Browsing by Author "Huan, Siqi"
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Item Acetylated Nanocellulose for Single-Component Bioinks and Cell Proliferation on 3D-Printed Scaffolds(AMER CHEMICAL SOC, 2019-05-22) Ajdary, Rubina; Huan, Siqi; Zanjanizadeh Ezazi, Nazanin; Xiang, Wenchao; Grande, Rafael; Santos, Hélder A.; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of HelsinkiNanocellulose has been demonstrated as a suitable material for cell culturing, given its similarity to extracellular matrices. Taking advantage of the shear thinning behavior, nanocellulose suits three-dimensional (3D) printing into scaffolds that support cell attachment and proliferation. Here, we propose aqueous suspensions of acetylated nanocellulose of a low degree of substitution for direct ink writing (DIW). This benefits from the heterogeneous acetylation of precursor cellulosic fibers, which eases their deconstruction and confers the characteristics required for extrusion in DIW. Accordingly, the morphology of related 3D-printed architectures and their performance during drying and rewetting as well as interactions with living cells are compared with those produced from typical unmodified and TEMPO-oxidized nanocelluloses. We find that a significantly lower concentration of acetylated nanofibrils is needed to obtain bioinks of similar performance, affording more porous structures. Together with their high surface charge and axial aspect, acetylated nanocellulose produces dimensionally stable monolithic scaffolds that support drying and rewetting, required for packaging and sterilization. Considering their potential uses in cardiac devices, we discuss the interactions of the scaffolds with cardiac myoblast cells. Attachment, proliferation, and viability for 21 days are demonstrated. Overall, the performance of acetylated nanocellulose bioinks opens the possibility for reliable and scale-up fabrication of scaffolds appropriate for studies on cellular processes and for tissue engineering.Item Adsorption and Assembly of Cellulosic and Lignin Colloids at Oil/Water Interfaces(AMER CHEMICAL SOC, 2019-01-22) Bai, Long; Greca, Luiz G.; Xiang, Wenchao; Lehtonen, Janika; Huan, Siqi; Nugroho, Robertus Wahyu N.; Tardy, Blaise L.; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and MaterialsThe surface chemistry and adsorption behavior of submicrometer cellulosic and lignin particles have drawn wide-ranging interest in the scientific community. Here, we introduce their assembly at fluid/fluid interfaces in Pickering systems and discuss their role in reducing the oil/water interfacial tension, limiting flocculation and coalescence, and endowing given functional properties. We discuss the stabilization of multiphase systems by cellulosic and lignin colloids and the opportunities for their adoption. They can be used alone, as dual components, or in combination with amphiphilic molecules for the design of multiphase systems relevant to household products, paints, coatings, pharmaceutical, foodstuff, and cosmetic formulations. This invited feature article summarizes some of our work and that of colleagues to introduce the readers to this fascinating and topical area.Item All-Aqueous Liquid Crystal Nanocellulose Emulsions with Permeable Interfacial Assembly(AMERICAN CHEMICAL SOCIETY, 2020-10-27) Bai, Long; Huan, Siqi; Zhao, Bin; Zhu, Ya; Esquena, Jordi; Chen, Feng; Gao, Guang; Zussman, Eyal; Chu, Guang; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Center for Biomedical Research Network (CIBER); University of British Columbia; Technion - Israel Institute of Technology; Northeast Forestry UniversityWe report on the formation of water-in-water liquid crystal emulsions with permeable colloidal assemblies. Rodlike cellulose nanocrystals (CNC) spontaneously self-assemble into a helical arrangement with the coexistence of nonionic, hydrophilic polyethylene glycol (PEG) and dextran, whereas the two polymer solutions are thermodynamically incompatible. Stable water-in-water emulsions are easily prepared by mixing the respective CNC/polymer solutions, showing micrometric CNC/PEG dispersed droplets and a continuous CNC/dextran phase. With time, the resulting emulsion demixes into an upper, droplet-lean isotropic phase and a bottom, droplet-rich cholesteric phase. Owing to the osmotic pressure gradient between PEG and dextran phases, target transfer of cellulose nanoparticles