Deep oxidization of glucose driven by 4-acetamido-TEMPO for a glucose fuel cell at room temperature.

Exploiting suitable oxidation catalysts is of great importance in the development of sugar-based fuel cells (SFCs). Herein, a novel room-temperature glucose/O2 fuel cell (GFC), which employs 4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl (ACT) as an anodic electrocatalyst and air-breathing Pt-C as a cathode, is demonstrated. Under room temperature operation, the as-assembled GFCs are capable of delivering a maximum power density of 100 µW cm-2 in the presence of 50 mM glucose. Bulk electrolysis products of glucose identified by mass spectrum and Fourier transform infrared spectroscopy include gluconic acid and glucaric acid, suggesting that the aldehyde and primary hydroxy groups of glucose can be deeply oxidized into carboxyl groups through a 6e- pathway. The deep glucose oxidation capability makes ACT a promising anodic electrocatalyst for SFCs.

Glucaric acid additives for the antiplasticization of fibers wet spun from cellulose acetate/acetic acid/water.

Cellulose acetate (CA) receives notable attention as an environmentally friendly, biodegradable polymer from renewable, low-cost resources. CA polymers are believed to have a critical role in shaping a greener and more circular textile economy. However, the mechanical properties of CA fibers are among the lowest in terms of its tensile strength, poor wet strength, and low flexural strength. This study investigates the effect of biobased additives for antiplasticizing the mechanical performance and structure of CA fibers. At up to 5 % of CA, glucaric acid (GA) and its monoammonium salt were added to CA fibers. With 1.5 % GA additive, tensile modulus improved by 155%, tensile strength by 55 %, and CA flexibility according to knot to straight fiber tenacity ratios improved by 107 % when compared to neat CA fibers. Based on the results, green small molecule antiplasticizers do exist, but their performance improvements are observed at low percentages of loading.

PET Detection of Cerebral Necrosis Using an Infarct-Avid Agent 2-Deoxy-2-[18F]Fluoro-D-Glucaric Acid (FGA) in a Mouse Model of the Brain Stroke.

PURPOSE: Ischemic stroke is a leading cause of disability worldwide. The volume of necrotic core in affected tissue plays a major role in selecting stroke patients for thrombolytic therapy or endovascular thrombectomy. In this study, we investigated a recently reported positron emission tomography (PET) agent 2-deoxy-2-[18F]fluoro-D-glucaric acid (FGA) to determine necrotic core in a model of transient middle cerebral artery occlusion (t-MCAO) in mice. PROCEDURES: The radiopharmaceutical, FGA, was synthesized by controlled, rapid, and quantitative oxidation of clinical doses of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) in a one-step reaction using a premade kit. Brain stroke was induced in the left cerebral hemisphere of CD-1 mice by occluding the middle cerebral artery for 1 h, and then allowing reperfusion by removing the occlusion. One day post-ictus, perfusion single-photon emission tomography (SPECT) was performed with 99mTc-lableled hexamethylpropyleneamine oxime (HMPAO), followed by PET acquisition with FGA. Plasma and brain tissue homogenates were assayed for markers of inflammation and neurotrophins. RESULTS: The kit-based synthesis was able to convert up to 2.2 GBq of FDG into FGA within 5 min. PET images showed 375 % more accumulation of FGA in the ipsilateral hemisphere than in the contralateral hemisphere. SPECT images showed that the ipsilateral HMPAO accumulation was reduced to 55 % of normal levels; there was a significant negative correlation between the ipsilateral accumulation of FGA and HMAPO (p < 0.05). FGA accumulation in stroke also correlated with IL-6 levels in the ipsilateral hemisphere. There was no change in IL-6 or TNFα in the plasma of stroke mice. CONCLUSIONS: Accumulation of FGA correlated well with the perfusion defect and inflammatory injury. As a PET agent, FGA has potential to image infarcted core in the brain stroke injury with high sensitivity, resolution, and specificity.

