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The nonproductive adsorption of cellulase onto lignin significantly inhibited the enzymatic hydrolysis of lignocellulosic biomass. In this study, we constructed a rapid fluorescence detection (RFD) system, and using this system, we demonstrated that the addition of cationic additives DTAB or polyDADMAC greatly increased the partition coefficients of cellulose/lignin, reduced nonproductive adsorption, and enhanced the hydrolysis efficiency of lignocellulose compared to those of Tweens or PEGs. Moreover, the addition of polyDADMAC and DTAB increased the glucose yield released from the mixture of Avicel and AICS-lignin (MCL) by 16.9 and 20.6%, respectively, and reduced the inhibition rate of lignin by 16.9 and 20.7%, respectively. Interestingly, polyDADMAC or DTAB treatment performed more effectively for the enzymatic hydrolysis of pretreated lignocellulosic biomass, compared with MCL. We confirmed that the reduced hydrophobicity and increased zeta potential of lignin cocontribute to the dampening nonproductive adsorption of lignin. In particular, the zeta potential values of lignin and the partition coefficients of Avicel/lignin with the addition of additives showed a good correlation, suggesting that electrostatic force also plays a crucial role in the adsorbing of cellulase on lignin. This work will be conducive to decreasing the nonproductive binding of cellulase onto lignin and enhancing cellulose conversion.

We designed three types of hollow-shaped porous silica materials via a three-step biotemplate-directed method: porous hollow silica nanorods, hollow dendritic fibrous nanostructured silica (DFNS), and ultraporous sponge-like DFNS. The first step was making a biotemplate, for which we used cellulose nanocrystals (CNCs), consisting of rod-shaped nanoparticles synthesized by conventional acid hydrolysis of cellulose fibers. In a second step, core-shell samples were prepared using CNC particles as hard template by two procedures. In the first one, core-shell CNC-silica nanoparticles were synthesized by a polycondensation reaction, which exclusively took place at the surface of the CNCs. In the second procedure, a typical synthesis of DFNS was conducted in a bicontinuous microemulsion with the assistance of additives. DFNS was assembled on the surface of the CNCs, giving rise to core-shell CNC-DFNS structures. Finally, all of the silica-coated CNC composites were calcined, during which the CNC was removed from the core and hollow structures were formed. These materials are very lightweight and highly porous. All three structures were tested as nanocarriers for drug delivery and absorbents for dye removal applications. Dye removal results showed that they can adsorb methylene blue efficiently, with ultraporous sponge-like DFNS showing the highest adsorption capacity, followed by hollow DFNS and hollow silica nanorods. Furthermore, breast cancer cells show a lower cell viability when exposed to doxorubicin-loaded hollow silica nanorods compared with control or doxorubicin cultures, suggesting that the loaded nanorod has a greater anticancer effect than free doxorubicin.

Holey graphene (HG) features universal applications in adsorption because of the large surface areas and the abundant active sites across the nanopores, but it is difficult to produce HG nanosheets straightforwardly from bulk graphite with current etching methods. Herein, for the first time, we developed a one-step sonication-assisted liquid-phase exfoliation/etching method to produce HG nanosheets from bulk graphite by taking advantage of chitosan for stabilization. With the cavitation bubble collapse stress during the intense sonication, the graphite powders were exfoliated and nanopores of tunable diameters from 40 to 200 nm were generated across the graphene nanosheets. Importantly, with chitosan as the stabilizing agent to reduce the fluid collapse stress transferred onto the graphene nanosheets, the lateral size of HG could be as large as 30 μm. Using this approach, several holey layered crystals (graphite, hexagonal boron nitride, and tungsten disulfide) were fabricated with adequate nanostructures, including lateral size, nanosheet thickness, and nanopore size. Notably, the nanoporous structure endowed the graphene nanosheets with superior high double-stranded DNA adsorption (1253 μg/mg, the highest until now) and excellent DNA protection capacity. Based on this, the HG nanosheets were developed for the surface-mediated reversal gene transfection, displaying appreciable efficiency with the traditional methods.

