One-pot synthesis of folic acid modified carbonized polymer dots with red emittision for selective imaging of cancer cells.

Carbonized polymer dots (CPDs), as a novel fluorescent material, have broad application prospects in the fields of bio-imaging, bio-sensors, disease diagnosis and photovoltaic devices due to their low cost, low toxicity, easy modification and little environmental impact. In this paper, folic acid (FA) modified CPDs (FA-CPDs) are synthesized from p-Phenylenediamine (p-PD) and FA molecules using a traditional one pot hydrothermal reaction in order to detect cancer cells containing a folate receptor (FR). The synthesized FA-CPDs were characterized by transmission electron microscopy, Fourier transfrom infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, UV-vis and fluorescence techniques. The red fluorescence emission is realized by doping phosphorus atoms into the carbonized polymer. Upon excitation at 513 nm, the maximum emission wavelength of FA-CPDs aqueous solution was obtained at 613 nm. Moreover, the as-prepared FA-CPDs exhibit excellent excitation-independent behavior and good stability with high quantum yield (QY) at about 30.6%. The binding of FA-CPDs with FRs on cancer cells produces target recognition and enters the cells through endocytosis. Additionally, it is worth noting that FA-CPDs have good biocompatibility and imaging in HeLa cells has been successfully achieved. Therefore, our FA-CPDs have potential applications as biocompatibility probes for cancer diagnosis and treatment.

A innovative stepwise strategy using magnetic Fe3O4-co-graft tannin/polyethyleneimine composites in a coupled process of sulfate radical-advanced oxidation processes to control harmful algal blooms.

A novel co-graft tannin and polyethyleneimine co-coating magnetic composite (TP@Fe3O4) was prepared in the study. On this premise, an unique stepwise efficient strategy based on magnetic flocculation and Sulfate radical (SO4•-)-advanced oxidation processes (S-AOPs) for eliminating Microcystis aeruginosa (M. aeruginosa) and algal organic matters (AOMs) was presented. Due to the high positive charge of TP@Fe3O4, a > 99 % high algae removal rate was obtained at a modest TP@Fe3O4 dosage of 100 mg/L at pH = 8.0 with a short separation time of 5 min. Further, peroxymonosulfate (PMS) treatment was employed as a pre-oxidation method to lower cell stability and promote M. aeruginosa removal by subsequent TP@Fe3O4 flocculation. The PMS/TP@Fe3O4 system successfully cuts the optimum dose of TP@Fe3O4 in half (50 mg/L) without causing obvious cell damage. Following algal fast magnetic separation, ultraviolet (UV) was introduced to activate PMS to totally degrade AOM and microcystin. Response surface methodology (RSM) demonstrated that UV/PMS oxidation removed > 80 % of DOC and > 94 % of microcystin under optimal conditions. SO4•- was the main radical species that aided in the elimination of AOM. This is the first study to use magnetic flocculation in conjunction with AOPs to mitigate harmful algal blooms, which can enable the non-destructive eradication of M. aeruginosa while also efficiently degrading AOMs.

Stretchable and conductive cellulose hydrogel electrolytes for flexible and foldable solid-state supercapacitors.

In this study, the anti-freezing conductive hydrogel electrolytes with outstanding mechanical properties were synthesized by a facile and feasible method. The mechanical and anti-freezing properties of the synthesized polyacrylamide/lithium lhloride/water soluble cellulose acetate (PAM/LiCl/WSCA) hydrogels are significantly enhanced with the addition of WSCA and LiCl. The tensile strength and toughness of the gels were gradually increased to 341 KPa and 1.2 MJ/m3, respectively. The hydrogel electrolyte can remain soft and flexible at -80 °C, displaying certain elasticity and electrical conductivity. In addition, the super-capacitor assembled with PAM/LiCl/WSCA hydrogel as electrolyte showed excellent stability in capacitance retention after 500 times of folding cycles and 10,000 times of charge and discharge tests. The capacitor still maintains 64.64 % of its capacity at -40 °C. This facile strategy to fabricate anti-freezing conductive hydrogel electrolyte provides a new idea and way to the application of hydrogels as electrolytes in extreme cold environments.

[Mandibular secretory carcinoma: a case report].

Secretory carcinoma, a low-grade malignant tumor, occurs mainly in parotid, submandibular gland, and small salivary glands in the mouth. It has not yet been reported in the mandible. Now we report a case occurred in the right mandibular angle of secretory carcinoma, accompanying with its diagnosis, treatment and prognosis.