Efficient electrochemical production of glucaric acid and H2 via glucose electrolysis.

Glucose electrolysis offers a prospect of value-added glucaric acid synthesis and energy-saving hydrogen production from the biomass-based platform molecules. Here we report that nanostructured NiFe oxide (NiFeOx) and nitride (NiFeNx) catalysts, synthesized from NiFe layered double hydroxide nanosheet arrays on three-dimensional Ni foams, demonstrate a high activity and selectivity towards anodic glucose oxidation. The electrolytic cell assembled with these two catalysts can deliver 100 mA cm-2 at 1.39 V. A faradaic efficiency of 87% and glucaric acid yield of 83% are obtained from the glucose electrolysis, which takes place via a guluronic acid pathway evidenced by in-situ infrared spectroscopy. A rigorous process model combined with a techno-economic analysis shows that the electrochemical reduction of glucose produces glucaric acid at a 54% lower cost than the current chemical approach. This work suggests that glucose electrolysis is an energy-saving and cost-effective approach for H2 production and biomass valorization.

Zirconia-supported rhenium oxide as an efficient catalyst for the synthesis of biomass-based adipic acid ester.

Synthesis of adipic acid, a key monomer of nylon-66 and polyurethane, from biomass is highly attractive for establishing green and sustainable chemical processes. Here, we report that zirconia-supported rhenium oxide (ReOx/ZrO2) efficiently catalyses the deoxydehydration of cellulose-derived d-glucaric acid, offering adipic acid ester with a yield of 82% by combining with a Pd/C catalyst in subsequent reactions.

Synthesized of glucose-responsive nanogels labeled with fluorescence molecule based on phenylboronic acid by RAFT polymerization.

We reported on the fabrication of sugar-responsive nanogels covalently incorporated with 3-acrylamidophenylboronic acid (AAPBA) as glucose-recognizing moiety, 2-(acrylamido)glucopyranose (AGA) as biocompatible moiety, and boron dipyrromethene (BODIPYMA) as fluorescence donor molecule. The p(AAPBA-AGA-BODIPYMA) nanogels were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization in the mixture solvents of H2O/ethanol. Nanogels could respond to glucose and size of nanogels increased after treating with 3 mg/mL glucose medium. The fluorescent intensity of nanogels varied dependent on different glucose concentrations. Besides, insulin, a model drug, can be encapsulated into nanogels with the loading amount up to 8.2%. The drug release was dependent on the content of AAPBA moieties in nanogels and glucose concentrations in release medium. The investigation on the cytotoxicity of nanogels revealed that nanogels had good compatibility. Such glucose-responsive nanogels have potential in detection and treatment of diabetes.

Mixed-mode liquid chromatography for the rapid analysis of biocatalytic glucaric acid reaction pathways.

Glucaric acid (GlucA) has been identified as one of the top 10 potential bio-based chemicals for replacement of oil-based chemicals. Several synthetic enzyme pathways have been engineered in bacteria and yeast to produce GlucA from glucose and myo-inositol. However, the yields and titres achieved with these systems remain too low for the requirements of a bio-based GlucA industry. A major limitation for the optimisation of GlucA production via synthetic enzymatic pathways are the laborious analytical procedures required to detect the final product (GlucA) and pathway intermediates. We have developed a novel method for the simple and simultaneous analysis of GlucA and pathway intermediates to address this limitation using mixed mode (MM) HILIC and weak anion exchange chromatography (WAX), referred to as MM HILIC/WAX, coupled with RID. Isocratic mobile phase conditions and the sample solvent were optimised for the separation of GlucA, glucose-1-phosphate (G1P), glucose-6-phosphate (G6P), inositol-1-phosphate (I1P), myo-inositol and glucuronic acid (GA). The method showed good repeatability, precision and excellent accuracy with detection and quantitation limits (LOD and LOQ) of 1.5-2 and 577 mM, respectively. The method developed was used for monitoring the enzymatic synthesis of the final step in the GlucA pathway, and showed that GlucA was produced from GA with near 100% conversion and a titre of 9.2 g L-1.