Efficient selective separation of oils or organic pollutants from water is important for ecological, environmental conservation and sustainable development. Various absorption methods have emerged; the majority of them still suffer from defects including low removal efficiency, a complicated preparation process, and high cost. Herein, we present a highly porous and mechanical resilient bacterial cellulose (BC) carbon aerogel directly from BC hydrogel via facile directional freeze-drying and high-temperature carbonization. The resultant BC carbon aerogel showed excellent mechanical compressibility (maximal height compression ∼99.5%) and elastic recovery due to the porous structure. Taking advantages of the high thermal stability and superhydrophobicity, the BC carbon aerogel was directly used as a versatile adsorbent for oil/water separation. The result demonstrated that the BC carbon aerogel showed super oil/water separation selectivity with the oil absorption capacity as high as 132-274 g g -1 . More importantly, the BC carbon aerogel adsorbent can be reused by a simple absorption/combustion method and still keep high-efficiency oil absorption capacity and excellent superhydrophobicity after 20 absorption/combustion cycles, displaying recyclability and robust stability. In sum, the BC carbon aerogel introduced here is easy to fabricate, ecofriendly, highly scalable, low cost, mechanically robust, and reusable; all of these features make it highly attractive for oil/water separation application.

Self-assembly of nanoparticles (NPs) to form structural colors offers promising opportunities for developing electronic, optoelectronic, and magnetic devices. In this regard, we reported co-assembly of cellulose nanofibrils (CNFs) and graphene to produce colored thin films. We demonstrated that biomimetic iridescent "peacock feather"-like full-color thin films can be generated by simple evaporation of aqueous suspensions on a surface tension confined, optically symmetric indium tin oxide-coated polyethylene terephthalate substrate. Amphiphilic CNFs serve dual functions to attract hydrophobic graphene via van der Waals interactions and to disperse hydrophilically and anionically CNF-tethered graphene while regulating surface tension to induce capillary and Marangoni flows in the force fields and construct thickness variation during dewetting. These CNF-graphene thin films exhibit full-color patterns and function as tunable light and moisture actuators. This approach has high potential to be applied to assemble other metal or metal oxide NPs for fast, simple, and robust fabrication without involving any complex lithography and external fields.

Three-dimensional scaffolds (3D) with controlled shape, dual porosity and long-term mechanical and dimensional stability in biofluids are of interest as biotemplates in tissue engineering. Herein, self-standing and lightweight cellulose-based biogenic scaffolds with a spatially structured morphology, macropores and interconnected micropores were fabricated using a combination of direct ink writing 3D printing and freeze-drying techniques. This was achieved by developing a water-based and low-cost bicomponent ink based on commercially available nanofibrillated cellulose (NFC) and carboxymethyl cellulose (CMC). Physical cross-linking through dehydrothermal treatment significantly increased the surface hardness, indentation modulus, compression strength, as well as the dimensional stability of the scaffolds in biofluids, in comparison to untreated materials. However, no differences in the spectra of solid state nuclear magnetic resonance or infrared were observed for dehydrothermal treated samples, suggesting that the increase of mechanical properties and dimensional stability is based on the physical cross-linking of functional groups both at the interface between NFC and CMC. The supramolecular structure of the polymers was well-preserved as disclosed by X-ray diffraction measurements. The cross-linked scaffolds showed high proliferation, viability, and attachment of human bone tissue derived osteoblast cells (hFOB). The simple and straightforward avenue proposed here for the design of cellulose-based fibrous inks and dual porous scaffolds from the commercially available materials and without the need of any additional cross-linkers should pave the way for the development of implantable, degradable scaffolds and cell-laden biomaterials for bone tissue regeneration and 3D bioprinting applications.

The nanosilver-based antibacterial composite film used as food packaging has a potential hazard of silver leakage into the human body. In this study, hyperbranched polyamide-amine (HPAMAM) was used as a template, reducing agent, and stabilizer to synthesize Ag nanoparticles (Ag NPs) in situ, and then HPAMAM anchored Ag NPs onto oxidized cellulose to construct a regenerated cellulose film with a low silver leakage for antibacterial food packaging. Alkali hydroxide/urea solution was used to dissolve cotton fibers, and the hydroxyl groups at C-2 and C-3 of the glucose residues were oxidized to two aldehyde groups by NaIO 4 . Then, HPAMAM/Ag NPs composites (Ag@HPAMAM NPs) were grafted on the oxidized cellulose by the reaction between aldehyde groups and amino groups. The Ag@HPAMAM NPs-embedded cellulose films were achieved by regenerating the dissolved cellulose with ethanol and drying naturally. With a low silver leakage (<10%), Ag@HPAMAM NPs-embedded cellulose films exhibited a strong antibacterial effect on Escherichia coli and Staphylococcus aureus and effectively extended the storage life of cherry tomatoes as food packaging. In addition, the physical properties of Ag@HPAMAM NPs-embedded cellulose films were improved due to the anchor of Ag NPs onto oxidized cellulose by HPAMAM. This study provides a strategy for synthesizing Ag@HPAMAM NPs-embedded cellulose film, which has the potential to be used as a biodegradable, renewable, and safe antibacterial food package material.