Skin-inspired cellulose conductive hydrogels with integrated self-healing, strain, and thermal sensitive performance.

In this study, a versatile cellulose conductive hydrogels with outstanding mechanical properties, rapid self-healing performance, and excellent thermal sensitivity were successfully fabricated. The tensile strength and toughness of the gels gradually increased to 249 kPa and 1.57 MJ/m3, respectively, and the healing efficiency of the hydrogels quickly reached 96.3% within 60 min. Importantly, the hydrogels exhibited a broad strain window (0-2066%) with a gauge factor ranging from 0.22 to 6.7, which could monitor of both obvious and subtle motion of the human body with high sensitivity and good repeatability. Moreover, the sensors also possessed good thermal sensitivity in the 0% and 400% state, and the response of the gel sensors increased from 8.3 to 87.9 when the temperature was increased from 35 to 85 °C. This study provides inspiration for the development of biocompatible and multifunctional cellulose-based wearable sensors with excellent mechanical, strain and temperature sensing and self-healing properties.

Structural and molecular dynamics studies of a C1-oxidizing lytic polysaccharide monooxygenase from Heterobasidion irregulare reveal amino acids important for substrate recognition.

Lytic polysaccharide monooxygenases (LPMOs) are a group of recently discovered enzymes that play important roles in the decomposition of recalcitrant polysaccharides. Here, we report the biochemical, structural, and computational characterization of an LPMO from the white-rot fungus Heterobasidion irregulare (HiLPMO9B). This enzyme oxidizes cellulose at the C1 carbon of glycosidic linkages. The crystal structure of HiLPMO9B was determined at 2.1 Å resolution using X-ray crystallography. Unlike the majority of the currently available C1-specific LPMO structures, the HiLPMO9B structure contains an extended L2 loop, connecting ß-strands ß2 and ß3 of the ß-sandwich structure. Molecular dynamics (MD) simulations suggest roles for both aromatic and acidic residues in the substrate binding of HiLPMO9B, with the main contribution from the residues located on the extended region of the L2 loop (Tyr20) and the LC loop (Asp205, Tyr207, and Glu210). Asp205 and Glu210 were found to be involved in the hydrogen bonding with the hydroxyl group of the C6 carbon of glucose moieties directly or via a water molecule. Two different binding orientations were observed over the course of the MD simulations. In each orientation, the active-site copper of this LPMO preferentially skewed toward the pyranose C1 of the glycosidic linkage over the targeted glycosidic bond. This study provides additional insight into cellulose binding by C1-specific LPMOs, giving a molecular-level picture of active site substrate interactions. DATABASE: The atomic coordinates and structure factors for HiLPMO9B have been deposited in the Protein Data Bank with accession code 5NNS.

Biochemical studies of two lytic polysaccharide monooxygenases from the white-rot fungus Heterobasidion irregulare and their roles in lignocellulose degradation.

Lytic polysaccharide monooxygenases (LPMO) are important redox enzymes produced by microorganisms for the degradation of recalcitrant natural polysaccharides. Heterobasidion irregulare is a white-rot phytopathogenic fungus that causes wood decay in conifers. The genome of this fungus encodes 10 putative Auxiliary Activity family 9 (AA9) LPMOs. We describe the first biochemical characterization of H. irregulare LPMOs through heterologous expression of two CBM-containing LPMOs from this fungus (HiLPMO9H, HiLPMO9I) in Pichia pastoris. The oxidization preferences and substrate specificities of these two enzymes were determined. The two LPMOs were shown to cleave different carbohydrate components of plant cell walls. HiLPMO9H was active on cellulose and oxidized the substrate at the C1 carbon of the pyranose ring at ß-1,4-glycosidic linkages, whereas HiLPMO9I cleaved cellulose with strict oxidization at the C4 carbon of glucose unit at internal bonds, and also showed activity against glucomannan. We propose that the two LPMOs play different roles in the plant-cell-wall degrading system of H. irregulare for degradation of softwood and that the lignocellulose degradation mediated by this white-rot fungus may require collective efforts from multi-types of LPMOs.

Integration of mild acid hydrolysis in γ-valerolactone/water system for enhancement of enzymatic saccharification from cotton stalk.

