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openaire: EC/FP7/291364/EU//MIMEFUN Controlled surface-initiated atom transfer radical polymerization (SI-ATRP) has previously been described as a versatile method that allows grafting polymer brushes on purely cellulosic forms of nanocelluloses, i.e., cellulose nanocrystal (CNC) nanorods and bacterial cellulose (BC) networks. However, corresponding SI-ATRP on long and entangled cellulose nanofibers (CNFs), having typically more complex composition and partly disordered structure, has been only little reported due to practical and synthetic challenges, in spite of technical need. In this work, the feasibility of SI-ATRP on CNFs is exemplified on the polymerization of poly(n-butyl acrylate) and poly(2-(dimethyl amino)ethyl methacrylate) brushes, both of which showed first order polymerization kinetics up to a chain length of ca. 800 repeat units. By constructing high and low initiator densities on CNF surfaces, we also show that, surprisingly, a higher grafting density of polymer brushes around CNF causes noticeable degradation of the CNF nanofibrillar backbone, whereas lower grafting densities retained the structural integrity of the CNF. We tentatively suggest that the side-chain brushes strain the disordered domains of CNF, causing degradation, which can be suppressed using a lower degree of substitution. Therefore, SI-ATRP of CNFs becomes subtler than that of, for example, CNCs, and careful balance has to be achieved between high density of brushes and excessive CNF degradation.

Hybrid nanocomposites were constructed based on colloidal nanofibrillar hydrogels with interpenetrating supramolecular hydrogels, displaying enhanced rheological yield strain and a synergistic improvement in storage modulus. The supramolecular hydrogel consists of naphthyl‐functionalized hydroxyethyl cellulose and a cationic polystyrene derivative decorated with methylviologen moieties, physically cross‐linked with cucurbit[8]uril macrocyclic hosts. Fast exchange kinetics within the supramolecular system are enabled by reversible cross‐linking through the binding of the naphthyl and viologen guests. The colloidal hydrogel consists of nanofibrillated cellulose that combines a mechanically strong nanofiber skeleton with a lateral fibrillar diameter of a few nanometers. The two networks interact through hydroxyethyl cellulose adsorption to the nanofibrillated cellulose surfaces. This work shows methods to bridge the length scales of molecular and colloidal hybrid hydrogels, resulting in synergy between reinforcement and dynamics.

Background: A 70-year-old male approximately 3 years after laparoscopic cholecystectomy presented to his primary care physician with a 4-month history of generalized malaise. Methods: A workup included magnetic resonance imaging that revealed a perihepatic abscess. The patient underwent ultrasound-guided drainage, with the removal of 1400 mL of purulent fluid and placement of 2 drains. Computed tomographic scanning showed resolution, and he was discharged home on oral antibiotics. At 2-month follow-up, the patient was asymptomatic, denying any constitutional symptoms. However, abdominal computed tomographic scanning revealed recurrence of the abscess, which measured approximately 18x9x7.5 cm, with mass effect on the liver. The patient was placed on intravenous antibiotics and scheduled for operative drainage. The abdomen was entered with a right subcostal incision, and 900 mL of purulent fluid was drained. We also noted abscess erosion through the inferolateral aspect of the right diaphragm into the pleural space. The pleural abscess was loculated and isolated from the lung parenchyma. Palpation within the abscess cavity revealed 9 large gallstones. Following copious irrigation and debridement of necrotic tissue, 3 drains were placed and the incision was closed. Results: The patient had an uneventful recovery and was discharged home on postoperative day number 6. Follow-up imaging at 3 months demonstrated resolution of the collection. Conclusion: Spillage of gallstones is a complication of laparoscopic cholecystectomy, occurring in 6% to 16% of all cases. Retained stones rarely result in a problem, but when complications arise, aggressive surgical intervention is usually necessary.

Surfaces capable of high-affinity binding of biomolecules are required in several biotechnological applications, such as purification, transfection, and sensing. Therein, the rod-shaped, colloidal cellulose nanocrystals (CNCs) are appealing due to their large surface area available for functionalization. In order to exploit electrostatic binding, their intrinsically anionic surfaces have to be cationized as biological supramolecules are predominantly anionic. Here we present a facile way to prepare cationic CNCs by surface-initiated atom-transfer radical polymerization of poly(N,N-dimethylaminoethyl methacrylate) and subsequent quaternization of the polymer pendant amino groups. The cationic polymer brush-modified CNCs maintained excellent dispersibility and colloidal stability in water and showed a ζ-potential of +38 mV. Dynamic light scattering and electron microscopy showed that the modified CNCs electrostatically bind cowpea chlorotic mottle virus and norovirus-like particles with high affinity. Addition of only a few weight percent of the modified CNCs in water dispersions sufficed to fully bind the virus capsids to form micrometer-sized assemblies. This enabled the concentration and extraction of the virus particles from solution by low-speed centrifugation. These results show the feasibility of the modified CNCs in virus binding and concentrating, and pave the way for their use as transduction enhancers for viral delivery applications. acceptedVersion