the viscosity at high shear rates, showing that the shear thinning behavior typical for CNF hydrogels was retained, enabling easy printing. The CNF-alginate-CLP scaffolds demonstrated shape stability after printing, cross-linking, and storage in Dulbecco's phosphate buffer solution (DPBS +) containing Ca2+ and Mg2+ ions, up to 7 days. The 3D-printed scaffolds showed relative rehydration ratio values above 80% after freeze-drying, demonstrating a high water-retaining capability. Cell viability tests using hepatocellular carcinoma cell line HepG2 showed no negative effect of CLPs on cell proliferation. Fluorescence microscopy indicated that HepG2 cells grew not only on the surfaces but also inside the porous scaffolds. Overall, our results demonstrate that nanocomposite CNF-alginate-CLP scaffolds have high potential in soft-tissue engineering and regenerative-medicine applications.
  • Toward waste valorization by converting bioethanol production residues into nanoparticles and nanocomposite films
    (2021-07) Riviere, Guillaume; Pion, Florian; Farooq, Muhammad; Sipponen, Mika H.; Koivula, Hanna; Jayabalan, Thangavelu; Pandard, Pacal; Marlair, Guy; Liao, Xun; Baumberger, Stephanie; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A “waste-valorization” approach was developed to transform recalcitrant hydrolysis lignin (HL) from second-generation bioethanol production into multifunctional bio-based products. The hydrolysis lignin (HL) was extracted with aqueous acetone, yielding two fractions enriched in lignin and cellulose, respectively. The soluble hydrolysis lignin (SHL) was converted into anionic and cationic colloidal lignin particles (CLPs and c-CLPs). The insoluble cellulose-rich fraction was transformed into lignocellulosic nanofibrils that were further combined with CLPs or c-CLPs to obtain nanocomposite films with tailored mechanical properties, oxygen permeability and antioxidant properties. To enable prospective applications of lignin in nanocomposite films and beyond, CLPs and c-CLPs were also produced from a soda lignin (SL) and the influence of the lignin type on the particle size and ecotoxicity was evaluated. Finally, the carbon footprint of the entire process from hydrolysis lignin to films was assessed and an integration to industrial scale was considered to reduce the energy consumption. While most previous work utilizes purified lignin and pristine and often purified cellulose fibers to produce nanomaterials, this work provides a proof of concept for utilizing the recalcitrant lignin-rich side stream of the bioethanol process as raw material for functional nanomaterials and renewable composites.