Effects of cold plasma pretreatment combined with sodium periodate on property enhancement of dialdehyde starch prepared using native maize starch.

This study represents the inaugural investigation into the effect of cold plasma (CP) pretreatment combined with sodium periodate on the preparation of dialdehyde starch (DAS) from native maize starch and its consequent effects on the properties of DAS. The findings indicate that the maize starch underwent etching by the plasma, leading to an increase in the particle size of the starch, which in turn weakened the rigid structure of the starch and reduced its crystallinity. Concurrently, the plasma treatment induced cleavage of the starch molecular chain, resulting in a decrease in the viscosity of the starch and an enhancement of its fluidity. These alterations facilitated an increased contact area between the starch and the oxidising agent sodium periodate, thereby augmenting the efficiency of the DAS preparation reaction. Consequently, the aldehyde group content was elevated by 9.98 % compared to the conventional DAS preparation methodology. Therefore, CP could be an efficient and environmentally friendly non-thermal processing method to assist starch oxidation for DAS preparation and property enhancement.

Periodate oxidation of nanofibrillated cellulose films for active packaging applications.

An alternative packaging material based on cellulose that possesses excellent barrier properties and is potentially useful for active packaging has been developed. Cellulose nanofibril was efficiently and selectively oxidized with sodium periodate generating reactive aldehyde groups. These groups formed hemiacetal and hemialdal bonds during film formation and, consequently, highly transparent, elastic and strong films were created even under moisture saturation conditions. The periodate oxidation treatment additionally decreased the polarity of the films and considerably enhanced their water barrier properties. Thus, the water contact angle of films treated for 3 and 6 h was 97° and 102°, their water drop test value was higher than in untreated film (viz., 138 and 141 min with 3 and 6 h of treatment) and their water vapour transmission rate was substantially better (3.31 and 0.78 g m-2 day-1 with 3 and 6 h, respectively). The presence of aldehyde groups facilitated immobilization of the enzyme laccase, which efficiently captures oxygen and prevents food decay as a result. Laccase-containing films oxidized 80 % of Methylene Blue colorant and retained their enzymatic activity after storage for 1 month and 12 reuse cycles, opening the door to the possible creation of a reusable packaging to replace the single-use packaging.

Periodate oxidation of plant polysaccharides provides polysaccharide-specific oligosaccharides.

Although polysaccharides are frequently used in foods, detailed characterization and/or identification of their structures using a single method remains a challenge. We investigated the suitability of periodate oxidation as an approach to depolymerize polysaccharides, allowing characterization and/or identification of the original polysaccharides based on ESI-MS analyses of the released oligosaccharides. Various periodate oxidation conditions were tested on (arabino)xylan, galactomannan, xyloglucan and homogalacturonan. Each polysaccharide required a different oxidation condition to release a substantial level of oligosaccharides. These oligosaccharides had highly complex structures due to the presence of e.g., dialdehyde sugars, hemialdals, and remnants of (oxidized) sugars, as verified by ESI-MS/MS. Despite these oligosaccharides were highly complex and lost some polysaccharide structural features, each periodate-oxidized sample comprised polysaccharide structure-dependent MS oxidized oligosaccharide profiles. Our findings are a good starting point to find a more generic chemical polysaccharide depolymerization approach based on periodate oxidation to identify polysaccharides by oligosaccharides fingerprinting using MS.

Functionalisation of the non-reducing end of chitin by selective periodate oxidation: A new approach to form complex block polysaccharides and water-soluble chitin-based block polymers.

Most polysaccharides used in polysaccharide-based block copolymers are attached to the second block through the reducing end, due to the few and highly polysaccharide specific non-reducing end (NRE) functionalisation methods available. Chitin oligomers, prepared by nitrous acid degradation of chitosan (AnM) can, however, be selectively oxidised by periodate since they only possess a single vicinal diol in the NRE residue. Here, we show that both aldehydes formed after oxidation are highly reactive towards bifunctional oxyamines and hydrazide linkers. Sub-stochiometric amounts of linkers resulted in conjugation of AnM oligomers through both chain termini to yield a discrete distribution of 'polymerised' oligomers. Such chitin-based block polymers were, in contrast to chitins of the same chain lengths, water-soluble. Oxidised AnM oligomers, functionalised at both termini can also enable the preparation of more complex block polysaccharides such as ABA- or ABC-type.

