Anion Binding to Ammonium and Guanidinium Hosts: Implications for the Reverse Hofmeister Effects Induced by Lysine and Arginine Residues.

Anions have a profound effect on the properties of soluble proteins. Such Hofmeister effects have implications in biologics stability, protein aggregation, amyloidogenesis, and crystallization. However, the interplay between the important noncovalent interactions (NCIs) responsible for Hofmeister effects is poorly understood. To contribute to improving this state of affairs, we report on the NCIs between anions and ammonium and guanidinium hosts 1 and 2, and the consequences of these. Specifically, we investigate the properties of cavitands designed to mimic two prime residues for anion-protein NCIs─lysines and arginines─and the solubility consequences of complex formation. Thus, we report NMR and ITC affinity studies, X-ray analysis, MD simulations, and anion-induced critical precipitation concentrations. Our findings emphasize the multitude of NCIs that guanidiniums can form and how this repertoire qualitatively surpasses that of ammoniums. Additionally, our studies demonstrate the ease by which anions can dispense with a fraction of their hydration-shell waters, rearrange those that remain, and form direct NCIs with the hosts. This raises many questions concerning how solvent shell plasticity varies as a function of anion, how the energetics of this impact the different NCIs between anions and ammoniums/guanidiniums, and how this affects the aggregation of solutes at high anion concentrations.

Detection of Human Neutrophil Elastase by Fluorescent Peptide Sensors Conjugated to TEMPO-Oxidized Nanofibrillated Cellulose.

Peptide-cellulose conjugates designed for use as optical protease sensors have gained interest for point-of-care (POC) detection. Elevated serine protease levels are often found in patients with chronic illnesses, necessitating optimal biosensor design for POC assessment. Nanocellulose provides a platform for protease sensors as a transducer surface, and the employment of nanocellulose in this capacity combines its biocompatibility and high specific surface area properties to confer sensitive detection of dilute biomarkers. However, a basic understanding of the spatiotemporal relationships of the transducer surface and sensor disposition is needed to improve protease sensor design and development. Here, we examine a tripeptide, fluorogenic elastase biosensor attached to TEMPO-oxidized nanofibrillated cellulose via a polyethylene glycol linker. The synthetic conjugate was found to be active in the presence of human neutrophil elastase at levels comparable to other cellulose-based biosensors. Computational models examined the relationship of the sensor molecule to the transducer surface. The results illustrate differences in two crystallite transducer surfaces ((110) vs. (1-10)) and reveal preferred orientations of the sensor. Finally, a determination of the relative (110) vs. (1-10) orientations of crystals extracted from cotton demonstrates a preference for the (1-10) conformer. This model study potentiates the HNE sensor results for enhanced sensor activity design.

Assessment of Cellulose Nanofiber-Based Elastase Biosensors to Inflammatory Disease as a Function of Spacer Length and Fluorescence Response.

Inflammatory disease biomarker detection has become a high priority in point-of-care diagnostic research in relation to chronic wounds, with a variety of sensor-based designs becoming available. Herein, two primary aspects of biosensor design are examined: (1) assessment of a cellulose nanofiber (CNF) matrix derived from cotton ginning byproducts as a sensor transducer surface; and (2) assessment of the relation of spacer length and morphology between the CNF cellulose backbone and peptide fluorophore as a function of sensor activity for porcine pancreatic and human neutrophil elastases. X-ray crystallography, specific surface area, and pore size analyses confirmed the suitability of CNF as a matrix for wound care diagnostics. Based upon the normalized degree of substitution, a pegylated-linker connecting CNF transducer substrate to peptide fluorophore showed the greatest fluorescence response, compared to short- and long-chain alkylated linkers.

1,1',4,5-Tetra-hydro-tri-spiro-[1,3,2-di-aza-phosphole-2,2'-[1,3,5,2,4,6]tri-aza-triphosphinine-4',6''-dibenzo[d,f][1,3,2]dioxaphosphepine-6',6'''-dibenzo[d,f][1,3,2]dioxaphosphepine] acetone monosolvate.

