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Wood-derived nanofibrillated cellulose (NFC) has long been recognized as a valuable nanomaterial for food-related applications. However, the safety of NFC cannot be predicted just from the chemical nature of cellulose, and there is a need to establish the effect of the nanofibers on the gastrointestinal tract, to reassure the safe use of NFC in food-related products. The present work selected the intestinal cells Caco-2 and the gut bacteria Escherichia coli and Lactobacillus reuteri to evaluate the in vitro biological response to NFC. NFC materials with different surface modifications (carboxymethylation, hydroxypropyltrimethylammonium substitution, phosphorylation and sulfoethylation) and unmodified NFC were investigated. The materials were characterized in terms of surface functional group content, fiber morphology, zeta potential and degree of crystallinity. The Caco-2 cell response to the materials was evaluated by assessing metabolic activity and cell membrane integrity. The effects of the NFC materials on the model bacteria were evaluated by measuring bacterial growth (optical density at 600 nm) and by determining colony forming units counts after NFC exposure. Results showed no sign of cytotoxicity in Caco-2 cells exposed to the NFC materials, and NFC surface functionalization did not impact the cell response. Interestingly, a bacteriostatic effect on E. coli was observed while the materials did not affect the growth of L. reuteri . The present findings are foreseen to contribute to increase the knowledge about the potential oral toxicity of NFC and, in turn, add to the development of safe NFC-based food products.

Amorphous calcium phosphate (ACP) has shown significant effects on the biomineralization and promising applications in bio-medicine. However, the limited stability and porosity of ACP material restrict its practical applications. A storage stable highly porous ACP with Brunauer-Emmett-Teller surface area of over 400 m 2 /g was synthesized by introducing phosphoric acid to a methanol suspension containing amorphous calcium carbonate nanoparticles. Electron microscopy revealed that the porous ACP was constructed with aggregated ACP nanoparticles with dimensions of several nanometers. Large angle X-ray scattering revealed a short-range atomic order of <20 Å in the ACP nanoparticles. The synthesized ACP demonstrated long-term stability and did not crystallize even after storage for over 14 months in air. The stability of the ACP in water and an α-MEM cell culture medium were also examined. The stability of ACP could be tuned by adjusting its chemical composition. The ACP synthesized in this work was cytocompatible and acted as drug carriers for the bisphosphonate drug alendronate (AL) in vitro . AL-loaded ACP released ~25% of the loaded AL in the first 22 days. These properties make ACP a promising candidate material for potential application in biomedical fields such as drug delivery and bone healing.

The cross-coupling reaction of 1,3,5-triethynylbenzene with terephthaloyl chloride gives a novel ynone-linked porous organic polymer. Tethering alkyl amine species on the polymer induces chemisorption of CO 2 as revealed by the studies of ex situ infrared spectroscopy. By tuning the amine loading content on the polymer, relatively high CO 2 adsorption capacities, high CO 2 -over-N 2 selectivity, and moderate isosteric heat ( Q st ) of adsorption of CO 2 can be achieved. Such amine-modified polymers with balanced physisorption and chemisorption of CO 2 are ideal sorbents for post-combustion capture of CO 2 offering both high separation and high energy efficiencies.

Porous carbon materials with tunable porosities and functionalities represent an important class of CO₂ sorbents. The development of porous carbons from various types of biomass is a sustainable, economic and environmentally friendly strategy. Wood is a biodegradable, renewable, sustainable, naturally abundant and carbon-rich raw material. Given these advantages, the use of wood-based resources for the synthesis of functional porous carbons has attracted great interests. In this mini-review, we present the recent developments regarding sustainable porous carbons derived from wood-based biopolymers (cellulose, hemicelluloses and lignin) and their application in CO₂ capture.

We developed a novel biodetection method for influenza virus based on AC magnetic susceptibility measurement techniques (the DynoMag induction technique) together with functionalized multi-core magnetic nanoparticles. The sample consisting of an incubated mixture of magnetic nanoparticles and rolling circle amplified DNA coils is injected into a tube by a peristaltic pump. The sample is moved as a plug to the two well-balanced detection coils and the dynamic magnetic moment in each position is read over a range of excitation frequencies. The time for making a complete frequency sweep over the relaxation peak is about 5 minutes (10 Hz⁻10 kHz with 20 data points). The obtained standard deviation of the magnetic signal at the relaxation frequency (around 100 Hz) is equal to about 10 -5 (volume susceptibility SI units), which is in the same range obtained with the DynoMag system. The limit of detection with this method is found to be in the range of 1 pM.

A Ca 2+ -crosslinked wood-based nanofibrillated cellulose (NFC) hydrogel was investigated to build knowledge toward the use of nanocellulose for topical drug delivery applications in a chronic wound healing context. Proteins of varying size and isoelectric point were loaded into the hydrogel in a simple soaking procedure. The release of the proteins from the hydrogel was monitored and kinetics determining parameters of the release processes were assessed. The integrity of the hydrogel and proteins were also studied. The results showed that electrostatic interactions between the proteins and the negatively-charged NFC hydrogel structure played a central role in the loading process. The release of the proteins were governed by Fickian diffusion. An increased protein size, as well as a positive protein charge facilitated a slower and more sustained release process from the hydrogel matrix. At the same time, the positively-charged protein was shown to increase the post-loading hydrogel strength. Released proteins maintained structural stability and activity, thus indicating that the Ca 2+ -crosslinked NFC hydrogel could function as a carrier of therapeutic proteins without compromising protein function. It is foreseen that, by utilizing tunable charge properties of the NFC hydrogel, release profiles can be tailored to meet very specific treatment needs.