occurs across the water/water interface to reassemble into a liquid crystal-in-liquid crystal emulsion with global cholesteric organization. The observed structural, optical, and temporal evolution confirm that the colloidal particles in the two immiscible phases experience short-range interactions and form long-range assemblies across the interface.Item Chirality from Cryo-Electron Tomograms of Nanocrystals Obtained by Lateral Disassembly and Surface Etching of Never-Dried Chitin(AMERICAN CHEMICAL SOCIETY, 2020-06-23) Bai, Long; Kämäräinen, Tero; Xiang, Wenchao; Majoinen, Johanna; Seitsonen, Jani; Grande, Rafael; Huan, Siqi; Liu, Liang; Fan, Yimin; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Department of Applied Physics; Bio-based Colloids and Materials; Biohybrid Materials; Nanjing Forestry UniversityThe complex nature of typical colloids and corresponding interparticle interactions pose a challenge in understanding their self-assembly. This specifically applies to biological nanoparticles, such as those obtained from chitin, which typically are hierarchical and multidimensional. In this study, we obtain chitin nanocrystals by one-step heterogeneous acid hydrolysis of never-dried crab residues. Partial deacetylation facilitates control over the balance of electrostatic charges (ζ-potential in the range between +58 and +75 mV) and therefore affords chitin nanocrystals (DE-ChNC) with axial aspect (170-350 nm in length), as determined by cryogenic transmission electron microscopy and atomic force microscopy. We find that the surface amines generated by deacetylation, prior to hydrolysis, play a critical role in the formation of individual chitin nanocrystals by the action of a dual mechanism. We directly access the twisting feature of chitin nanocrystals using electron tomography (ET) and uncover the distinctive morphological differences between chitin nanocrystals extracted from nondeacetylated chitin, ChNC, which are bundled and irregular, and DE-ChNC (single, straight nanocrystals). Whereas chitin nanocrystals obtained from dried chitin precursors are known to be twisted and form chiral nematic liquid crystals, our ET measurements indicate no dominant twisting or handedness for the nanocrystals obtained from the never-dried source. Moreover, no separation into typical isotropic and anisotropic phases occurs after 2 months at rest. Altogether, we highlight the critical role of drying the precursors or the nanopolysaccharides to develop chirality.Item Formulation and Stabilization of Concentrated Edible Oil-in-Water Emulsions Based on Electrostatic Complexes of a Food-Grade Cationic Surfactant (Ethyl Lauroyl Arginate) and Cellulose Nanocrystals(AMER CHEMICAL SOC, 2018-05-14) Bai, Long; Xiang, Wenchao; Huan, Siqi; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and MaterialsWe report on high-internal-phase, oil-in-water Pickering emulsions that are stable against coalescence during storage. Viscous, edible oil (sunflower) was emulsified by combining naturally derived cellulose nanocrystals (CNCs) and a food-grade, biobased cationic surfactant obtained from lauric acid and L-arginine (ethyl lauroyl arginate, LAE). The interactions between CNC and LAE were elucidated by isothermal titration calorimetry (ITC) and supplementary techniques. LAE adsorption on CNC surfaces and its effect on nanoparticle electrostatic stabilization, aggregation state, and emulsifying ability was studied and related to the properties of resultant oil-in-water emulsions. Pickering systems with tunable droplet diameter and stability against oil coalescence during long-term storage were controllably achieved depending on LAE loading. The underlying stabilization mechanism was found to depend on the type of complex formed, the LAE structures adsorbed on the cellulose nanoparticles (as unimer or as adsorbed admicelles), the presence of free LAE in the aqueous phase, and the equivalent alkane number of the oil phase (sunflower and dodecane oils were compared). The results extend the potential of CNC in the formulation of high-quality and edible Pickering emulsions. The functional properties imparted by LAE, a highly effective molecule against food pathogens and spoilage organisms, open new opportunities in food, cosmetics, and pharmaceutical applications, where the presence of CNC plays a critical role in achieving synergistic effects with LAE.Item Heteroaggregation