The title compound, C26H22N5O4P3·C3H6O, has been achieved in a two-step synthesis that does not require chromatography. This mol-ecule contains a seven-membered spiro-cyclic ring at two P-atom positions and a five-membered ring containing new P-N bonds at the other P-atom position. Endocyclic torsion angles about the central biphenyl C-C bonds are -41.5 (3) and -44.4 (3)°, and P-N bonds of the central P3N3 ring are within the range 1.5665 (17)-1.6171 (17) Å, while the P-O distances are in the range 1.5940 (14)-1.6041 (14) Å. One N-H group makes an inter-molecular N-H⋯N hydrogen bond, forming centrosymmetric dimers, while the other N-H group makes an N-H⋯O hydrogen bond to the acetone solvent mol-ecule. The crystal was a two-component non-merohedral twin with ratio 0.811/0.189.

Silver Nanoparticle-Intercalated Cotton Fiber for Catalytic Degradation of Aqueous Organic Dyes for Water Pollution Mitigation.

Azo dyes are commonly used in textile color processing for their wide array of vibrant colors. However, in recent years these dyes have become of concern in wastewater management given their toxicity to humans and the environment. In the present work, researchers remediated water contaminated with azo dyes using silver nanoparticles (Ag NPs) intercalated within cotton fabric as a catalyst, for their enhanced durability and reusability, in a reductive degradation method. Three azo dyes­methyl orange (MO), Congo red (CR), and Chicago Sky Blue 6B (CSBB)­were investigated. The azo degradation was monitored by UV/vis spectroscopy, degradation capacity, and turnover frequency (TOF). The Ag NP−cotton catalyst exhibited excellent degradation capacity for the dyes, i.e., MO (96.4% in 30 min), CR (96.5% in 18.5 min), and CSBB (99.8% in 21 min), with TOFs of 0.046 min−1, 0.082 min−1, and 0.056 min−1, respectively, using a 400 mg loading of catalyst for 100 mL of 25 mg L−1 dye. To keep their high reusability while maintaining high catalytic efficiency of >95% degradation after 10 cycles, Ag NPs immobilized within cotton fabric have promising potential as eco-friendly bio-embedded catalysts.

Application of Lignin-Containing Cellulose Nanofibers and Cottonseed Protein Isolate for Improved Performance of Paper.

There is current interest in replacing petroleum-based additives in consumer paper products with abundantly available, renewable and sustainable biopolymers such as lignin-containing cellulose nanofibers (LCNFs) and cottonseed protein. This research characterized the performance of cottonseed protein isolate with/without LCNFs to increase the dry strength of filter paper. The application of 10% protein solution with 2% LCNFs as an additive improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Improvements in tensile modulus and tensile strength were greatest for samples containing larger amounts of lignin and a greater degree of polymerization than for those with less lignin from the same biomass sources.

Application of a novel boronated porphyrin (H2OCP) as a dual sensitizer for both PDT and BNCT.

BACKGROUND AND OBJECTIVE: Boronated porphyrins have emerged as promising dual sensitizers for use in both photodynamic therapy (PDT) and boron neutron capture therapy (BNCT), by virtue of their known tumor affinity, low cytotoxicity in dark conditions, and easy synthesis with high boron content. Octa-anionic 5,10,15,20-tetra[3,5-(nido-carboranylmethyl)phenyl] porphyrin (H2OCP) is a boronated porphyrin having eight boron clusters linked to the porphyrin ring. To evaluate H2OCP's applicability to both PDT and BNCT, we performed an in vitro and ex vivo study using F98 rat glioma cells. MATERIALS AND METHODS: We examined the time-dependent cellular uptake of H2OCP by measuring the boron concentration over time, and compared the cellular uptake/clearance of boron after exposure to H2OCP in conjunction with boronophenylalanine (BPA) and sodium borocaptate (BSH), both of which are currently used in clinical BNCT studies. We evaluated the cytotoxicity of H2OCP-mediated PDT using a colony-forming assay and assessed the tumorigenicity of the implantation of pre-treated cells using Kaplan-Meier survival curves. Fluorescence microscopy was also performed to evaluate the cellular uptake of H2OCP. RESULTS: H2OCP accumulated within cells to a greater extent than BPA/BSH, and H2OCP was retained inside the cells to approximately the same extent as BSH. The cell-surviving fraction following laser irradiation (8 J/cm², 18 hours after exposure to 10 µg B/ml H2OCP) was <0.05. The median survival times of the pre-treated cell-implanted rats were longer than those of the untreated group (P < 0.05). The fluorescence of H2OCP was clearly demonstrated within the tumor cells by fluorescence microscopy. CONCLUSIONS: H2OCP has been proven to be a promising photosensitizer for PDT. H2OCP has also been proposed as a potentially effective replacement of BPA or BSH, or as a replacement of both BPA/BSH. Our study provides more evidence that H2OCP could be an effective novel dual sensitizing agent for use in both PDT and BNCT.

