Study of the cell responses in tantalum carbide nanoparticles-enriched polysaccharide composite hydrogel

Preparation, characterization and drug release properties of pH sensitive Zingiber officinale polysaccharide hydrogel beads

The aim of this study was to prepare a drug carrier that could deliver oral insulin to the intestine. A hydrogel beads composed of sodium carboxymethyl cellulose (CMC), Zingiber offtcinale polysaccharide (ZOP) and chitosan (CS) were prepared by ionic gel method as insulin carrier. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and thermogravimetric (TGA) showed that the hydrogel was formed by metal ion coordination between ZOP and CMC and Fe3+, and CS was coated on the surface of the hydrogel ball in the form of non covalent bond. The results showed that the swelling process of hydrogel spheres has significant pH sensitivity. In addition, the hydrogel beads successfully coated insulin, and the drug loading rate (DL) of (ZOP/CMC-Fe3+)@CS could reach 69.43 ± 7.32 mg/g, and the entrapment efficiency (EE) could reach 66.94 ± 7.43 %. In vitro release experiments, the release rate of (CMC/ZOP-Fe3+)@CS in simulated gastric fluid (SGF) for 2 h was <20 %, and the cumulative release rate of insulin after 9 h in simulated intestinal fluid (SIF) reached over 90 %. The results showed that the hydrogel beads prepared in this work could be used as a potential carrier for delivering oral insulin.

Photo-degradable salecan/xanthan gum ionic gel induced by iron (III) coordination for organic dye decontamination

As dye adsorbents with great potential, polysaccharide-based hydrogels are significantly hampered in practical application owing to intricate preparation methods, low absorption, and bad degradability. Salecan is a water-soluble extracellular polysaccharide with excellent physicochemical and biological properties. Here, salecan and xanthan gum were first used as a dual-precursors system, their mixed solution was crosslinked by Fe³⁺ to assemble a photo-degradable ionic gel for malachite green (MG) adsorption. Photo-degradation was done using visible light under very mild conditions, which gave rise to gel network dissolution and homogeneous solution formation. Extensive dynamic coordinate interactions between Fe³⁺ and polysaccharides maintained gel matrix stability and were systematically investigated. The control of water uptake, micro-structure, and rheology can be facilely implemented by tuning salecan/xanthan gum ratios. Furthermore, various parameters such as polysaccharide ratios, pHs, MG concentrations, and contact time affecting adsorption were optimized using batch experiments. Adsorption process accurately adhered to pseudo-second-order kinetic and Langmuir isotherm model, with the maximum adsorption capacity of 463.0 mg/g. Such mechanism implied monolayer chemisorptive characteristics. The gel exhibited satisfactory reusability and was recycled five times without apparent decrease in adsorption capacity. From these results, the photo-degradable Fe³⁺-induced salecan/xanthan gum ionic gel is an alternative and sustainable absorbent for MG removal.

The Synthesis, Characterization, and Protein-Release Properties of Hydrogels Composed of Chitosan-Zingiber offcinale Polysaccharide

Most proteins given orally have low bioavailability and are easily eliminated by rapid metabolism in vivo. In order to immobilize the drug at the site of administration and delay its release, a natural, gentle release system was designed. In this study, a heteropolysaccharide (ZOP) was isolated from Zingiber officinale using an ultrasonic assisted extraction method. ZOP Ara = 1.97: 1.15: 94.33: 1.48: 1.07. The ZOP/Chitosan (CS) composite hydrogel was synthesized using epichlorohydrin (ECH) as a cross-linking agent. The structure, morphology, and water-holding capacity of the composite hydrogel were characterized. The data showed that the addition of ZOP improved the hardness and water-holding capacity of the material. A swelling ratio test showed that the prepared hydrogel was sensitive to pH and ionic strength. In addition, the degradation rate of the hydrogel in a phosphate-buffered saline (PBS) solution with a pH value of 1.2 was higher than that in PBS with pH value of 7.4. Similarly, the release kinetics of Bovine serum albumin (BSA) showed higher release in an acidic system by the hydrogel composed of ZOP/CS. The hydrogel prepared by this study provided a good microenvironment for protein delivery. In summary, this composite polysaccharide hydrogel is a promising protein-drug-delivery material.

Construction of Hohenbuehelia serotina polysaccharides-mucin nanoparticles and their sustain-release characteristics under simulated gastrointestinal digestion in vitro

In this study, Hohenbuehelia serotina polysaccharides-mucin nanoparticles (HSP-MC NPs) were fabricated based on hydrogen bonding and hydrophobicity effects for improving the bioavailability of HSP. The structural characteristics and morphology of HSP-MC NPs prepared by different conditions were respectively identified and observed. The results showed that HSP-MC NPs (HSP/MC, 1/1, w/w) presented the optimal physicochemical characteristics, with the encapsulation efficiency of 88.09 ± 0.01%, average particle size of 509.4 ± 9.76 nm and zeta potential of -20.6 ± 0.7 mV. Furthermore, HSP-MC NPs (HSP/MC, 1/1, w/w), belonged to non-crystalline substances, exhibited the excellent physicochemical stabilities against temperature, pH and ionic strength, and had the uniform spherical morphological characteristics. In addition, under simulated gastrointestinal digestion in vitro, HSP-MC NPs (HSP/MC, 1/1, w/w) showed the good sustained release performances, that might effectively improve the absorption rate of HSP. The present research is meaningful for designing the polysaccharides-loaded nano-delivery system based on natural non-toxic carrier that can be used in function food field.

