Facile preparation of cellulose/lignosulfonate derivatives composite films with high UV-shielding and gas barrier properties.

Herein, a serial of full cellulose and lignosulfonate derivatives (LS), including sodium lignosulfonate (LSS), calcium lignosulfonate (LSC), lignosulfonic acid (LSA), composite films were generated through dissolving cellulose in reversible carbon dioxide (CO2) ionic liquids solvent system (TMG/EG/DMSO/CO2 solvent system), followed by a facile solution-gelation transition and absorption strategy. The findings indicated that LS aggregated and embedded inside the cellulose matrix via H-bond interaction. The cellulose/LS derivatives composite films showed good mechanical properties which the tensile strength reaches the maximum value of 94.7 MPa in MCC3LSS film. While for the MCC1LSS film, the breaking strain increases to 11.6 %. The outstanding UV shielding effect and high transmittance in the visible region of composite films were also achieved and the shielding performance of the whole UV region (200-400 nm) tended to 100 % for MCC5LSS film. In addition, thiol-ene click reaction was selected as model reaction to verify the UV-shielding performance. It was also found that the oxygen and water vapor barrier performances of composite films were evidently associated with the intense H-bond interaction and tortuous path effect. The OP and WVP of MCC5LSS film were 0 and 6 × 10-3 g·µm/m2·day·kPa, respectively. These outstanding properties make them with great potential for packaging field.

The synthesis of multifunctional cellulose graft alternating copolymers of 3,4-dihydrocoumarin and epoxides in DBU/DMSO/CO2 solvent system.

Cellulose graft copolymers having well-defined structures could incorporate the characteristics of both the cellulose skeleton and side chains, providing a new method for the preparation functionalised cellulose derivatives. Herein, a series of multifunctional cellulose grafted, alternating 3,4-dihydrocoumarin (DHC) and epoxide (EPO) copolymers (cell-g-P(DHC-alt-EPO)) were prepared in a metal-free DBU/DMSO/CO2 solvent system without adding additional catalyst. Four examples of cell-g-P(DHC-alt-EPO) with tunable thermal and optical properties were synthesized by copolymerization of DHC with styrene oxide (SO), propylene oxide (PO), cyclohexene oxide (CHO) or furfuryl glycidyl ether (FGE) onto cellulose. The nonconjugated cell-g-P(DHC-alt-EPO) showed UV absorption properties with the maximum absorption peak at 282 nm and 295 nm and photoluminescence performance. A clustering-triggered emission mechanism was confirmed and consistent with DFT theoretical calculations. In DMSO solution, the copolymer (DHCSO5) with DP of 11.64 showed ACQ behaviour as the concentration increased. In addition, DHCSO5 had good antioxidant capacity with an instantaneous radical scavenging activity of 2,2-diphenyl-1-picrylhydrazine (DPPH) up to 65 % at a concentration of 40 mg/ ml and increased to 100 % after 30 min. Thus, the multifunctional cell-g-P(DHC-alt-EPO) materials had a variety of potential applications in the fields of fluorescent printing, bio-imaging, UV- shielding and antioxidants.

Engineering chitosan into fully bio-sourced, water-soluble and enhanced antibacterial poly(aprotic/protic ionic liquid)s packaging membrane.

The design and facile preparation of water-soluble and eco-friendly polymer packaging membrane materials is a fascinating research topic, particularly in terms of the increasing concerns on potential microplastics pollution in ecosystem. In this study, taking advantages of the structural features of chitosan (CS) and betaine hydrochloride (BHC), fully bio-sourced and water-soluble poly(aprotic/protic ionic liquid)s (PAPILs) were successfully designed and prepared through the reaction of the amino groups in CS and carboxyl groups in BHC. The structure and thermo-properties of the PAPILs were elucidated by a series of characteristic methods. The rheological properties of the PAPILs aqueous solutions were also investigated. Moreover, water-soluble PAPILs membrane with a smooth surface morphology and a tensile strength of 62.9 MPa was successfully prepared. The PAPILs membrane also exhibited satisfactory biocompatibility, excellent antibacterial activities and high oxygen barrier property. Together with these outstanding material performance and functionality, as a "proof of concept", the potential use of the PAPILs membrane as water-soluble packaging material for laundry detergent capsule and pesticide was preliminarily demonstrated. These findings provide significant insights for the design of sustainable and functional packaging materials by using natural resources.

Carboxylcellulose hydrogel confined-Fe3O4 nanoparticles catalyst for Fenton-like degradation of Rhodamine B.