Catalytic Conversion of Biorenewable Sugar Feedstocks into Market Chemicals.

The transformation of low cost sugar feedstocks into market chemicals and monomers for existing or novel high performance polymers by chemical catalysis is reviewed. Emphasis is given to industrially relevant, continuous flow, trickle bed processes. Since long-term catalyst stability under hydrothermal conditions is an important issue to be addressed in liquid phase catalysis using carbohydrate feedstocks, we will primarily discuss the results of catalytic performance for prolonged times on stream. In particular, the selective aerobic oxidation of glucose to glucaric acid and the subsequent selective hydrogenation to adipic acid is reviewed. Hydroxymethylfurfural (HMF), which is readily available from fructose, can be upgraded by oxidation to furan dicarboxylic acid (FDCA) or by consecutive reduction and hydrogenolysis to hexanetriol (HTO) followed by hydrogenolysis to biobased hexanediol (HDO). Direct amination of HDO yields biobased hexamethylene diamine (HMDA). Aerobic oxidation of HDO represents an alternative route to biobased adipic acid. HMDA and adipic acid are the monomers required for the production of nylon- 6,6, a major polymer for engineering and fibre applications.

[Construction of a glucaric acid biosensor for screening myo-inositol oxygenase variants].

Glucaric acid (GA), a top value-added chemical from biomass, has been widely used for prevention and control of diseases and the production of polymer materials. In GA biosynthesis pathway, the conversion of inositol to glucuronic acid that catalyzed by myo-inositol oxygenase is the limiting step. It is necessary to improve MIOX activity. In the present study, we constructed a high-throughput screening system through combing the concentration of GA with the green fluorescent protein fluorescence intensity. By applying this screening system, three positive variants (K59V/R60A, R171S and D276A) screened from the mutant library. In comparison, the recombinant strain Escherichia coli BL21(DE3)/MU-R171S accumulated more GA, 136.5% of that of the parent strain.

HEMOLYMPH CHEMISTRY REFERENCE RANGES OF THE CHILEAN ROSE TARANTULA GRAMMOSTOLA ROSEA (WALKENAER, 1837) USING THE VETSCAN BIOCHEMISTRY ANALYZER BASED ON IFCC-CLSI C28-A3.

The use of invertebrate hemolymph chemistry analysis has the potential to become a major diagnostic tool. The goal of this study was to generate statistically sound hemolymph reference ranges from healthy tarantulas. Hemolymph was drawn from wild caught, acclimatized, and apparently healthy female Chilean rose tarantulas Grammostola rosea (Walkenaer, 1837) ( n = 43) using a modified technique. Hemolymph samples were separately analyzed using the Avian-Reptilian Profile Plus reagent rotor for VetScan® for the following chemistries: aspartate aminotransferase, bile acids, creatine kinase, uric acid, glucose, total calcium, phosphorus, total protein, albumin, potassium, and sodium. With this method the authors were able to establish statistically sound reference ranges for aspartate aminotransferase, creatine kinase, glucose, phosphorus, and total protein. Further in situ studies will determine the practical usability of these values in the evaluation of tarantula health.

Imaging of isoproterenol-induced myocardial injury with 18F labeled fluoroglucaric acid in a rat model.