Cu-decorated cellulose through a three-component Betti reaction: An efficient catalytic system for the synthesis of 1,3,4-oxadiazoles via imine CH functionalization of N-acylhydrazones.

Materials functionalization through multicomponent reactions (MCRs) has recently attracted great attention due to the generation of outstanding features in materials. Herein, an efficient novel heterogeneous catalytic system was designed and synthesized via the MCRs functionalization of the most abundant biopolymer in nature, cellulose. In this regard, cellulose was oxidized using periodate as an oxidant agent, and then the resulted carbonyl functional groups participated in the three-component Betti reaction. The ICP-OES analysis was revealed that the functionalization of cellulose via this three-component reaction effectively improved the complexing ability of functionalized cellulose with Cu(II). The synthesized biocatalyst was characterized by FT-IR, 1H NMR, XRD, SEM, EDS, ICP, and TGA techniques. The efficiency of the designed biocatalyst was investigated in the CH functionalization reaction of N-acylhydrazones to synthesize 1,3,4-oxadiazoles. This biocatalyst's outstanding advantages are high yields, non-hazardous catalyst, mild reaction conditions, operational simplicity, and reusability.

Reversible O-Acetyl Migration within the Sialic Acid Side Chain and Its Influence on Protein Recognition.

O-Acetylation is a common naturally occurring modification of carbohydrates and is especially widespread in sialic acids, a family of nine-carbon acidic monosaccharides. O-Acetyl migration within the exocyclic glycerol-like side chain of mono-O-acetylated sialic acid reported previously was from the C7- to C9-hydroxyl group with or without an 8-O-acetyl intermediate, which resulted in an equilibrium that favors the formation of the 9-O-acetyl sialic acid. Herein, we provide direct experimental evidence demonstrating that O-acetyl migration is bidirectional, and the rate of equilibration is influenced predominantly by the pH of the sample. While the O-acetyl group on sialic acids and sialoglycans is stable under mildly acidic conditions (pH < 5, the rate of O-acetyl migration is extremely low), reversible O-acetyl migration is observed readily at neutral pH and becomes more significant when the pH increases to slightly basic. Sialoglycan microarray studies showed that esterase-inactivated porcine torovirus hemagglutinin-esterase bound strongly to sialoglycans containing a more stable 9-N-acetylated sialic acid analog, but these compounds were less resistant to periodate oxidation treatment compared to their 9-O-acetyl counterparts. Together with prior studies, the results support the possible influence of sialic acid O-acetylation and O-acetyl migration to host-microbe interactions and potential application of the more stable synthetic N-acetyl mimics.

Fabrication and characterization of antibacterial epsilon-poly-L-lysine anchored dicarboxyl cellulose beads.

Pathogens in the food and environment pose a great threat to human health. To solve this problem, we described a novel route to synthesize antibacterial epsilon-poly-L-lysine (EPL) anchored dicarboxyl cellulose beads. Cellulose beads were prepared via a sol-gel transition method and oxidized by sodium periodate and sodium chlorite to form carboxyl groups. EPL was anchored on the beads using carbodiimide mediated amidation. The structure and morphology of beads were characterized by FTIR, XPS, XRD, SEM, and TGA. After dissolution and regeneration, the crystalline form of cellulose is transformed from cellulose I to cellulose II. The thermal degradation temperature of the beads is 200∼300 °C.The samples displayed excellent antimicrobial activity against Staphylococcus aureus, Alicyclobacillus acidoterrestris and Escherichia coli within 12 h. The beads could be biodegraded in soil after 20 days. The biodegradable beads exhibited great potential in food and environmental applications.