Simple ultrasonic-assisted approach to prepare polysaccharide-based aerogel for cell research and histocompatibility study

Salecan, a water-soluble microbial polysaccharide with attractive biocompatible characteristics, is very suitable for aerogel fabrication. However, the practical application of salecan-based aerogels for cell culture was limited by complicated preparation method, lack of cell anchorage signals, and the ability to modulate this properly. Here, a smart aerogel was designed by ultrasonic-assisted self-assembly of salecan and cationic starch (CAS) without any organic and toxic crosslinkers. The ultrasound waves generated a marked impact on self-assemble process by means of ultrasonic cavitation. Aerogel network was produced by strong electrostatic attractions between the polysaccharides. Especially, salecan/CAS ratio can be precisely modulated to tailor the hydrophilicity, mechanical stiffness, and morphologic property. The specific surface area of the aerogels gradually increased with the increase in salecan/CAS ratio. These aerogels were non-cytotoxic, and the incorporation of salecan into them promoted cell-matrix interactions by directionally supporting cell adhesion and proliferation. Most strikingly, in vivo experiment revealed that the histological features in the main organs of the mice were similar to those observed in the PBS-treated control group, and no sign of the histopathological abnormality or tissue destruction was observed, indicating the excellent histocompatibility of the aerogels. This study offered a new and powerful avenue to fabricate functional biomaterial.

Tantalum(v) peroxido complexes as phosphatase inhibitors: a comparative study vis-a-vis peroxidovanadates

Peroxido Ta(v) complexes are found to be more effective as inhibitors of wheat thylakoid acid phosphatase vis-à-vis their V containing analogues. In addition, these compounds showed unique resistance towards degradation in the presence of catalase.

Quantification of schizophyllan directly from the fermented broth by ATR-FTIR and PLS regression

Non-destructive methods that allow the quantification of bioproducts in a simple and quick manner during fermentation are extremely desirable from a practical point of view. Therefore, a 9 day fermentation experiment with Schizophyllum commune was carried out to investigate the possibility of using ATR-FTIR to quantify the schizophyllan biopolymer (SPG) directly from the culture medium. On each day, aliquots of the fermentation were taken, and the cell-free supernatant was analyzed by ATR-FTIR. The main objective of this step was to evaluate whether FTIR would be able to detect the appearance of specific peaks related to the production of SPG. The results of the PCA analysis showed that there was a reasonable separation of the days through the FTIR spectra. Then PCA-LDA was applied to the same dataset, which confirmed the formation of groups for each day of fermentation, after which, a calibration and test set was developed. Through a matrix generated by an experimental design with 2 factors and 5 levels, 25 samples were created with variations in the concentration of the culture medium and SPG. The ATR-FTIR spectra of this data set were modeled using PLS regression with backward selection of predictors. The results revealed that the amount of SPG produced can be quantified directly in the culture medium with excellent precision with R²CV = 0.951, R²P = 0.970, RMECV = 0.205 g, RMSEP = 0.170 g, RPDcv = 4.53 and RPDp = 5.88. The traditional method to quantify SPG is time consuming, requires several steps and uses solvents. In contrast, the method proposed in this work is a viable, faster, and a simpler alternative, which does not use reagents and does not require extensive pre-treatment of the samples.

Magnetic nanoparticles double wrapped into cross-linked salep/PEGylated carboxymethyl cellulose; a biocompatible nanocarrier for pH-triggered release of doxorubicin

A magnetic nanocarrier was synthesized in which Fe3O4 nanoparticles were encapsulated into double layers of polysaccharide shells. The first shell, which was composed of cross-linked salep polysaccharide, contained multiple nitrogen atoms in its structure and provided numerous sites for multiple functionalization. A fluorescence dye and doxorubicin, as widely used chemotherapy agent, were easily attached to the first shell and then a second shell of PEGylated carboxymethyl cellulose enveloped the drug loaded carrier to enhance its biocompatibility and regulates the drug release behavior. The results of drug loading and release behavior showed that the resulting nanocarrier can carry large amounts of drug molecules and a remarkable pH-sensitive release was observed in vitro. The hemolysis and coagulation assays proved the biocompatibility of nanocarrier toward red blood cells and the MTT experiments confirmed that the drug loaded nanocarrier is highly toxic for MCF-7 cancer cells while the unloaded nanocarrier was almost nontoxic. Further flow cytometry experiments and confocal microscopy demonstrated that the double layered magnetic nanocarrier can penetrate into the cells and efficiently release the drug molecules into the cell nucleus. Moreover, the results of MRI experiments performed on the nanocarrier showed that it can be serve as a negative MRI contrast agent.

