Structure and properties of nanoparticles: DES-lignin-g-PNVCL coated aspirin by self-assembly.

This work was carried out in order to broaden the application field of lignin and improve its additional value. The degraded deep eutectic solvent lignin-grafted poly(N-vinyl caprolactam) (DES-lignin-g-PNVCL) was synthesized by using modified DES-lignin and NVCL via activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP). Aspirin was coated with DES-lignin-g-PNVCL through self-assembly by an ethanol/water anti-solvent method to obtain lignin thermosensitive polymer nanoparticle coated aspirin (aspirin@LTNP). X-ray electron spectroscopy (XPS), elemental analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and ultraviolet visible spectroscopy (UV) were used to characterize the composition, structure and morphology of DES-lignin-g-PNVCL and aspirin@LTNP. The releasing behavior of aspirin@LTNP at different temperatures and pH values was investigated. The safety was evaluated by cytotoxicity tests. The results indicated that aspirin@LTNP was mainly accumulated by the hydrophobic effect and π-π interaction in the process of self-assembly, and its morphology was an ellipsoid stacked layer by layer. The aspirin@LTNP hydrophilic chains were increased and had externally hydrophilic and internally hydrophobic structures. The particle size decreased slightly during the self-assembly process. The red-shift occurred at the π-π interaction wavelength of the lignin aromatic ring, which indicated a physical coating process. The coating rate of aspirin@LTNP was 88.87%. Aspirin@LTNP showed an obvious temperature response; the 96 h cumulative release rate at the LCST was 73.75 ± 1.16%, while the 96 h cumulative release rate above the LCST was 28.10 ± 0.92%. The 96 h cumulative release rate was 63.21 ± 0.57% at pH = 1.5 and 49.56 ± 0.48% at pH = 7.4. The dosage of aspirin@LTNP used in the experiment was safe. This study provided a strategy for drug coating and controlled release.

Versatile Strategy for the Preparation of Woody Biochar with Oxygen-Rich Groups and Enhanced Porosity for Highly Efficient Cr(VI) Removal.

Biochar is widely used to remove hexavalent chromium [Cr(VI)] from wastewater through adsorption, which is recognized as a facile, cost-efficient, and high-selectivity approach. In this study, a versatile strategy that combines delignification with subsequent carbonization and KOH activation is proposed to prepare a novel woody biochar from waste poplar sawdust. By virtue of the unique multilayered and honeycomb porous structure induced by delignification and activation processes, the resultant activated carbonized delignified wood (ACDW) exhibits a high specific surface area of 970.52 m2 g-1 with increasing meso- and micropores and abundant oxygen-containing functional groups. As a benign adsorbent for the uptake of Cr(VI) in wastewater, ACDW delivers a remarkable adsorption capacity of 294.86 mg g-1 in maximum, which is significantly superior to that of unmodified counterparts and other reported biochars. Besides, the adsorption behaviors fit better with the Langmuir isotherm, the pseudo-second-order kinetic model, and the adsorption diffusion model in batch experiments. Based on the results, we put forward the conceivable adsorption mechanism that the synergistic contributions of the capillary force, electrostatic attraction, chemical complexation, and reduction action facilitate the Cr(VI) capture by ACDW.

Facile preparation of oxygen-rich porous polymer microspheres from lignin-derived phenols for selective CO2 adsorption and iodine vapor capture.