Structure and hypoglycemic activity of a novel exopolysaccharide of Cordyceps militaris.

A novel neutral exopolysaccharide (EPS-III) was isolated from culture broth of Cordyceps militaris (C. militaris). The EPS-III was a homogeneous polysaccharide with Mw of 1.56 × 103 kDa. The yield of EPS-III from culture broth was 123.2 ± 3.1 mg/L and the sugar content was 93.32 ± 0.87%. The backbone of EPS-III was mainly consisted of →4)-α-D-Galp-(1→, while →3, 6)-α-D-Manp-(1→, →4)-α-D-Manp-(1→, →3)-ß-D-Galp-(1→ and →3)-α-D-Glcp-(1→ were distributed in the backbone or in the branch chains. The EPS-III had helix structure when dissolved in weak alkaline solution. It also had branched and intertwined form on the surface. The inhibition of α-glucosidase significantly increased as the increase of purity of exopolysaccharides. The EPS-III had effective inhibition on the α-glucosidase with dose-effect relationship. Besides, the results of hypoglycemic activity analysis in vivo indicated that EPS-III can alleviate weight loss, reduce plasma glucose concentration, improve glucose tolerance, protect immune organs and repair dyslipidemia to relieve diabetes in STZ-induced diabetic mice. The manuscript first studied the hypoglycemic activity of exopolysaccharide of by C. militaris, proving and promoting the application value of culture broth. The structure characterization of EPS-III laid experimental foundations on the exploration of structure-activity relationship.

Diverse conditions contribute to the cholesterol-lowering ability of different Lactobacillus plantarum strains.

It has been reported that Lactobacillus can remove cholesterol and thus might play an important role in lowering cholesterol in humans, but the underlying mechanism is still controversial. To confirm whether different strains have different cholesterol-lowering mechanisms, we explored the cholesterol-lowering abilities of different Lactobacillus plantarum strains, and the factors influencing their abilities. We found that all nine strains reduced the cholesterol concentration to some extent, but there were significant differences among them. In MRS broth, L. plantarum AR113 and AR171 showed the greatest cholesterol-lowering abilities of 27.89% and 19.90%, respectively, but AR501 and AR300 only showed reductions of 0.34% and 0.91%, respectively. Upon addition of 0.1% ox bile, the cholesterol-removal capability of most strains increased. L. plantarum AR511 showed the highest cholesterol removal rate, which increased from 5.8% to 37.14%, i.e., by a factor of approximately 6.4, but there was no significant change in the cholesterol removal rate of AR171. These results suggested that the effect of ox bile on the cholesterol-lowering ability was strain-specific. Except for the strains AR171, AR237 and AR495, the cholesterol-removal ability of the remaining six strains was positively correlated with the amount of free bile acid released. The addition of a bile salt hydrolase inhibitor had some effect on the cholesterol-removal ability of the six strains of bacteria other than AR171, AR237 and AR495, but little influence on the latter three. The effect of BSH was strain-specific. Similarly, the effect of pH was also strain-specific. Taken together, these results suggest that different strains of L. plantarum have different cholesterol-lowering capacities and different influencing factors. Therefore, further research is needed to explore the exact mechanism by which different strains lower cholesterol.

Deep Learning-Based Segmentation and Quantification in Experimental Kidney Histopathology.