Positron emission tomography (PET) of myocardial infarction (MI) by infarct avid imaging has the potential to reduce the time to diagnosis and improve diagnostic accuracy. The objective of this work was to synthesize 18F-labeled glucaric acid (FGA) for PET imaging of isoproterenol-induced cardiomyopathy in a rat model. METHODS: We synthesized 18F-FGA by controlled oxidation of 18F-fluorodeoxy glucose (FDG), mediated by 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) in presence of NaBr and NaOCl in highly-buffered reaction conditions. After ascertaining preferential uptake of 18F-FGA in necrotic as compared to normal H9c2 myoblasts, the biodistribution and circulation kinetics of 18F-FGA was assessed in mice. Moreover, the potential of 18F-FGA to image myocardial damage was investigated in a rat model of isoproterenol-induced cardiomyopathy. Isoproterenol-induced myocardial injury was verified at necropsy by tissue staining and plasma cardiac troponin levels. RESULTS: Synthesis of radiochemically pure 18F-FGA was accomplished by a 5 min, one step oxidation of 18F-FDG. Reaction yield was quantitative and no side-products were detected. Biodistribution studies showed rapid elimination from the body (ke = 0.83 h-1); the major organ of 18F-FGA accumulation was kidney. In the rat model, isoproterenol-treatment resulted in significant increase in cardiac troponin. PET images showed that the hearts of isoproterenol-treated rats accumulated significant amounts of 18F-FGA, whereas healthy hearts showed negligible uptake of 18F-FGA. Target-to-nontarget contrast for 18F-FGA accumulation became significantly more pronounced in 4 h images as compared to images acquired 1 h post-injection. CONCLUSION: 18F-FGA can be easily and quantitatively synthesized from ubiquitously available 18F-FDG as a precursor. The resultant 18F-FGA has a potential to serve as an infarct-avid agent for PET imaging of MI. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: 18F-FGA/PET will complement existing perfusion imaging protocols in therapeutic decision making, determination of revascularization candidacy and success, differentiation of ischemia from necrosis in MI, discrimination of myocarditis from infarction, and surveillance of heart transplant rejection.

A robust and easily reproducible protocol for the determination of size and size distribution of iron sucrose using dynamic light scattering.

Iron sucrose (IS), a nanocolloidal solution used in the treatment of iron deficiency anemia, is currently under investigation for the elucidation of its critical quality attributes. Assessment of IS's size and size distribution has been recently attempted using dynamic light scattering (DLS). However, due to heterogeneous interpretation of DLS data, variable results were retrieved. The aim of this work was to establish a simple and reproducible DLS protocol to unequivocally define the size and size distribution of IS by using size distribution approximation in Number. Underlining the limitations of the commonly used DLS approximations, we identified the drug as being composed of a population of monodisperse nanoparticles of about 7 nm in diameter. The method here described might therefore be useful for the evaluation of quality, safety and efficacy of IS and its follow-on versions.

Iron sucrose: assessing the similarity between the originator drug and its intended copies.

Iron sucrose (IS) is a complex nanocolloidal intravenous suspension used in the treatment of iron-deficiency anemia. Follow-on IS products (iron sucrose similars (ISSs)) have obtained marketing authorization by the generic pathway, implying that identical copies of IS may be manufactured. However, recent prospective and retrospective clinical studies showed discrepancies in clinical outcomes, which might be related to differences in physicochemical properties. The aim of this work is to measure and compare the physicochemical properties of IS and three ISSs available in the market using innovative analytical procedures. The comprehensive elucidation of size, size distribution, morphology, and stability of these complex drugs revealed very significant differences between the products. This study serves to provide the basis to define critical quality attributes that may be linked to differences in clinical outcome and thus may contribute to an adequate regulatory approach for IS and its follow-on products.

Human mesenchymal stem cell-derived iron oxide exosomes allow targeted ablation of tumor cells via magnetic hyperthermia.

Magnetic hyperthermia, or the heating of tissues using magnetic materials, is a promising approach for treating cancer. We found that human mesenchymal stem cells (MSCs) isolated from various tissues and MSCs expressing the yeast cytosine deaminase∷uracil phosphoribosyl transferase suicide fusion gene (yCD∷UPRT) can be labeled with Venofer, an iron oxide carbohydrate nanoparticle. Venofer labeling did not affect cell proliferation or the ability to home to tumors. All Venofer-labeled MSCs released exosomes that contained iron oxide. Furthermore, these exosomes were efficiently endocytosed by tumor cells. Exosomes from Venofer-labeled MSCs expressing the yCD∷UPRT gene in the presence of the prodrug 5-fluorocytosine inhibited tumor growth in a dose-dependent fashion. The treated tumor cells were also effectively ablated following induction of hyperthermia using an external alternating magnetic field. Cumulatively, we found that magnetic nanoparticles packaged into MSC exosomes are efficiently endocytosed by tumor cells, facilitating targeted tumor cell ablation via magnetically induced hyperthermia.