Lignin is a natural O-containing aromatic amorphous polymers from the residues of biorefinery and industrial papermaking, it can derive lots of aromatic phenol chemicals used as industrial raw materials by an efficient depolymerization, and then produce synthetic polymers. Here, we selected six aromatic units from the liquid products of lignin depolymerization, and tried to prepare diversified O-rich hyper-cross-linked polymers (HCPs) by one-pot Friedel-Crafts alkylation reaction for CO2 and iodine vapor capture. HCP1, HCP2, and HCP3 microspheres possessed similar porous structure with Brunauer-Emmett-Teller (BET) surface areas (SBET) of 14.1-20.6 m2/g and high O content (26.34-30.68 wt%), while HCP4, HCP5, and HCP6 were composed of many bulks with 3D networks structure, and showed larger SBET of 15.4-246.9 m2/g and relatively low O content (18.48-26.38 wt%). The results indicated that the chemical position and quantities of substituent groups (methoxy and alkyl) into lignin-derived units had evident impact on their morphology and textural parameters. These HCPs exhibited considerable CO2 uptake (64.1 mg/g) and selectivity (35.2) at 273 K， and high iodine vapor uptake (192.3 wt%). Moreover, the performance analysis implied that the SBET and pore volume of these HCPs had not played the dominated roles in the CO2 and I2 adsorption, while their pore size distribution, O-functional groups, and electron density will be more important for the capture of the both. This study will offer a facile synthesis of O-rich polymer microsphere adsorbents based on the green and sustainable lignin.

Preparation of LCST regulable DES-lignin-g-PNVCL thermo-responsive polymer by ARGET-ATRP.

To expand the field of high-value utilization of lignin. The degraded deep eutectic solvent lignin-grafted poly (N-Vinyl caprolactam) (DES-lignin-g-PNVCL) was synthesized by modified DES-lignin and NVCL via the combination of activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP). Fourier transform infrared spectroscopy (FT-IR), 1H NMR, X-ray electron spectroscopy (XPS), dynamic light scattering (DLS), differential scanning calorimeter (DSC) were used to characterize the structure and performance of DES-lignin-g-PNVCL. The results indicated that the PNVCL and DES-lignin-g-PNVCL were successfully prepared by ARGET-ATRP. The lowest critical solution temperature (LCST) of PNVCL was 35.75 °C. Due to different strength of hydrogen bond, different energies were required, so the LCST of the polymer can be regulated. When the molar ratio of phenolic hydroxyl group in degraded DES-lignin to 2-bromoisobutyryl bromide (BiBB) was increased from 1:1 to 1:7, the grafting rate of DES-lignin-Br was increased from 32.87% to 60.84%, and the LCST of DES-lignin-g-PNVCL was decreased from 47.98 °C to 27.88 °C. The LCST of DES-lignin-g-PNVCL was increased from 30.98 °C to 44.64 °C when the addition amount of DES-lignin-Br was increased from 20 mg to 200 mg. The LCST of DES-lignin-g-PNVCL was increased from 27.20 °C to 39.86 °C when the ratio of DMF/water was increased from 1:4 to 4:1. The LCST of DES-lignin-g-PNVCL was decreased from 52.10 °C to 31.02 °C when the concentration of DES-lignin-g-PNVCL was increased from 0.5 mg/mL to 2.5 mg/mL. The equation represented the relationship between LCST and influencing factors was obtained, the good predictability provided a tactics for preparing desired LCST thermo-responsible polymer.

Structure-Performance Correlations over Cu/ZnO Interface for Low-Temperature Methanol Synthesis from Syngas Containing CO2.

Cu/ZnO catalysts with varied Cu/(Cu + Zn) molar ratios were prepared by a facile solid-state method. The Cu/(Cu + Zn) molar ratio displayed a significant effect on the oxygen vacancy formation of the calcined catalysts, thereby influencing the CuO-ZnO interaction and the reducibility of CuO. The Cu/(Cu + Zn) molar ratio also exhibited a significant effect on Cu0 surface area, oxygen vacancy, the ratio of ZnO(002) plane to ZnO(100) plane, as well as the basicity and acidity of the reduced catalysts, thereby affecting the catalytic performance for low-temperature methanol synthesis from syngas containing CO2. The correlations of methanol space time yield (STY) versus the physicochemical characteristics of Cu/ZnO catalysts were studied. The catalyst with equal amounts of Cu and Zn displayed the best catalytic activity owing to higher Cu0 surface area, more oxygen vacancy and ZnO(002) plane, as well as more moderately basic sites.