BACKGROUND: Nephropathologic analyses provide important outcomes-related data in experiments with the animal models that are essential for understanding kidney disease pathophysiology. Precision medicine increases the demand for quantitative, unbiased, reproducible, and efficient histopathologic analyses, which will require novel high-throughput tools. A deep learning technique, the convolutional neural network, is increasingly applied in pathology because of its high performance in tasks like histology segmentation. METHODS: We investigated use of a convolutional neural network architecture for accurate segmentation of periodic acid-Schiff-stained kidney tissue from healthy mice and five murine disease models and from other species used in preclinical research. We trained the convolutional neural network to segment six major renal structures: glomerular tuft, glomerulus including Bowman's capsule, tubules, arteries, arterial lumina, and veins. To achieve high accuracy, we performed a large number of expert-based annotations, 72,722 in total. RESULTS: Multiclass segmentation performance was very high in all disease models. The convolutional neural network allowed high-throughput and large-scale, quantitative and comparative analyses of various models. In disease models, computational feature extraction revealed interstitial expansion, tubular dilation and atrophy, and glomerular size variability. Validation showed a high correlation of findings with current standard morphometric analysis. The convolutional neural network also showed high performance in other species used in research-including rats, pigs, bears, and marmosets-as well as in humans, providing a translational bridge between preclinical and clinical studies. CONCLUSIONS: We developed a deep learning algorithm for accurate multiclass segmentation of digital whole-slide images of periodic acid-Schiff-stained kidneys from various species and renal disease models. This enables reproducible quantitative histopathologic analyses in preclinical models that also might be applicable to clinical studies.

Optimizing the properties of Zodo gum and examining its potential for amino acid binding by periodate oxidation.

In this study, the Zodo gum exudated by Amygdalus scoparia spach underwent the periodate oxidation process for chemical modification and the formation of dialdehyde groups. Modification of the Zodo gum properties was done using the periodate oxidation method, response surface methodology (RSM) and central composite design (CCD), with 4 factors of sodium periodate volume (6.4-19.2 mL), temperature (35-55 °C), pH (3-5) and time (2-4 h). Dialdehyde Zodo gum (DZG) was produced by controlling test variables and measuring some responses including dialdehyde content and efficacy, in addition to evaluating the rheological parameters. Quadratic, linear polynomial equations were then fitted with the insignificant Lack of fit and high R2 to address the relationship between the mentioned variables and responses. Optimal test conditions, including pH = 3.9, T = 43 °C and Time = 3.5 h, were also determined for the production of DZG10, DZG20 and DZG30 samples. The results of 1H-13C NMR, FTIR and determination of the aldehyde content indicated the formation of dialdehyde groups in equilibrium with the dominant hemiacetal form. The AFM study of the DZG30 sample also showed over-oxidation and depolymerization, which could be associated with increased hydrophobic properties and the reduced viscosity. Although the DZG30 sample had the highest amount of the dialdehyde factor group with the tendency to combine with the amino group of proteins, DZG10 and DZG20 samples could be recommended for industrial applications due to the nonoccurrence of overoxidation.

Bioorthogonal chemistry-based RNA labeling technologies: evolution and current state.

To understand the structure and ensuing function of RNA in various cellular processes, researchers greatly rely on traditional as well as contemporary labeling technologies to devise efficient biochemical and biophysical platforms. In this context, bioorthogonal chemistry based on chemoselective reactions that work under biologically benign conditions has emerged as a state-of-the-art labeling technology for functionalizing biopolymers. Implementation of this technology on sugar, protein, lipid and DNA is fairly well established. However, its use in labeling RNA has posed challenges due to the fragile nature of RNA. In this feature article, we provide an account of bioorthogonal chemistry-based RNA labeling techniques developed in our lab along with a detailed discussion on other technologies put forward recently. In particular, we focus on the development and applications of covalent methods to label RNA by transcription and posttranscription chemo-enzymatic approaches. It is expected that existing as well as new bioorthogonal functionalization methods will immensely advance our understanding of RNA and support the development of RNA-based diagnostic and therapeutic tools.

Synthesis and Characterization of Oxidized Polysaccharides for In Situ Forming Hydrogels.