effects on Pickering stabilization using oppositely charged cellulose nanocrystal and nanochitin(Elsevier Science Ltd., 2023-01-01) Guo, Shasha; Zhu, Ya; Xu, Wenyang; Huan, Siqi; Li, Jun; Song, Tao; Bai, Long; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Materials Chemistry of Cellulose; South China University of Technology; University of British ColumbiaPickering emulsions are stabilized using complexes of cellulose nanocrystals (CNC) and nanochitin (NCh). The colloidal behavior and heteroaggregation in aqueous media are studied in relation to complex formation and net charge. The complexes are remarkably effective in stabilizing oil-in-water Pickering emulsions under conditions of slightly net positive or negative charges, as determined by the CNC/NCh mass ratio. Close to charge neutrality (CNC/NCh ~5), large heteroaggregates form, resulting in unstable emulsions. By contrast, under net cationic conditions, interfacial arrest of the complexes leads to non-deformable emulsion droplets with high stability (no creaming for 9 months). At given CNC/NCh concentrations, emulsions with up to 50% oil fraction are produced. This study shows how to control emulsion properties beyond consideration of the typical formulation variables, for instance, through adjusting CNC/NCh ratio or charge stoichiometry. We highlight the possibilities that are available for emulsion stabilization by using a combination of polysaccharide nanoparticles.Item High Internal Phase Oil-in-Water Pickering Emulsions Stabilized by Chitin Nanofibrils : 3D Structuring and Solid Foam(AMERICAN CHEMICAL SOCIETY, 2020-03-04) Zhu, Ya; Huan, Siqi; Bai, Long; Ketola, Annika; Shi, Xuetong; Zhang, Xiao; Ketoja, Jukka A.; Rojas, Orlando J.; Department of Bioproducts and Biosystems; School services, CHEM; Bio-based Colloids and Materials; Bio-based Colloids and Materials; VTT Technical Research Centre of FinlandChitin nanofibrils (NCh, ∼10 nm lateral size) were produced under conditions that were less severe compared to those for other biomass-derived nanomaterials and used to formulate high internal phase Pickering emulsions (HIPPEs). Pre-emulsification followed by continuous oil feeding facilitated a "scaffold" with high elasticity, which arrested droplet mobility and coarsening, achieving edible oil-in-water emulsions with internal phase volume fraction as high as 88%. The high stabilization ability of rodlike NCh originated from the restricted coarsening, droplet breakage and coalescence upon emulsion formation. This was the result of (a) irreversible adsorption at the interface (wettability measurements by the captive bubble method) and (b) structuring in highly interconnected fibrillar networks in the continuous phase (rheology, cryo-SEM, and fluorescent microscopies). Because the surface energy of NCh can be tailored by pH (protonation of surface amino groups), emulsion formation was found to be pH-dependent. Emulsions produced at pH from 3 to 5 were most stable (at least for 3 weeks). Although at a higher pH NCh was dispersible and the three-phase contact angle indicated better interfacial wettability to the oil phase, the lower interdroplet repulsion caused coarsening at high oil loading. We further show the existence of a trade-off between NCh axial aspect and minimum NCh concentration to stabilize 88% oil-in-water HIPPEs: only 0.038 wt % (based on emulsion mass) NCh of high axial aspect was required compared to 0.064 wt % for the shorter one. The as-produced HIPPEs were easily textured by taking advantage of their elastic behavior and resilience to compositional changes. Hence, chitin-based HIPPEs were demonstrated as emulgel inks suitable for 3D printing (millimeter definition) via direct ink writing, e.g., for edible functional foods and ultralight solid foams displaying highly interconnected pores and for potential cell culturing applications.Item Layer-by-Layer Deposition of Low-Solid Nanochitin Emulgels Creates Porous Structures for High Cell Attachment and Proliferation(American Chemical Society, 2023-06-07) Zhu, Ya; Kankuri, Esko; Zhang, Xue; Wan, Zhangmin; Wang, Xin; Huan, Siqi; Bai, Long; Liu, Shouxin; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of Helsinki; University of British Columbia; Northeast Forestry UniversityDirect ink writing (DIW) is a customizable platform to engineer complex constructs from biobased colloids. However, the latter usually