Phenylpropanoid profiling reveals a class of hydroxycinnamoyl glucaric acid conjugates in Isatis tinctoria leaves.

The brassicaceous herb, Isatis tinctoria, is an ancient medicinal plant whose rosette leaf extracts have anti-inflammatory and anti-allergic activity. Brassicaceae are known to accumulate a variety of phenylpropanoids in their rosette leaves acting as antioxidants and a UV-B shield, and these compounds often have pharmacological potential. Nevertheless, knowledge about the phenylpropanoid content of I. tinctoria leaves remains limited to the characterization of a number of flavonoids. In this research, we profiled the methanol extracts of I. tinctoria fresh leaf extracts by liquid chromatography - mass spectrometry (LC-MS) and focused on the phenylpropanoid derivatives. We report the structural characterization of 99 compounds including 18 flavonoids, 21 mono- or oligolignols, 2 benzenoids, and a wide spectrum of 58 hydroxycinnamic acid esters. Besides the sinapate esters of malate, glucose and gentiobiose, which are typical of brassicaceous plants, these conjugates comprised a large variety of glucaric acid esters that have not previously been reported in plants. Feeding with 13C6-glucaric acid showed that glucaric acid is an acyl acceptor of an as yet unknown acyltransferase activity in I. tinctoria rosette leaves. The large amount of hydroxycinnamic acid derivatives changes radically our view of the woad metabolite profile and potentially contributes to the pharmacological activity of I. tinctoria leaf extracts.

Physicochemical Characterization of Iron Carbohydrate Colloid Drug Products.

Iron carbohydrate colloid drug products are intravenously administered to patients with chronic kidney disease for the treatment of iron deficiency anemia. Physicochemical characterization of iron colloids is critical to establish pharmaceutical equivalence between an innovator iron colloid product and generic version. The purpose of this review is to summarize literature-reported techniques for physicochemical characterization of iron carbohydrate colloid drug products. The mechanisms, reported testing results, and common technical pitfalls for individual characterization test are discussed. A better understanding of the physicochemical characterization techniques will facilitate generic iron carbohydrate colloid product development, accelerate products to market, and ensure iron carbohydrate colloid product quality.

Validation of a quantitative susceptibility mapping acquisition and reconstruction pipeline using a new iron sucrose based MR susceptibility phantom.

PURPOSE: Quantitative susceptibility mapping is a new technique and its processing pipeline has to be validated before clinical practice. We described an easy to build magnetic resonance (MR) susceptibility phantom based on iron sucrose. MATERIALS AND METHODS: In a plastic container, Eppendorf tubes containing increasing iron sucrose concentration ranging from 0 to 60µg Fe/mL were inserted in an agarose gel. To estimate susceptibility, multiple coronal gradient echo acquisitions were performed with varying angle of the phantom relative to the B0 field, ranging from 30 to 90°. Quantitative susceptibility maps were reconstructed using the l1 and l2 norm of total variation using Split Bregman approach. Iron concentration was finally estimated from the susceptibility in the tubes. RESULTS: In l1norm susceptibility and estimated iron concentration were not different from the real values while l2norm underestimated the susceptibility. A correlation was found between the angle of the phantom and the difference between real and estimated iron concentrations. The results highlight the importance of this validation by emphasizing the effects of various reconstruction parameters as well as acquisition conditions. Using optimal parameters, the quantitative susceptibility mapping provides a very good estimation of the iron concentrations in the phantom.