Facile preparation of functional hydrogel materials for environmental catalysis is a hot research topic of soft materials science and green catalysis. In this study, a carboxylcellulose hydrogel confined Fe3O4 nanoparticles composite catalyst (Fe3O4@CHC) with magnetic recyclability has been synthesized by taking the advantages of the newly developed cellulose solution in tetramethyl guanidine/DMSO/CO2 through in situ acylation using mixed cyclic anhydrides and ion exchange reaction. The achieved Fe3O4@CHC hydrogel catalyst was shown to be an more efficient and better Fenton-like catalyst for decomposition of the organic dye rhodamine B (RhB) in the presence of hydrogen peroxide, with almost complete decomposition occurring within 180 min, in comparison with Fe3O4@cellulose hydrogel (CH) with excellent recyclability. This work provided a facile strategy for the preparation of hydrogel-based functional composite green catalytic materials, which has potential applications in green catalysis.

A standardized rat burr hole defect model to study maxillofacial bone regeneration.

With high incidence rate and unique regeneration features, maxillofacial burr hole bone defects require a specially designed bone defect animal model for the evaluation of related bone regenerative approaches. Although some burr hole defect models have been developed in long bones or calvarial bones, the mandible has unique tissue development origins and regenerative environments. This suggests that the defect model should be prepared in the maxillofacial bone area. After dissecting the anatomic structures of rat mandibles, we found that creating defects in the anterior tooth area avoided damaging important organs and improved animal welfare. Furthermore, the available bone volume at the anterior tooth area was superior to that of the posterior tooth and ascending ramus areas. We then managed to standardize the model by controlling the age, weight and gender of the animal, creating standardized measurement instruments and reducing the variations derived from various operators. We also succeeded in deterring the self-rehabilitation of the proposed model by increasing the defect size. The 6 × 2 mm and 8 × 2 mm defects were found to meet the requirements of bone regenerative studies. This study provided a step-by-step standardized burr hole bone defect model with minimal tissue damage in small animals. The evaluations resulting from this model testify to the in vitro outcomes of the proposed regenerative approaches and provide preliminary screening data for further large animal and clinical trials. Therefore, the inclusion of this model may optimize the evaluation systems for maxillofacial burr hole bone defect regenerative approaches. STATEMENT OF SIGNIFICANCE: Unremitting effort has been devoted to the development of bone regenerative materials to restore maxillofacial burr hole bone defects because of their high clinical incidence rate. In the development of these biomaterials, in vivo testing in small animals is necessary to evaluate the effects of candidate biomaterials. However, little has been done to develop such defect models in small animals. In this study, we developed a standardized rat mandible burr hole bone defect model with minimal injury to the animals. A detailed description and supplementary video were provided to guide the preparation. The development of this model optimizes the maxillofacial bone regenerative approach evaluation system.

Capturing CO2 to reversible ionic liquids for dissolution pretreatment of cellulose towards enhanced enzymatic hydrolysis.

To overcome the natural recalcitrance of cellulose for glucose production in aqueous media catalyzed by enzyme, in this study, a dissolution pretreatment strategy was developed by using in situ formed CO2-based reversible ionic compounds (RICs)/DMSO mixed organic electrolytes under mild conditions. The influences of the constitution of RICs, CO2 pressure, dissolution pretreatment time on the physic-chemical structure of cellulose were investigated systematically by FTIR, XRD, SEM, AFM towards in-depth understanding of the correlations between the pretreatment conditions, micro-scale structure and enzymatic saccharification of cellulose. The results showed that the tetramethyl guanidine (TMG) based RICs solvent system [TMGH]2+[O2COCH2CH2OCO2]2-/DMSO (XRICs = 0.1, XRICs: the mole fraction of the formed RICs in the mixture) presented the best performance, which was evidenced by 100% glucose yield after the dissolution-regeneration pretreatment strategy under mild conditions (T = 60 °C, Pco2 = 2.0 MPa, t = 2 h). Furthermore, the solvent system have good recyclability and usability.

Blood prefabricated hydroxyapatite/tricalcium phosphate induces ectopic vascularized bone formation via modulating the osteoimmune environment.

