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 Ca 2+ 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 Ca 2+ and Mg 2+ 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.

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The engineering of microbial systems increasingly strives to achieve a co-existence and co-functioning of different populations. By creating interactions, one can utilize combinations of cells where each population has a specialized function, such as regulation or sharing of metabolic burden. Here we describe a microfluidic system that enables long-term and independent growth of fixed and distinctly separate microbial populations, while allowing communication through a thin nano-cellulose filter. Using quorum-sensing signaling, we can couple the populations and show that this leads to a rapid and stable connection over long periods of time. We continue to show that this control over communication can be utilized to drive nonlinear responses. The coupling of separate populations, standardized interaction, and context-independent function lay the foundation for the construction of increasingly complex community-wide dynamic genetic regulatory mechanisms.

Microplastics accumulate in various aquatic organisms causing serious health issues, and have raised concerns about human health by entering our food chain. The recovery techniques for the most challenging colloidal fraction are limited, even for analytical purposes. Here we show how a hygroscopic nanocellulose network acts as an ideal capturing material even for the tiniest nanoplastic particles. We reveal that the entrapment of particles from aqueous environment is primarily a result of the network’s hygroscopic nature - a feature which is further intensified with the high surface area of nanocellulose. We broaden the understanding of the mechanism for particle capture by investigating the influence of pH and ionic strength on the adsorption behaviour. We determine the nanoplastic binding mechanisms using surface sensitive methods, and interpret the results with the random sequential adsorption (RSA) model. These findings hold potential for the explicit quantification of the colloidal nano- and microplastics from different aqueous environments, and eventually, provide solutions to collect them directly on-site where they are produced.

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