ML and ML2 complex formation between Ca(ii) and d-glucose derivatives in aqueous solutions.

The complex formation equilibria between Ca2+ ions and six carbohydrate derivatives related to d-glucose was quantitatively characterized by potentiometry, freezing point depression and polarimetry. Complexation could not be observed for d-glucose, while weak association was deduced for d-sorbitol and d-mannitol. Stronger complexes are formed with d-gluconate and d-heptagluconate due to the presence of the carboxylate group. In addition to the plausible 1 : 1 species, the 1 : 2 species can also be detected at higher ligand to metal ratios. The ML type complex is also formed with d-glucuronate and d-glucarate. The strong association for d-gluconate and d-heptagluconate was attested by freezing point depression measurements. Polarimetric results show that for these two ligands the specific rotation of the complexed and free anions is only slightly different. The stability of the 1 : 1 complexes follows the order: mannitol < sorbitol < glucuronate < heptagluconate ≈ gluconate < glucarate. The formation of the ML2 type species has been established for polyhydroxy ligands having at least one carboxylate group in addition to the conformational flexibility.

Production of Glucaric Acid from Hemicellulose Substrate by Rosettasome Enzyme Assemblies.

Hemicellulose biomass is a complex polymer with many different chemical constituents that can be utilized as industrial feedstocks. These molecules can be released from the polymer and transformed into value-added chemicals through multistep enzymatic pathways. Some bacteria produce cellulosomes which are assemblies composed of lignocellulolytic enzymes tethered to a large protein scaffold. Rosettasomes are artificial engineered ring scaffolds designed to mimic the bacterial cellulosome. Both cellulosomes and rosettasomes have been shown to facilitate much higher rates of biomass hydrolysis compared to the same enzymes free in solution. We investigated whether tethering enzymes involved in both biomass hydrolysis and oxidative transformation to glucaric acid onto a rosettasome scaffold would result in an analogous production enhancement in a combined hydrolysis and bioconversion metabolic pathway. Three different enzymes were used to hydrolyze birchwood hemicellulose and convert the substituents to glucaric acid, a top-12 DOE value added chemical feedstock derived from biomass. It was demonstrated that colocalizing the three different enzymes to the synthetic scaffold resulted in up to 40 % higher levels of product compared to uncomplexed enzymes.

Ferrous iron content of intravenous iron formulations.

The observed biological differences in safety and efficacy of intravenous (IV) iron formulations are attributable to physicochemical differences. In addition to differences in carbohydrate shell, polarographic signatures due to ferric iron [Fe(III)] and ferrous iron [Fe(II)] differ among IV iron formulations. Intravenous iron contains Fe(II) and releases labile iron in the circulation. Fe(II) generates toxic free radicals and reactive oxygen species and binds to bacterial siderophores and other in vivo sequestering agents. To evaluate whether differences in Fe(II) content may account for some observed biological differences between IV iron formulations, samples from multiple lots of various IV iron formulations were dissolved in 12 M concentrated HCl to dissociate and release all iron and then diluted with water to achieve 0.1 M HCl concentration. Fe(II) was then directly measured using ferrozine reagent and ultraviolet spectroscopy at 562 nm. Total iron content was measured by adding an excess of ascorbic acid to reduce Fe(III) to Fe(II), and Fe(II) was then measured by ferrozine assay. The Fe(II) concentration as a proportion of total iron content [Fe(III) + Fe(II)] in different lots of IV iron formulations was as follows: iron gluconate, 1.4 and 1.8 %; ferumoxytol, 0.26 %; ferric carboxymaltose, 1.4 %; iron dextran, 0.8 %; and iron sucrose, 10.2, 15.5, and 11.0 % (average, 12.2 %). The average Fe(II) content in iron sucrose was, therefore, ≥7.5-fold higher than in the other IV iron formulations. Further studies are needed to investigate the relationship between Fe(II) content and increased risk of oxidative stress and infections with iron sucrose.