The Role of Tantalum Nanoparticles in Bone Regeneration Involves the BMP2/Smad4/Runx2 Signaling Pathway

Background

In recent years, nanomaterials have been increasingly developed and applied in the field of bone tissue engineering. However, there are few studies on the induction of bone regeneration by tantalum nanoparticles (Ta NPs) and no reports on the effects of Ta NPs on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the underlying mechanisms. The main purpose of this study was to investigate the effects of Ta NPs on bone regeneration and BMSC osteogenic differentiation and the underlying mechanisms.

Materials and Methods

The effects of Ta NPs on bone regeneration were evaluated in an animal experiment, and the effects of Ta NPs on osteogenic differentiation of BMSCs and the underlying mechanisms were evaluated in cell experiments. In the animal experiment, hematoxylin-eosin (HE) staining and hard-tissue section analysis showed that Ta NPs promoted bone regeneration, and immunohistochemistry revealed elevated expression of BMP2 and Smad4 in cells cultured with Ta NPs.

Results

The results of the cell experiments showed that Ta NPs promoted BMSC proliferation, alkaline phosphatase (ALP) activity, BMP2 secretion and extracellular matrix (ECM) mineralization, and the expression of related osteogenic genes and proteins (especially BMP2, Smad4 and Runx2) was upregulated under culture with Ta NPs. Smad4 expression, ALP activity, ECM mineralization, and osteogenesis-related gene and protein expression decreased after inhibiting Smad4.

Conclusion

These data suggest that Ta NPs have an osteogenic effect and induce bone regeneration by activating the BMP2/Smad4/Runx2 signaling pathway, which in turn causes BMSCs to undergo osteogenic differentiation. This study provides insight into the molecular mechanisms underlying the effects of Ta NPs in bone regeneration.

Transition Metal Carbide Core/Shell Nanoparticles by Ultra-Short Laser Ablation in Liquid

Transition metal carbide nanoparticles are a class of technological interesting materials with a wide range of applications. Among metal carbides, tantalum carbides have good compatibility with the biological environment while molybdenum carbides are used as catalyst in electrochemical reactions. Laser ablation of bulk transition metal targets in some liquids is here reported and laser ablation in organic solvents is used as simple synthetic strategy for the production of carbide nanostructures. Herein, the nanoparticles produced by ultra-short laser ablation of tantalum and molybdenum in water, acetone, ethanol and toluene have been characterized by TEM, XRD and XPS analysis. The combined effect of metal and solvent chemical and physical properties on the composition of the nanomaterials obtained has been pointed out. In particular, the different reactivity of Ta and Mo with respect to oxidizing species determines the composition of particles obtained in water, on the other hand the organic solvents decomposition allows to obtain transition metal carbide (TMC) nanoparticles. The observed carbonaceous shell formed on TMC allows to protect the particle's carbidic core and to improve and tailor the applications of these nanomaterials.

Tough, stretchable and compressive alginate-based hydrogels achieved by non-covalent interactions

In this study, two alginate-based hydrogels with good mechanical strength, toughness and resilience were synthesized by hydrophobic interaction and coordination bonding. Sodium alginate/poly(acrylamide) semi-interpenetrating network (NaAlg/PAM semi-IPN) hydrogels were first synthesized through the micelle copolymerization of acrylamide and stearyl methacrylate in the presence of sodium alginate, then calcium alginate/poly(acrylamide) double network (CaAlg/PAM DN) hydrogels were prepared by immersing the as-prepared NaAlg/PAM semi-IPN hydrogels in a CaCl₂ solution. FT-IR and XPS results revealed NaAlg/PAM semi-IPN hydrogels and CaAlg/PAM DN hydrogels were successfully synthesized through non-covalent interactions. The tensile strength of CaAlg/PAM DN hydrogels could reach 733.6 kPa, and their compressive strengths at 80% strain are significantly higher than those of the corresponding NaAlg/PAM semi-IPN hydrogels, which is attributed to the alginate network crosslinked by Ca²⁺. The dual physically crosslinked CaAlg/PAM DN hydrogels can achieve fast self-recovery, and good fatigue resistance, which is mainly assigned to energy dissipation through dynamic reversible non-covalent interactions in both networks. The self-healing ability, swelling behavior and morphology of the synthesized alginate-based hydrogels were also evaluated. This study offers a new avenue to design and construct hydrogels with high mechanical strength, high toughness and fast self-recovery properties, which broadens the current research and application of hydrogels.

Alginate-based hydrogels based on non-covalent interactions were synthesized, and exhibited good mechanical strength, toughness and resilience.