display strong interactions with water and lack interparticle connectivity, limiting one-step processing into hierarchically porous structures. We overcome such challenges by using low-solid emulgel inks stabilized by chitin nanofibrils (nanochitin, NCh). By using complementary characterization platforms, we reveal NCh structuring into spatially controlled three-dimensional (3D) materials that generate multiscale porosities defined by emulsion droplet size, ice templating, and DIW infill density. The extrusion variables, key in the development of surface and mechanical features of printed architectures, are comprehensively analyzed by using molecular dynamics and other simulation approaches. The obtained scaffolds are shown for their hierarchical porous structures, high areal density, and surface stiffness, which lead to excellent modulation of cell adhesion, proliferation, and differentiation, as tested with mouse dermal fibroblast expressing green fluorescent proteins.Item Low Solids Emulsion Gels Based on Nanocellulose for 3D-Printing(2019-02-11) Huan, Siqi; Ajdary, Rubina; Bai, Long; Klar, Ville; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Department of Mechanical Engineering; Bio-based Colloids and MaterialsMultiphase (emulsion) gels with internal phase fractions between 0.1 and 0.5 were formulated at low loadings of cellulose nanofibrils (CNF), alginate, and polylactide (PLA). Their properties (rheology and morphology) fitted those of inks used for direct ink writing (DIW). The effect of formulation and composition variables were elucidated after printing cubic scaffolds and other solid designs. The distinctive microstructures that were developed allowed high printing fidelity and displayed limited shrinkage after room temperature and freeze-drying (0 and 5% shrinkage in the out-of-plane and in-plane directions upon freeze-drying, respectively). The CNF added in the continuous phase was shown to be critical to achieve rheology control as an effective interfacial stabilizer and to ensure the printability of the ink toward high structural reliability. We found that the extent of shape retention of the dried scaffolds resulted from the tightly locked internal structure. The PLA that was initially added in the nonpolar or organic phase (0 to 12%) was randomly embedded in the entire scaffold, providing a strong resistance to shrinkage during the slow water evaporation at ambient temperature. No surface collapse or lateral deformation of the dried scaffolds occurred, indicating that the incorporation of PLA limited drying-induced shape failure. It also reduced compression strain by providing better CNF skeletal support, improving the mechanical strength. Upon rewetting, the combination of the hydrophilicity imparted by CNF and alginate together with the highly porous structure of the 3D material and the internal microchannels contributed to high water absorption via capillary and other phenomena (swelling % between ∼400 and 900%). However, no shape changes occurred compared to the initial 3D-printed shape. The swelling of the scaffolds correlated inversely with the PLA content in the precursor emulsion gel, providing a means to regulate the interaction with water given its low surface energy. Overall, the results demonstrate that by compatibilization of the CNF-based hydrophilic and the PLA-based hydrophobic components, it is possible to achieve shape control and retention upon 3D printing, opening the possibility of adopting low-solids inks for DIW into dry objects. The dryable CNF-based 3D structural materials absorb water while being able to support load (high elastic modulus) and maintain the shape upon hydration.Item Multifunctional 3D-Printed Patches for Long-Term Drug Release Therapies after Myocardial Infarction(WILEY-VCH VERLAG, 2020-08-01) Ajdary, Rubina; Ezazi, Nazanin Zanjanizadeh; Correia, Alexandra; Kemell, Marianna; Huan, Siqi; Ruskoaho, Heikki J.; Hirvonen, Jouni; Santos, Hélder A.; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of Helsinki; University of British ColumbiaA biomaterial system incorporating nanocellulose, poly(glycerol sebacate), and polypyrrole is introduced for the treatment of myocardial infarction. Direct ink writing of the multicomponent aqueous suspensions allows multifunctional lattice structures that not only feature elasticity and electrical conductivity but enable cell growth. They are