Optimization of alkali-treated poplar fiber saccharification using metal ions and surfactants.

In this study, contrary to untreated poplar fiber, processing of alkali-treated poplar fiber was optimized for the enzymatic saccharification. Considering reducing sugar content as the evaluation index, pH, temperature, time, amount of enzyme, and rotational speed of shaker were standardized to optimize the sugar production by enzymatic hydrolysis. Using response surface methodology, the optimum technological condition of enzymatic hydrolysis was found to be utilizing 43 mg cellulase at 46 °C for 50 h. At this, the sugar conversion amount of NaOH or H2O2-NaOH pretreated poplar was 164.62 mg/g and 218.82 mg/g respectively. It was a corresponding increase of 446.73% or 626.75% than that of poplar fiber without a pretreatment. At a low concentration, metal ions and surfactants promoted the conversion of reducing sugar. Especially, 0.01 g/L Mn2+ and 0.50 g/L hexadecyl trimethyl ammonium bromide (CTAB) produced the best effect and increased the conversion rate of reducing sugar by 23.62% and 21.44% respectively. Also, the effect of the combination of metal ions and surfactants was better than that of a single accelerator. By improving the enzymatic process, these findings could enhance the utilization of poplar fiber for the production of reducing sugar.

Spinel-structure catalyst catalyzing CO2 hydrogenation to full spectrum alkenes with an ultra-high yield.

Spinel-like ZnFe2O4 is tailor-made synthesized for catalyzing CO2 hydrogenation, achieving an ultra-high yield (1858.1 g kgcat-1 h-1) of full spectrum alkenes in a three-stage reactor system. This study provides rational design concepts from catalyst to equipment amelioration by combining promoter regulation and ex situ water removal, efficiently catalyzing CO2 into valuable chemical feedstocks with industrial potential.

Selectable Microporous Carbons Derived from Poplar Wood by Three Preparation Routes for CO2 Capture.

Biomass-derived porous carbons are one kind of sustainable, extensive, and flexible carbon material for CO2 capture. Here, we prepared several microporous carbons from poplar wood by three preparation routes. Especially, the residues of the poplar wood after the bioethanol process were explored as precursors to prepare activated carbon by KOH and ZnCl2 activation. By the adjustment of the preparation routes and the optimization of the activation conditions, these porous carbons exhibited diversified morphology (sponge, nanosheets, and honeycomb structure), tunable porosity (specific surface areas: 511-2153 m2/g), and narrow micropore distribution (0.55-1.2 nm). These carbons had a high CO2 uptake of up to 217 mg/g at 273 K and 1 bar, which was comparable with those of many N-doped porous carbons, and possessed moderate isosteric heat of CO2 adsorption (21.1-43.2 kJ/mol), good cyclic ability, and high CO2/N2 selectivity (Henry's law: 44.0). The results indicated that CO2 uptake of these carbons was mainly decided by their micropore volume (d < 1.0 nm) at 273 K and 1 bar. This work provides an important reference for preparing promising CO2 adsorbents with tunable structures from similar biomass resources.

pH-Responsive Lignin-Based Nanomicelles for Oral Drug Delivery.

A pH-stimuli amphiphilic lignin-based copolymer was prepared, and it could self-assemble to form spherical nanomicelles with the addition of "switching" water. The morphology, structure, and physical properties of micelles were characterized with transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), particle-size analysis, and zeta-potential measurement. In vitro drug release exemplified that the micelles were pH-sensitive, retaining more than 84.36% ibuprofen (IBU) in simulated gastric fluid (pH 1.5) and presenting a smooth release of 81.81% IBU in simulated intestinal fluid (pH 7.4) within 72 h. Cell culture studies showed that the nanomicelles were biocompatible and boosted the proliferation of human bone marrow stromal cells hBMSC and mouse embryonic fibroblast cells NIH-3T3. Interestingly, the nanomicelles inhibited the survival of human colon cancer cells HT-29 with a final survival rate of only 5.34%. Therefore, this work suggests a novel strategy to synthesize intelligent lignin-based nanomicelles that show a great potential as oral drug carriers.