Successful bone healing depends significantly on the structure of blood clots and the functional responses of blood cells. Despite the importance of blood clots in osteogenesis, few studies have investigated the effects of blood clots during material-mediated bone regeneration. In this study, we implanted the bone graft substitute hydroxyapatite/tricalcium phosphate (HA/TCP) subcutaneously, with or without blood prefabrication, to evaluate the effects of blood clots on material-mediated bone formation. We observed that blood prefabricated HA/TCP induced ectopic vascularized bone-like structures, implying that blood prefabrication can induce a microenvironment sufficient for HA/TCP-mediated bone formation. The possible mechanisms were related to (1) modification of the fibrin network, which facilitates MSCs recruitment and differentiation, (2) modulation of the early osteoimmune environment with the upregulation of osteogenic factor BMP2, and (3) improved expression of VEGF and the enhancement of angiogenesis. These results demonstrate the multifaceted effects of blood clots in regulating osteogenesis, osteoclastogenesis, immune responses, and angiogenesis. Therefore, blood prefabrication can serve as a valuable strategy to improve the osteogenic capacity of materials, and prefabricating materials with blood clots prior to implantation should be encouraged. New generation bone substitute materials could target the modulation of a favorable blood clot response for improved bone regeneration.

Tuning surface properties of bone biomaterials to manipulate osteoblastic cell adhesion and the signaling pathways for the enhancement of early osseointegration.

Osteoblast cell adhesion is the initial step of early osseointegration responding to bone material implants. Enhancing the osteoblastic cell adhesion has become one of the prime aims when optimizing the surface properties of bone biomaterials. The traditional strategy focuses in improving the physical attachment of osteoblastic cells onto the surfaces of biomaterials. However, instead of a simple cell physical attachment, the osteoblastic cell adhesion has been revealed to be a sophisticated system. Despite the well-documented effect of bone biomaterial surface modifications on adhesion, few studies have focused on the underlying molecular mechanisms. Physicochemical signals from biomaterials can be transduced into intracellular signaling network and further initiate the early response cascade towards the implants, which includes cell survival, migration, proliferation, and differentiation. Adhesion is vital in determining the early osseointegration between host bone tissue and implanted bone biomaterials via regulating involving signaling pathways. Therefore, the modulation of early adhesion behavior should not simply target in physical attachment, but emphasize in the manipulation of downstream signaling pathways, to regulate early osseointegration. This review firstly summarized the basic biological principles of osteoblastic cell adhesion process and the activated downstream cell signaling pathways. The effects of different biomaterial physicochemical properties on osteoblastic cell adhesion were then reviewed. This review provided up-to-date research outcomes in the adhesion behavior of osteoblastic cells on bone biomaterials with different physicochemical properties. The strategy is optimised from traditionally focusing in physical cell adhesion to the proposed strategy that manipulating cell adhesion and the downstream signaling network for the enhancement of early osseointegration.

Fast dissolution pretreatment of the corn stover in gamma-valerolactone promoted by ionic liquids: Selective delignification and enhanced enzymatic saccharification.

The dissolution of corn stover was investigated in gamma-valerolactone (GVL) assisted by ionic liquids. An enhanced subsequent enzymatic saccharification was reached with a total reducing sugar yield of 0.69 g.g-1 and a glucose of 0.38 g.g-1 within 24 h. The treatment effects on the physical-chemical features of corn stover in terms of the natural recalcitrance to the subsequent biological digest were systematically investigated using composition analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The structures of the associated enzymatic hydrolysis lignin (EHL) and ionic liquid extracted lignin (IEL) were characterized by gel permeation chromatography (GPC), fourier transform infra-red spectroscopy (FTIR), phosphorous nuclear magnet resonance spectrometry (31P NMR), and heteronuclear single quantum coherence spectroscopy (HSQC) for an in-depth understanding of the delignification process and the basic structural information for further lignin valorization.

Steric hindrance colloidal microsphere approach to fabricate ordered and interconnected Pt or Pt/Ag hollow hemispheres.

A steric hindrance colloidal microspheres approach (SHCMA) has been developed for the fabrication of ordered Pt or Pt/Ag nanoparticles composite interconnected hollow hemispheres via colloidal lithography and physical vapor deposition. Monolayer ordered silica or silica/Ag nanoparticles composite microspheres partly embedded into the polydimethylsiloxane (PDMS) were used as template, and Pt was sputtered on it. Due to the PDMS stamp functionalized as a steric hindrance substrate, which guaranteed that the ordered silica or silica/Ag nanoparticles composite microspheres were only coated with Pt film on the sides that exposed in air. After removing the template particles, large area ordered interconnected Pt or Pt/Ag nanoparticles composite hollow hemispheres were generated. The fabricated Pt hollow hemispheres have flat bottoms and are flexible and robust enough to be easily folded. In addition to successfully solving the challenge about ordered structure construction of the hollow Pt or Pt/Ag nanoparticles composite hemispheres here, we also could finely control the wall thickness of these hemispheres easily by changing the sputtering time or current.