The limitations in the transport of oxygen, nutrients, and metabolic waste products pose a challenge to the development of bioengineered bone of clinically relevant size. This paper reports the design and characterization of hierarchical macro/microporous scaffolds made of poly(lactic-co-glycolic) acid and nanohydroxyapatite (PLGA/nHA). These scaffolds were produced by combining additive manufacturing (AM) and thermally induced phase separation (TIPS) techniques. Macrochannels with diameters of ~300 μm, ~380 μm, and ~460 μm were generated by embedding porous 3D-plotted polyethylene glycol (PEG) inside PLGA/nHA/1,4-dioxane or PLGA/1,4-dioxane solutions, followed by PEG extraction using deionized (DI) water. We have used an I-optimal design of experiments (DoE) and the response surface analysis (JMP® software) to relate three responses (scaffold thickness, porosity, and modulus) to the four experimental factors affecting the scaffold macro/microstructures ( e.g ., PEG strand diameter, PLGA concentration, nHA content, and TIPS temperature). Our results indicated that a PEG strand diameter of ~380 μm, a PLGA concentration of ~10% w/v, a nHA content of ~10% w/w, and a TIPS temperature around -10°C could generate scaffolds with a porosity of ~90% and a modulus exceeding 4 MPa. This paper presents the steps for the I-optimal design of these scaffolds and reports on their macro/microstructures, characterized using scanning electron microscopy (SEM) and micro-computed tomography (micro-CT)., Competing Interests: Conflict of Interest Disclosure The authors declare no competing financial interest.

Requirements for safe, stable, and long-acting sunscreens are successfully accomplished by natural lignin due to its broad-spectrum ultraviolet (UV)-blocking and synergistic properties. Chemical sunscreens are encapsulated in enzymatic hydrolysis lignin (EHL) by a one-step high-intensity ultrasound method. Chemical sunscreen/EHL microcapsules were formed with 3 min processing, and the product could be stored without leaking for more than a whole year. Adding H 2 O 2 increased the cross-linking degree of EHL on the surface of the capsules. When 5 wt % alkyl polyglucoside (APG) was added as surfactant, the size of capsules dramatically decreased to ∼100 nm and the ratio of EHL and chemical sunscreen reached 1:1, which significantly enhanced UV-blocking ability of the composites. Compared to the creams containing chemical sunscreen/EHL microcapsules and free chemical sunscreen, the sun protection factor (SPF) of the cream containing the same amount of chemical sunscreen/EHL nanocapsules increased 85% and 195%, respectively. The cream containing 10 wt % of UVA and UVB type chemical sunscreen coencapsulated nanocapsules gave SPF 408. Due to antiphotolysis protection of EHL, the SPF of the creams increased initially and was maintained for more than 8 h under UV radiation. There was no obvious leaking or permeation of chemical sunscreens from the capsules. The EHL-based capsules showed good biocompatibility.

This work describes an all-biomass fluorescent hydrogel fabricated by functionalizing alginate (ALg) and cellulose nanofibers (CNF) hydrogels with fluorescent biomass carbon dots (CQDs) derived from glucose, xylose, and glucosamine. The biomass CQDs played dual functions in the composite hydrogels: first, endowing hydrogels with good fluorescent characters; second, enhancing the mechanical properties of hydrogels because of the cross-linking effect of the abundant oxygen-containing groups or amino groups on surface with ALg or CNF. The elastic modulus of ALg hydrogel and CNF hydrogel was increased by 4.7 times and 1.5 times, respectively, by the adding CQDs. As a proof of concept, ALg/CQDs-3 hydrogel and CNF/CQDs-3 hydrogel were used to detect Fe 3+ ions and gold nanoparticle (AuNPs) in aqueous solution, showing high sensitivity. The prepared all-biomass fluorescent hydrogels hold great potential in biological imaging, biosensing, and biological monitoring fields.