In this study, mild acid hydrolysis using γ-valerolactone (GVL)/water system integrated with enzymatic hydrolysis was carried out for the enhancement of enzymatic saccharification efficiency. The quantitative analysis of soluble carbohydrates and structural characterizations of solid residues were conducted. Results showed that the soluble carbohydrates in the water-phase were mainly composed of monomers and oligomers from xylose and glucose, while the contents of which were depended on the ratio of GVL to water. Moreover, the inhibitors were hardly detected due to the moderate pretreatment severity. Compared with the untreated feedstock, the yields of enzymatic hydrolysis from pretreated samples increased by two-fold with the mixture of 80/20 GVL/H2O. Combined with the amount of glucose (14.6%) dissolved in the water-phase, over 92.6% of glucose in cotton stalk was released and recovered. Based on the comprehensive analysis, treatment with GVL/H2O system provided us a more effective approach for sugar production from biomass.

Mind your P's and Q's: the coming of age of semiconducting polymer dots and semiconductor quantum dots in biological applications.

Semiconductor quantum dots (QDs) and semiconducting polymer nanoparticles (Pdots) are brightly emissive materials that offer many advantages for bioanalysis and bioimaging, and are complementary to revolutionary advances in fluorescence technology. Within the context of biological applications, this review compares the evolution and different stages of development of these two types of nanoparticle, and addresses current perceptions about QDs. Although neither material is a wholesale replacement for fluorescent dyes, recent trends have demonstrated that both types of nanoparticle can excel in applications that are often too demanding for fluorescent dyes alone. Examples discussed in this review include single particle tracking and imaging, multicolor imaging and multiplexed detection, biosensing, point-of-care diagnostics, in vivo imaging and drug delivery.

Comparison of physical properties of regenerated cellulose films fabricated with different cellulose feedstocks in ionic liquid.

With the serious "white pollution" resulted from the non-biodegradable plastic films, considerable attention has been directed toward the development of renewable and biodegradable cellulose-based film materials as substitutes of petroleum-derived materials. In this study, environmentally friendly cellulose films were successfully prepared using different celluloses (pine, cotton, bamboo, MCC) as raw materials and ionic liquid 1-ethyl-3-methylimidazolium acetate as a solvent. The SEM and AFM indicated that all cellulose films displayed a homogeneous and smooth surface. In addition, the FT-IR and XRD analysis showed the transition from cellulose I to II was occurred after the dissolution and regeneration process. Furthermore, the cellulose films prepared by cotton linters and pine possessed the most excellent thermal stability and mechanical properties, which were suggested by the highest onset temperature (285°C) and tensile stress (120 MPa), respectively. Their excellent properties of regenerated cellulose films are promising for applications in food packaging and medical materials.

Enzymatic saccharification of sugarcane bagasse by N-methylmorpholine-N-oxide-tolerant cellulase from a newly isolated Galactomyces sp. CCZU11-1.

Based on the enrichment culture strategy, a novel N-methylmorpholine-N-oxide (NMMO)-tolerant cellulase-producing strain Galactomyces sp. CCZU11-1 was isolated from soil samples. After the optimization of culture condition, the highest FPA (13.4 U/mL) and CMCase (24.5 U/mL) were obtained. In both culture and reaction media containing NMMO 25% (w/v), the cellulase from Galactomyces sp. CCZU11-1 still had good activity. Furthermore, high saccharification rate was obtained in aqueous-NMMO media. Moreover, the fermentability of the hydrolyzates, obtained after enzymatic in situ saccharification of the NMMO-pretreated sugarcane bagasse, was evaluated using Saccharomyce scerevisiae. In conclusion, Galactomyces sp. CCZU11-1 is a promising candidate as high NMMO-tolerant cellulase producer and has potential application in future.

The putative endoglucanase PcGH61D from Phanerochaete chrysosporium is a metal-dependent oxidative enzyme that cleaves cellulose.

Many fungi growing on plant biomass produce proteins currently classified as glycoside hydrolase family 61 (GH61), some of which are known to act synergistically with cellulases. In this study we show that PcGH61D, the gene product of an open reading frame in the genome of Phanerochaete chrysosporium, is an enzyme that cleaves cellulose using a metal-dependent oxidative mechanism that leads to generation of aldonic acids. The activity of this enzyme and its beneficial effect on the efficiency of classical cellulases are stimulated by the presence of electron donors. Experiments with reduced cellulose confirmed the oxidative nature of the reaction catalyzed by PcGH61D and indicated that the enzyme may be capable of penetrating into the substrate. Considering the abundance of GH61-encoding genes in fungi and genes encoding their functional bacterial homologues currently classified as carbohydrate binding modules family 33 (CBM33), this enzyme activity is likely to turn out as a major determinant of microbial biomass-degrading efficiency.