Assembly of lignin-based colloidal particles: effects of cationic surfactants, molecular weight, and solvent on morphology.

Sodium lignosulfonate (LS) is a lignin derivative, which has abundant resources and is an environmentally friendly raw material. In this study, cetyltrimethylammonium bromide (CTAB) and stearyltrimethylammonium bromide (STAB) were combined with LS at the isoelectric point for hydrophobic self-assembly. Transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and static contact angle data proved that LS/CTAB could form colloidal spheres, while LS/STAB could not form such spheres. The impact of the molecular weight of LS on the self-assembly of LS/CTAB was investigated by using the TEM, FTIR, and static contact angle data. The obtained results showed that LS/CTAB with 10 000-50 000 Da of LS could form colloidal spheres, while LS/CTAB with 3000-5000 Da of LS could not. In addition, the TEM images revealed that the solvent plays an important role in the morphology of LS/CTAB colloidal spheres. Finally, LS/CTAB colloidal spheres were used for the encapsulation of ibuprofen (IBU). The in vitro release behavior of IBU was proven to be pH-sensitive and exhibited controlled release properties. More than 85% IBU could be preserved in simulated gastric fluid, and over 75% could be released in simulated intestinal fluid. This work provides a theoretical basis for the preparation of LS/CTAB colloidal spheres and facilitates the expansion of its applications as a drug carrier.

Synthesis of water soluble quantum dots for monitoring carrier-DNA nanoparticles in plant cells.

Fluorescent quantum dots (QDs) have shown great promise for use as biolabels in cell and animal biology and more recently in plant sciences. An important use of QDs is for monitoring the dynamics, intracellular trafficking, and fate of carrier-DNA nanocomplexes in cell transfection and potentially in plant transformation. In this study, a low cost aqueous procedure has been developed to efficiently prepare biocompatible QDs for monitoring nanoparticle-mediated gene transfer in conjunction with molecular breeding of Jatropha curcas. Water-soluble CdSe nanoparticles were synthesized by self-assembly using L-Cysteine as stabilizer and optimal synthesis scheme established by fluorescence spectroscopy. The QDs were used to label chitosan-DNA nanoparticles via electrostatic interaction and the resultant QD-labeled chitosan-DNA complexes were shown to have superior fluorescence properties with red shift of emission and absorption spectra relative to the CdSe QDs alone. This system is being explored as a superior alternative to Agrobacterium-mediated genetic transformation of Jatropha curcas cells. PCR amplification of the full length of the carried reporter gene (GFP) suggests that the DNA was not digested in Jatropha curcas cells transfected with CdSe/CS-DNA complexes. Furthermore, GFP gene expression in the transfected callus cells, as evidenced by fluorescence detection, suggests that the target DNA was integrated into the plant genome.

Microbial dynamics in a sequencing batch reactor treating alkaline peroxide mechanical pulp and paper process wastewater.