proposed as cardiac patches given their biocompatibility with H9c2 cardiomyoblasts, which attach extensively at the microstructural level, and induce their proliferation for 28 days. Two model drugs (3i-1000 and curcumin) are investigated for their integration in the patches, either by loading in the precursor suspension used for extrusion or by direct impregnation of the as-obtained, dry lattice. In studies of drug release conducted for five months, a slow in vitro degradation of the cardiac patches is observed, which prevents drug burst release and indicates their suitability for long-term therapy. The combination of biocompatibility, biodegradability, mechanical strength, flexibility, and electrical conductivity fulfills the requirement of the highly dynamic and functional electroresponsive cardiac tissue. Overall, the proposed cardiac patches are viable alternatives for the regeneration of myocardium after infarction through the effective integration of cardiac cells with the biomaterial.Item Nanochitin: Chemistry, Structure, Assembly, and Applications(AMERICAN CHEMICAL SOCIETY, 2022-07-13) Bai, Long; Liu, Liang; Esquivel, Marianelly; Tardy, Blaise L.; Huan, Siqi; Niu, Xun; Liu, Shouxin; Yang, Guihua; Fan, Yimin; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Nanjing Forestry University; National University of Costa Rica; Northeast Forestry University; University of British Columbia; Qilu University of TechnologyChitin, a fascinating biopolymer found in living organisms, fulfills current demands of availability, sustainability, biocompatibility, biodegradability, functionality, and renewability. A feature of chitin is its ability to structure into hierarchical assemblies, spanning the nano-and macroscales, imparting toughness and resistance (chemical, biological, among others) to multicomponent materials as well as adding adaptability, tunability, and versatility. Retaining the inherent structural characteristics of chitin and its colloidal features in dispersed media has been central to its use, considering it as a building block for the construction of emerging materials. Top-down chitin designs have been reported and differentiate from the traditional molecular-level, bottom-up synthesis and assembly for material development. Such topics are the focus of this Review, which also covers the origins and biological characteristics of chitin and their influence on the morphological and physical-chemical properties. We discuss recent achievements in the isolation, deconstruction, and fractionation of chitin nanostructures of varying axial aspects (nanofibrils and nanorods) along with methods for their modification and assembly into functional materials. We highlight the role of nanochitin in its native architecture and as a component of materials subjected to multiscale interactions, leading to highly dynamic and functional structures. We introduce the most recent advances in the applications of nanochitin-derived materials and industrialization efforts, following green manufacturing principles. Finally, we offer a critical perspective about the adoption of nanochitin in the context of advanced, sustainable materials.Item Oil-in-water Pickering emulsions via microfluidization with cellulose nanocrystals: 1. Formation and stability(ELSEVIER SCI LTD, 2019-11-01) Bai, Long; Lv, Shanshan; Xiang, Wenchao; Huan, Siqi; McClements, David Julian; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of Massachusetts BostonOil-in-water Pickering emulsions were successfully prepared via high-energy microfluidization using cellulose nanocrystals (CNC) as interfacial stabilizers. The influence of microfluidization pressure, CNC concentration, and oil type on droplet size and emulsion stability was determined. Under optimized homogenization conditions, CNC formed and stabilized emulsions based on corn, fish, sunflower, flax, orange, and MCT oils. The droplet size decreased with increasing microfluidization pressure from 9 to 17 kpsi, but then increased slightly at 19 kpsi. The creaming stability of the emulsions increased with CNC concentration, which was mainly attributed to the decrease in droplet size (mean particle diameter < 1 μm at CNC-to-oil ratios greater than 1:10) and slightly increased viscosity. The Pickering emulsions were stable to droplet coalescence, presumably due to strong electrostatic and steric repulsions between the lipid droplets