Effect of Nanocellulose on the Properties of Cottonseed Protein Isolate as a Paper Strength Agent.

Currently, there is an increasing interest in the use of biopolymers in industrial applications to replace petroleum-based additives, since they are abundantly available, renewable and sustainable. Cottonseed protein is a biopolymer that, when used as a modifier, has shown improved performance for wood adhesives and paper products. Thus, it would be useful to explore the feasibility of using cellulose nanomaterials to further improve the performance of cottonseed protein as a paper strength agent. This research characterized the performance of cottonseed protein isolate with/without cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) to increase the dry strength of filter paper. An application of 10% protein solution with CNCs (10:1) or CNFs (50:1) improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Further analysis using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) indicated that the cottonseed protein/nanocellulose composites interacted with the filter paper fibers, imparting an increased dry strength.

Cellulose hydrolysis using ionic liquids and inorganic acids under dilute conditions: morphological comparison of nanocellulose.

The preparation of cellulose nanocrystals (CNCs) from cellulose extracted from cotton gin motes (CGM) using an ionic liquid (1-butyl-3-methylimidazolium chloride, [BMIm]Cl) under dilute conditions is reported. The concurrent process involves minimal swelling of cellulose with an ionic liquid and hydrolysis of the cellulose initiated by the addition of either phosphoric (H3PO4), hydrochloric (HCl), or sulfuric (H2SO4) acid. The obtained nanocrystals had similar physical properties (e.g. crystallinity) to the counterparts prepared under conventional conditions and exhibited superior thermal properties for sulfate CNCs. Additionally, the obtained CNCs had low surface functionalization, yet were colloidally stable for >90 days, which is a desirable trait for post-functionalization of CNCs. This process represents a general strategy utilizing dilute ionic liquids in the preparation of nanocellulose under mildly acidic conditions.

Alkali Hydrolysis of Sulfated Cellulose Nanocrystals: Optimization of Reaction Conditions and Tailored Surface Charge.

Cellulose nanocrystals (CNCs) are a biorenewable resource, which may be chemically modified to impart specific properties. Modified CNCs have found use in imaging applications, as rheology modifiers, polymer reinforcements, barrier and/or optical films, and nanocomposites. Nanoparticle dimensions of CNCs are typically 5-10 nm in width, with lengths of <100-300 nm. However, the physical properties are dependent upon the number and nature of the surface charge groups imparted during preparation. In the case of CNCs produced from sulfuric acid hydrolysis, the sulfated surface groups may be partially removed prior to further functionalization. This gives more available hydroxyls yet renders the CNCs less colloidally stable. Furthermore, conditions vary significantly and there is no consensus about the optimal conditions for partial removal of sulfate functionality or conditions developed to give specific surface charge. In the following, alkali hydrolysis of sulfate half-esters was quantified by conductometric titration of the strong acid groups, and using a design of experiments (DOE), optimal conditions were determined to produce CNCs with tailored surface charge.

A reinforced thermal barrier coat of a Na-tannic acid complex from the view of thermal kinetics.

The poor burning resistance of cotton necessitates the control of its pyrolytic reactions, but many approaches have relied on the use of synthetically engineered chemicals. Herein, we show how a natural polyphenol from plants-tannic acid-acts with sodium ions to create a robust thermal barrier coat on cotton, with a focus on thermal kinetics. The kinetic information, combined with thermal and spectral analyses, revealed that the outer layer of galloyl units in tannic acid decomposes via a two-step reaction, producing a multicellular char of crosslinked aromatic rings, followed by the blowing of carbonaceous cells into a further expanded structure. This intumescent function of tannic acid was found to be enhanced upon its complexation with sodium ions, which greatly increased the activation energy for the first step of the reaction of tannic acid, to promote the formation of a stable char. The resulting blown char coated the cotton fiber below the thermal decomposition temperature of cellulose and was sustained throughout the decomposition. The enhanced thermal barrier performance of the Na-tannic acid complex was demonstrated by the reduced heat release capacity of cotton, the value of which was only about one-third that of tannic acid itself, and the inhibition of flame generation on cotton.