Polysaccharides are widely used as building blocks of scaffolds and hydrogels in tissue engineering, which may require their chemical modification to permit crosslinking. The goal of this study was to generate a library of oxidized alginate (oALG) and oxidized hyaluronic acid (oHA) that can be used for in situ gelling hydrogels by covalent reaction between aldehyde groups of the oxidized polysaccharides (oPS) and amino groups of carboxymethyl chitosan (CMC) through imine bond formation. Here, we studied the effect of sodium periodate concentration and reaction time on aldehyde content, molecular weight of derivatives and cytotoxicity of oPS towards 3T3-L1 fibroblasts. It was found that the molecular weights of all oPs decreased with oxidation and that the degree of oxidation was generally higher in oHA than in oALG. Studies showed that only oPs with an oxidation degree above 25% were cytotoxic. Initial studies were also done on the crosslinking of oPs with CMC showing with rheometry that rather soft gels were formed from higher oxidized oPs possessing a moderate cytotoxicity. The results of this study indicate the potential of oALG and oHA for use as in situ gelling hydrogels or inks in bioprinting for application in tissue engineering and controlled release.

Design of tunable gelatin-dopamine based bioadhesives.

Bioadhesives have a potential to modulate the wound closure process with significant biological outcomes. However, none of the currently commercialized adhesives are satisfactory in their performance. It is a challenging task to develop an adhesive system that can work on wet surface and enhances tissue repair and closure. In this study, we have fabricated a series of gelatin-dopamine (Gel-dop) conjugates and studied their adhesive properties after being chemically crosslinked using sodium periodate. The designed material was assessed for its adhesive properties including tensile, lap shear and peeling study by varying the degree of dopamine substitution. It was observed that the adhesive property has a direct correlation with increase in dopamine content until reaching a maximum and then a subsequent decrease. We tested the adhesive strength of the different formulations by varying the degree of substitution and compared against fibrin glue, which is considered as the gold standard of adhesives. The formulation with a moderate substitution degree demonstrated the optimal adhesive property than those formulations with lower and larger substitution degree. Further, the in vitro cytotoxicity study showed that this tunable Gel-dop adhesives are to non-cytotoxic, indicating a potential use in clinic applications. This study illustrates that adhesiveness can be regulated by changing the degree of dopamine substitution.

Bio-Based Thermoplastic Starch Composites Reinforced by Dialdehyde Lignocellulose.

In order to improve the mechanical properties and water resistance of thermoplastic starch (TPS), a novel reinforcement of dialdehyde lignocellulose (DLC) was prepared via the oxidation of lignocellulose (LC) using sodium periodate. Then, the DLC-reinforced TPS composites were prepared by an extrusion and injection process using glycerol as a plasticizer. The DLC and LC were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the effects of DLC content on the properties of the DLC/TPS composites were investigated via the evaluation of SEM images, mechanical properties, thermal stability, and contact angles. XRD showed that the crystallinity of the DLC decreased due to oxidation damage to the LC. SEM showed good dispersion of the DLC in the continuous TPS phase at low amounts of DLC, which related to good mechanical properties. The tensile strength of the DLC/TPS composite reached a maximum at a DLC content of 3 wt.%, while the elongation at break of the DLC/TPS composites increased with increasing DLC content. The DLC/TPS composites had better thermal stability than the neat TPS. As the DLC content increased, the water resistance first increased, then decreased. The highest tensile strength and elongation at break reached 5.26 MPa and 111.25%, respectively, and the highest contact angle was about 90.7°.

Controlling the transparency and rheology of nanocellulose gels with the extent of carboxylation.

TEMPO and periodate are combined in a one-shot reaction to oxidise cellulose and produce nanocellulose gels with a wide range of degree of substitution (DS). Highly-oxidised cellulose nanofibres with a high charge of -80 mV were produced. The strong electrical repulsion between TEMPO-periodate oxidised nanofibres (TPOF) results in the formation of well-separated nanofibres with a diameter of 2-4 nm, albeit depolymerised due to high oxidation. TPOF produces highly-transparent gels due to smaller aspect ratio and high surface charge. These properties induce a reduced viscosity and moduli of the gels by decreasing fibre entanglement. TPOF gels are more stable at basic pH and high ionic strength than TEMPO-oxidised gels due to their higher surface charge. Freeze-dried TPOF gels also exhibit remarkable water holding capacity due to enhanced immobilisation of water molecules. The excellent optical properties of the highly transparent gel for red blood cells analysis open new possibilities in diagnostics application.

hFRUIT: An optimized agent for optical clearing of DiI-stained adult human brain tissue.