carrying adsorbed nanoparticles. The Pickering emulsions had good stability over a range of environmental stresses: pH 3 to 10; NaCl ≤ 100 mM; temperature from 30 to 90 °C. Droplet flocculation was, however, observed under more acidic conditions (pH 2) and at high ionic strength (200–500 mM NaCl), owing to electrostatic screening. Our results indicate that microfluidization is an effective method for forming CNC-stabilized Pickering emulsions suitable for utilization in the food industry.Item Oil-in-water Pickering emulsions via microfluidization with cellulose nanocrystals: 2. In vitro lipid digestion(ELSEVIER SCI LTD, 2019-11-01) Bai, Long; Lv, Shanshan; Xiang, Wenchao; Huan, Siqi; McClements, David Julian; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of MassachusettsBio-based engineered nanomaterials are being explored for their utilization within foods to improve quality and enhance functionality. In this study, we investigated the impact of a naturally-derived particle stabilizer, cellulose nanocrystals (CNC), on the gastrointestinal fate and digestion of corn oil-in-water Pickering emulsions. A static 3-stage gastrointestinal tract (GIT) model was used to simulate the mouth, stomach and small intestine. The digestion of the CNC-coated lipid droplets was monitored by measuring the release of free fatty acids (FFAs) in the small intestine stage over time. The final extent of FFAs released was reduced by ∼40% by using emulsions containing 10 wt% of the dispersed phase, corn oil, stabilized with CNC (0.75 wt% of the aqueous phase). Three main mechanisms are proposed for this effect: (1) the irreversible adsorption of CNC to the lipid droplet surfaces inhibited bile salt and lipase adsorption; (2) coalescence and flocculation of the lipid droplets reduced the surface area available for the bile salts and lipase to bind; and (3) accumulation of FFAs at the surfaces of the lipid droplets inhibited lipolysis. Our findings suggest that CNC can be used as a food-grade particle stabilizer to modulate the digestion of Pickering emulsified lipids, which is useful for the development of given functional foods.Item Pickering Emulsions via Interfacial Nanoparticle Complexation of Oppositely Charged Nanopolysaccharides(AMERICAN CHEMICAL SOCIETY, 2021-03-17) Huan, Siqi; Zhu, Ya; Xu, Wenyang; McClements, David Julian; Bai, Long; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Materials Chemistry of Cellulose; University of Massachusetts Amherst; Northeast Forestry UniversityWe consider the variables relevant to adsorption of renewable nanoparticles and stabilization of multiphase systems, including the particle's hydrophilicity, electrostatic charge, axial aspect, and entanglement. Exploiting the complexation of two oppositely charged nanopolysaccharides, cellulose nanofibrils (CNFs) and nanochitin (NCh), we prepared CNF/NCh aqueous suspensions and identified the conditions for charge balance (turbidity and electrophoretic mobility titration). By adjusting the composition of CNF/NCh complexes, below and above net neutrality conditions, we produced sunflower oil-in-water Pickering emulsions with adjustable droplet diameters and stability against creaming and oiling-off. The adsorption of CNF/NCh complexes at the oil/water interface occurred with simultaneous partitioning (accumulation) of the CNF on the surface of the droplets in net negative or positive systems (below and above stochiometric charge balance relative to NCh). We further show that the morphology of the droplets and size distribution were preserved during storage for at least 6 months under ambient conditions. This long-term stability was held with a remarkable tolerance to changes in pH (e.g., 3-11) and ionic strength (e.g., 100-500 mM). The mechanism explaining these observations relates to the adsorption of the CNF in the complexes, counteracting the charge losses resulting from the deprotonation of NCh or charge screening. Overall, CNF/NCh complexes and the respective interfacial nanoparticle exchange greatly extend the conditions, favoring highly stable, green Pickering emulsions that offer potential in applications relevant to foodstuff, pharmaceutical, and cosmetic formulations.Item Recent Advances in Food Emulsions and Engineering Foodstuffs Using Plant-Based Nanocelluloses(Annual Reviews Inc., 2021-03-25) Bai, Long; Huan, Siqi; Zhu, Ya; Chu, Guang; McClements, David