BACKGROUND, AIM, AND SCOPE: For many years, highly concentrated wastewater generated from the pulp and paper industry has become the focus of much concern worldwide. The objectives of this study were to determine the treatment efficiency of the alkaline peroxide mechanical pulp (APMP) process wastewater using a sequencing batch reactor (SBR) and analyze the microbial dynamics of the wastewater treatment system using the random amplified polymorphic DNA (RAPD) method. MATERIALS AND METHODS: An SBR was applied to the treatment of APMP pulp and paper process wastewater. The wastewater characteristics and many physicochemical operator indicators in the wastewater treatment process were analyzed and determined according to standard methods. Microbial 16 S rDNA in active sludge was extracted, amplified, and analyzed using the RAPD method for the microbial dynamics of the wastewater treatment system. RESULTS AND DISCUSSION: Ten kinds of natural organic compounds of plants such as monoterpene were detected in the APMP pulp and paper process wastewater. With an influent chemical oxygen demand (COD) that varied in the range of 685.7 to 907.5 mg/L, the corresponding effluent COD was 176.5 to 266.1 mg/L and the removal efficiency was 70.3% to 79.8%. An optimal strain (S308: CAGGGGTGGA) was selected to study the population dynamics and diversity of the bacterial community. The RAPD-polymerase chain reaction (PCR) fingerprints showed very high polymorphism of the genetic bands (78-100%). Four groups of species were clustered using the unweighted pair group method with arithmetic (UPGMA) analysis, and the genetic distance was close between the species within each group. The Shannon-Weaver index was high and varied over time with the COD removal. CONCLUSIONS: The RAPD-PCR technique can be used to study microbial dynamics, which was shown to vary over time with the removal efficiency of SBR treating APMP pulp and paper process wastewater.

A sensitive fluorescence anisotropy method for the direct detection of cancer cells in whole blood based on aptamer-conjugated near-infrared fluorescent nanoparticles.

Based on the aptamer-conjugated core-shell near-infrared fluorescent nanoparticles (NIR-Nps) and fluorescence anisotropy measurement, the present study reported proof-of-principle for a rapid homogeneous assay approach that can detect target cancer cells without the need of the complicated separation steps in whole blood samples. Experimental investigation showed that the novel NIR-Nps have negligible background fluorescence and low inner filtration interference in complex biologic systems such as whole blood. The specific recognition characteristic of aptamer in whole blood samples was investigated by using the proposed fluorescence anisotropy method. The results showed that the fluorescent nanoparticle-tagged aptamer probes sequence could achieve specific recognition of the target cancer cells from complex mixtures including whole blood samples. And the reaction conditions for the binding between fluorescent nanoparticle-conjugated aptamer probes and target cancer cells were optimized. The present approach can exhibit sensitive and reproducible fluorescence anisotropy responses to the target cells concentration and the calibration curve showed good linearity when the target cells concentration is in the range from 4.0 x 10(3) to 7.0 x 10(5)cells/mL. Moreover, the present fluorescence anisotropy assay technique could be practically utilized for the detection of acute leukemia samples with improved capabilities and be comparable to the immunophenotyping methods clinically used.

[Development of nano-scale genic carriers in biomedicine].

Nano biotechnology is a developing field of science and technology in the 21st century. The emergence of nanomaterials provides a new way for gene carriers. This paper demonstrates the advantages and types of nano-scale genic carriers and the methods for introducing it into the body, and reviewed the application of nano-scale genic carriers in gene therapy and in breeding.

Optimization of metabolic pathways for bioconversion of lignocellulose to ethanol through genetic engineering.

The optimization of metabolic pathways is of fundamental importance for strategies aimed at improving the economics and yield of the lignocellulose-to-ethanol processes. Although Escherichia coli is capable of metabolizing a wide variety of substrates including hexoses and pentoses, its hexose metabolism is inferior to that of Zymomonas mobilis, an obligate, ethanologenic bacterium. We therefore inserted and expressed Z. mobilis genes encoding essential enzymes involved in the fermentation pathway, alcohol dehydrogenase II (adh II) and pyruvate decarboxylase (pdc), into E. coli, resulting in increased cell growth and ethanol production. Ethanol concentrations of >30 g/L were obtained on 10% glucose. Additionally, since pyruvate is mainly assimilated through pyruvate formate lyase (pfl) and forms formic acid and acetyl coenzyme A, metabolic redirection was attempted through gene knockout by Red-mediated recombination to decrease the byproducts of pyruvate metabolism. Under microaerobic conditions, pflA- and pflB-mutants produced more ethanol (163% and 207%, respectively) relative to the parent strain, using glucose as a carbon source.