Here, we describe a new immersion-based clearing method suitable for optical clearing of thick adult human brain samples while preserving its lipids and lipophilic labels such as 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI). This clearing procedure is simple, easy to implement, and allowed for clearing of 5 mm thick human brain tissue samples within 12 days. Furthermore, we show for the first time the advantageous effect of the Periodate-Lysine-Paraformaldehyde (PLP) fixation as compared to the more commonly used 4% paraformaldehyde (PFA) on clearing performance.

Rapid sodium periodate cleavage of an unnatural amino acid enables unmasking of a highly reactive α-oxo aldehyde for protein bioconjugation.

The α-oxo aldehyde is a highly reactive aldehyde for which many protein bioconjugation strategies exist. Here, we explore the genetic incorporation of a threonine-lysine dipeptide into proteins, harbouring a "masked"α-oxo aldehyde that is rapidly unveiled in four minutes. The reactive aldehyde could undergo site-specific protein modification by SPANC ligation.

Monitoring cellulose oxidation for protein immobilization in paper-based low-cost biosensors.

The oxidation of paper by periodate was investigated and systematically characterized by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, X-ray diffraction, goniometry, and dynamic mechanical analysis. For the first time, in situ FTIR microscopy analysis was performed, yielding chemical images of carbonyl groups on the cellulose fibers. The enhancement of protein immobilization on oxidized paper was quantified by a colorimetric assay with Ponceau dye, demonstrating that 0.5-h oxidation suffices to functionalize the paper-based devices. The oxidized paper was applied as a sensor for protein quantification in urine, a test able to detect levels of proteinuria and even microalbuminuria. The quantification was based on the capture of proteins through covalent bonds formed with the carbonyl groups on the oxidized paper followed by the staining of the region with Ponceau dye. There is a linear dependency between human serum albumin (HSA) concentration and the length of the stained blot from 0.1 to 3 mg mL-1. This method correlated linearly with a reference method showing a higher sensitivity (0.866 cm mL mg-1) than the latter. The limit of quantification was 0.1 mg mL-1, three times lower than that of the commercial strip. Graphical abstract Paper oxidation with periodate and extensive characterization, including microspectroscopy. The conversion of cellulose hydroxyl groups to aldehyde enhances covalent immobilization of protein on paper for application as analytical device. The oxidized paper determined protein in urine, suitable for proteinuria diagnosis.

Nano-crystalline cellulose-coated magnetic nanoparticles for affinity adsorption of glycoproteins.

A new core-shell structured nanomaterial based on Fe3O4 nanoparticles and 2,3-dialdehyde nanocrystalline cellulose (DAC) coating and its high efficiency in the preconcentration of glycoproteins were described in this work. DAC was obtained after the periodate oxidation of nanocrystalline cellulose to form aldehyde groups; then, Fe3O4 nanoparticles were coated with DAC, which were further attached to 4-aminophenylboronic acid (PBA) to form PBA-functionalized magnetic core-shell structured materials (Fe3O4@DAC-PBA). The oxidation of cellulose and the production of sufficient amounts of aldehyde group sites were essential for the preparation of Fe3O4@DAC-PBA used for the affinity adsorption of glycoproteins because the aldehyde groups on DAC allowed DAC to attach to the Fe3O4 nanoparticles and bind with PBA, which was active in forming a complex with the glyco sites in glycoproteins. Moreover, the preconcentration properties of Fe3O4@DAC-PBA through PBA adsorption can be pH-triggered without the disassembly of the structures; thus, the developed Fe3O4@DAC-PBA can be efficiently prepared to provide a promising affinity material for the affinity adsorption and purification of glycoproteins.