Julian; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of Massachusetts Amherst; Northeast Forestry UniversityIn this article, the application of nanocelluloses, especially cellulose nanofibrils and cellulose nanocrystals, as functional ingredients in foods is reviewed. These ingredients offer a sustainable and economic source of natural plant-based nanoparticles. Nanocelluloses are particularly suitable for altering the physicochemical, sensory, and nutritional properties of foods because of their ability to create novel structures. For instance, they can adsorb to air-water or oil-water interfaces and stabilize foams or emulsions, self-assemble in aqueous solutions to form gel networks, and act as fillers or fat replacers. The functionality of nanocelluloses can be extended by chemical functionalization of their surfaces or by using them in combination with other natural food ingredients, such as biosurfactants or biopolymers. As a result, it is possible to create stimuli-responsive, tailorable, and/or active functional biomaterials suitable for a range of foodapplications. In this article, we describe the chemistry, structure, and physicochemical properties of cellulose as well as their relevance for the application of nanocelluloses as functional ingredients in foods. Special emphasis is given to their use as particle stabilizers in Pickering emulsions, but we also discuss their potential application for creating innovative biomaterials with novel functional attributes, such as edible films and packaging. Finally, some of the challenges associated with using nanocelluloses in foods are critically evaluated, including their potential safety and consumer acceptance.Item Recent development in food emulsion stabilized by plant-based cellulose nanoparticles(Elsevier BV, 2021-12) Zhu, Mengqi; Huan, Siqi; Liu, Shouxin; Li, Zhiguo; He, Ming; Yang, Guihua; Liu, Shilin; McClements, David Julian; Rojas, Orlando J.; Bai, Long; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Northeast Forestry University; Qilu University of Technology; Huazhong Agricultural University; University of MassachusettsIn this review, we discuss the application of cellulose nanoparticles as a sustainable and cost-effective source of green stabilizers for formulation of foodstuff. Fibrillar cellulose nanocrystal and nanofibril stabilize Pickering systems because of their ability to adsorb at the oil/water interfaces, forming protective layers. They also form associative structures in the continuous phase, increasing their viscoelastic properties and preventing flocculation. We describe the chemical and structural features of nanocelluloses and discuss the principles that support their utilization as stabilizers, especially in the context of recent prospects in food and health domains, given safety and regulatory advances. In addition, we describe the benefits of combining nanocelluloses with other food ingredients to extend their functional attributes. Particularly, nanocellulose-based Pickering emulsions are used to create edible soft materials with multiple functionalities. This article is expected to stimulate the use of nanocelluloses as functional ingredients to create food products with improved performance and novel properties.Item Recent Innovations in Emulsion Science and Technology for Food Applications(AMERICAN CHEMICAL SOCIETY, 2021-08-18) Bai, Long; Huan, Siqi; Rojas, Orlando J.; McClements, David Julian; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of Massachusetts; Northeast Forestry UniversityEmulsion technology has been used for decades in the food industry to create a diverse range of products, including homogenized milk, creams, dips, dressings, sauces, desserts, and toppings. Recently, however, there have been important advances in emulsion science that are leading to new approaches to improving food quality and functionality. This article provides an overview of a number of these advanced emulsion technologies, including Pickering emulsions, high internal phase emulsions (HIPEs), nanoemulsions, and multiple emulsions. Pickering emulsions are stabilized by particle-based emulsifiers, which may be synthetic or natural, rather than conventional molecular emulsifiers. HIPEs are emulsions where the concentration of the disperse phase exceeds the close packing limit (usually >74%), which leads to novel textural properties and high resistance to gravitational