Laboratory and Field Assessments of Erythritol Derivatives on the Survival, Reproductive Rate, and Control of Drosophila suzukii (Diptera: Drosophilidae).

Spotted-wing Drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a vinegar fly introduced unintentionally into the United States. Since 2008, D. suzukii has reduced annual berry yields from 6 to 100%. Effective control of D. suzukii during harvest requires weekly applications of low-residual, broad-spectrum insecticides that are unavailable for organic farming. A novel ingestible insecticide, a 4-carbon polyol, mesoerythritol (erythritol), was found to kill 75 to 100% of larval and adult D. suzukii. However, mesoerythritol, at effective concentrations (0.5-1.0M), may be cost-prohibitive. Therefore, we conducted laboratory tests to assess the effects of lower cost derivatives of erythritol, namely the pentaerythritol series of 1,3-diols on D. suzukii pupal production, adult production, adult mortality, brood output, and reproductive increase. We then selected the two most promising compounds for a field test on fruiting rabbiteye blueberry. From 90 to 100% of adults died when fed food moistened with 1M solutions of mesoerythritol and pentaerythritol. Mesoerythritol and dipentaerythritol at a concentration of 1M were ovicidal/larvicidal, killing ≥85% of immatures. Overall, 1M mesoerythritol killed 80% or more larvae and adults, thus bringing populations to near zero. The heaviest compound of this series, tripentaerythritol, at all concentrations, was largely benign to both adults and immatures. Thus, we cannot recommend tripentaerythritol for D. suzukii control. In a blueberry field, 0.5M mesoerythritol and 0.5M pentaerythritol, each by themselves, reduced egg infestation by 64% and larval infestation by 93%; their combination (0.25M mesoerythritol and 0.25M pentaerythritol) achieved even greater egg control with 82% fewer eggs infesting blueberry fruits.

Synthesis and in vitro properties of trimethylamine- and phosphonate-substituted carboranylporphyrins for application in BNCT.

A series of carboranylporphyrins containing either amine or phosphonic acid functionalities and two to six closo-carborane clusters have been synthesized via a [2+2] condensation of a dimethylamino- or diethylphosphonate-substituted dipyrromethane with a dicarboranylmethyl-benzaldehyde. The X-ray structures of four key reaction intermediates (1, 2, 3, and 4a) and of two target porphyrins, the diphosphonate ester- and the diamino-tetracarboranylporphyrins 5b and 6a, are presented and discussed. In vitro studies using human carcinoma HEp2 and human glioblastoma T98G cells show that these porphyrins are non-toxic in the dark up to 100 microM concentrations, and that a tetracarboranylporphyrin bearing two quaternary ammonium groups is the most efficiently taken up by cells at short times (up to 8 h), followed by a dicarboranylporphyrin bearing three phosphonic acid substituents. All carboranylporphyrins delivered therapeutic amounts of boron to T98G cells and localized mainly within the cell lysosomes.

The application of ultrasound in the enzymatic hydrolysis of switchgrass.

In a series of experiments, untreated and ammonium hydroxide pretreated Klenow lowland variety switchgrasses are converted to reducing sugars using low-frequency (20 kHz) ultrasound and commercially available cellulase enzyme. Results from experiments using untreated and pretreated switchgrasses with and without ultrasound are presented and discussed. In untreated switchgrass experiments, the combination of ultrasound and enzymes resulted in an increase of 7.5% in reducing sugars compared to experiments using just enzymes. In experiments using ammonium hydroxide pretreated switchgrass, the combination of ultrasound and enzymes resulted in an increase of 9.3% in reducing sugars compared to experiments using just enzymes. Experimental evidence indicates that there is a synergistic effect from the combination of ultrasound and enzymes which lowers the diffusion-limiting barrier to enzyme/substrate binding and results in an increase in reaction rate. Scanning electron microscopic images provide evidence that ultrasound-induced pitting increases substrate surface area and affects reaction rate and yield.