separation. Nanoemulsions contain very small droplets (typically d < 200 nm), which leads to useful functional attributes, such as high optical clarity, resistance to gravitational separation and aggregation, rapid digestion, and high bioavailability. Multiple emulsions contain droplets that have smaller immiscible droplets inside them, which can be used for reduced-calorie, encapsulation, and delivery purposes. This new generation of advanced emulsions may lead to food and beverage products with improved quality, health, and sustainability.Item Self-Assembled Networks of Short and Long Chitin Nanoparticles for Oil/Water Interfacial Superstabilization(AMER CHEMICAL SOC, 2019-04-01) Bai, Long; Huan, Siqi; Xiang, Wenchao; Liu, Liang; Yang, Yang; Nugroho, Robertus Wahyu N.; Fan, Yimin; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of Helsinki; Nanjing Forestry UniversityHighly charged (zeta potential ζ = +105 mV, acetate counterions) chitin nanoparticles (NCh) of three different average aspect ratios (∼5, 25, and >60) were obtained by low-energy deconstruction of partially deacetylated chitin. The nanoparticles were effective in reducing the interfacial tension and stabilized the oil/water interface via network formation (interfacial dilatational rheology data) becoming effective in stabilizing Pickering systems, depending on NCh size, composition, and formulation variables. The improved interfacial wettability and electrosteric repulsion facilitated control over the nanoparticle's surface coverage on the oil droplets, their aspect ratio and stability against coalescence during long-term storage. Emulsion superstabilization (oil fractions below 0.5) occurred by the microstructuring and thickening effect of NCh that formed networks at concentrations as low as 0.0005 wt %. The ultrasound energy used during emulsion preparation simultaneously reduced the longer nanoparticles, producing very stable, fine oil droplets (diameter ∼1 μm). Our findings indicate that NCh surpasses any reported biobased nanoparticle, including nanocelluloses, for its ability to stabilize interfaces at ultralow concentrations and represent a step-forward in efforts to fully replace surfactants in multiphase systems.Item Thermally insulating and electroactive cellular nanocellulose composite cryogels from hybrid nanofiber networks(Elsevier Science, 2023-01-01) Hu, Yi; Cao, Meilian; Xu, Jianing; Liu, Xueying; Lu, Jiqing; Yan, Jie; Huan, Siqi; Han, Guangping; Bai, Long; Cheng, Wanli; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Northeast Forestry UniversityCellulose-based xerogels, cryogels and aerogels have been proposed to deliver the functions required by next-generation wearable electronics and energy materials. However, such systems often lack functionality and present limited mechanical resilience. Herein, we introduce a simple strategy to synthesize high-performance cryogels that combine cellulose and silica nanofibers that form ice-templated cellular architectures. Specifically, dual networks are produced by incorporating organic (cellulose) and inorganic (silica) nanofibers to form highly interconnected and vertically-aligned channels. Hence, ultralight structures (7.37 mg cm−3 in density and porosity of 99.37%) are produced with high mechanical strength, compressibility (dimensional recovery of up to 90%) and fatigue resistance (1000 loading cycles) along with low thermal conductivity (29.65 mW m−1K−1). Electrical responsiveness is supplemented by in situ polymerization of pyrrole, ensuing operation in a wide load range (0–18 kPa with sensitivity of 6.63 kPa−1 during > 1000 cycles). The obtained thermal insulating and electroactive materials are demonstrated for operation under extreme conditions (solvent and temperature). Overall, our dual network system provides a universal, multifunctional platform that can substitute state-of-the-art carbonized or carbon-based light-weight materials.Item Three-Dimensional Printed Cell Culture Model Based on Spherical Colloidal Lignin Particles and Cellulose Nanofibril-Alginate Hydrogel(AMERICAN CHEMICAL SOCIETY, 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; Department of Bioproducts and Biosystems; Department of Applied Physics; School services, CHEM; Bioproduct Chemistry; Biomolecular Materials; Bio-based Colloids and Materials; Biohybrid MaterialsThree-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.
