Superhydrophilic hydrogel was typically used as the membrane coating on various substrates for oil/water separation. Nevertheless, these coatings may suffer from such limitations as poor adhesion strength and abrasion-resistance. Thus, the facile construction of hydrogel sponge with 3D connecting channels would be an ideal choice.
View Article and Find Full Text PDFThe spontaneous self-organization of naturally-occurring polysaccharide particles into a thick and robust gel network at interface in Pickering emulsion is challenging. Inspired by the phenomenon that chitosan microgels (CSMs) with a certain size could self-associate into a solidified gel phase upon freezing, here we tentatively used CSMs to construct a highly-stable Pickering emulsion. CSMs can form a stable Langmuir's layer at the water/oil interface through the network deformation and re-arrangement of dangling chains, while the subsequent negative polymer coating can avoid the bridging resulting from the cross-association for CSMs on different emulsion droplets upon freezing.
View Article and Find Full Text PDFWith a large theoretical capacity and high energy density, aluminum-air batteries are a promising energy storage device. However, the rigid structure and liquid electrolyte of a traditional aluminum-air battery limit its application potential in the field of flexible electronics, and the irreversible corrosion of its anode greatly reduces the battery life. To solve the above problems, a PVA/KC/KOH (2 M) composite gel polymer electrolyte (GPE) with a three-dimensional dual-network structure consisting of polyvinyl alcohol (PVA), kappa-carrageenan (KC), and potassium hydroxide was prepared in this paper by a simple two-step method and applied in aluminum-air batteries.
View Article and Find Full Text PDFWhile oral administration offers safety benefits, its therapeutic efficacy is hindered by various physiological factors within the body. In this study, a novel approach was explored using a matrix consisting of 2 % chitosan and 2 % gelatin, with citric acid (CA) serving as a green cross-linking agent (ranging from 0.4 % to 1.
View Article and Find Full Text PDFBio-based food packaging materials have elicited growing interests due to their great degradability, high safety and active biofunctions. In this work, by simultaneously introducing the polyphenolic extracts from Capsicum annuum leaves and ferric ion (Fe) into the Polyvinyl alcohol/kappa-carrageenan (PVA/κ-carrageenan)-based film-forming matrix, an active package film was developed, with the purpose to improve the food shelf life. The experimental results indicated that the existence of Fe can not only improve the mechanical properties owing to the multiple dynamic coordinated interactions, but also endow the composite films with excellent fire-retardancy.
View Article and Find Full Text PDFThe traditional κ-carrageenan (κCG)-based hydrogel obtained from hot water can rupture easily under mechanical loading. To address this vulnerability, here we presented a robust all-κCG hydrogel without employing the second synthetic network. By simply regulating the polymer chains from random coil to stiff chain conformation in NaOH/urea solvent system via the freeze-thawing process, the as-prepared hydrogel with homogeneous structure can display an enhanced stretchability from 42.
View Article and Find Full Text PDFBackground: Constipation seriously affects people's life quality, and dietary adjustment has been one of the effective methods. Overall dietary quality has been reported to be associated with some diseases, while its association with constipation has not been reported. This study aims to explore the association between overall dietary quality and constipation.
View Article and Find Full Text PDFRaspberry anthocyanin (RA) from Rubus idaeus L. (Rosaceae) and curcumin (Cur) from Curcuma longa L. (Zingiberaceae) can effectively improve the physicochemical properties of composite films, and as bioactive pigment components, they can impart pH-responsive properties to the film.
View Article and Find Full Text PDFThe development of adsorbents by using the byproducts or waste from large-scale industrial and agricultural production is of great significance, and is considered to be an economic and efficient strategy to remove the heavy metals from polluted water. In this work, a novel chitin/EM@FeO nanocomposite hydrogel was obtained from a NaOH/urea aqueous system, where the proteins of egg shell membrane and FeO nanoparticles were chemically bonded to chitin polymer chains with the help of epichlorohydrin. Due to the existence of a large number of -NH, -OH, -CONH-, -COOH and hemiacetal groups, the adsorption efficiency for Pb into the absorbent was dramatically enhanced.
View Article and Find Full Text PDFA novel strategy to fabricate bilayer hydrogel actuators based on the asymmetric distribution of crystalline regions across the bilayer structures was proposed. By employing PVA polymer chains into an alkali solvent-derived chitosan hydrogel matrix, chitosan/PVA hybrid bilayer hydrogels with both excellent responsive bending and mechanical properties were obtained as pH-controlled manipulators. In the design, the chitosan/PVA hydrogels upon treatment with freeze-thawing cycles were taken as the first monolayer, where excessive crystalline regions appeared.
View Article and Find Full Text PDFThe unique conformation transition from a triple helix to single coils for the triple helical β-d-glucans has paved the way to fabricate various functional nanocomposites through the denaturing-renaturing process. This study firstly reports a novel kind of naturally derived supramolecular polymer micelle consisting of single-stranded chains of curdlan (CUR) and β-CDs. It is proposed that β-CDs as the host molecules were threaded onto single β-glucan chains (denatured triplex CUR) via the host-guest interaction, thereby forming supramolecular micelles.
View Article and Find Full Text PDFChitosan hydrogel microspheres derived from the LiOH/KOH/urea aqueous system demonstrate great characteristics of high mechanical strength, relative chemical inertness, renewability and 3-D fibrous network, making them promising functional supports. This work aims to investigate the tunable Co adsorption behaviors on these robust chitosan microspheres in detail, providing the theoretical basis for optimizing the preparation procedure of chitosan microspheres supported CoO catalysts in the future. The experimental results revealed that the fabricated original chitosan microspheres with more extended chain conformation could display enhanced adsorption capacity for Co at determined concentration both in water and alcohol solutions, which is about 2-7 times higher than that of the conventional chitosan hydrogel microspheres prepared from the acetic acid solution.
View Article and Find Full Text PDFSelf-floating hollow glass microspheres (HGMS) modified with tumor-specific antibodies have been developed for the capture of circulating tumor cells (CTCs), and have demonstrated effective cell isolation and good viability of isolated cancer cells. However, the capture efficiency decreases dramatically if the spiked cell concentration is low, possibly due to insufficient interactions between cancer cells and the HGMS surface. In order to apply HGMS-based CTC isolation to clinically relevant samples, it is desirable to create nanostructures on the surface of HGMS to enhance cell-surface interactions.
View Article and Find Full Text PDFCovalent organic frameworks (COFs), featuring low densities, high surface areas, and good thermal and chemical stabilities, are gradually attracting interest in the field of analytical chemistry. A type of microporous polymer network material named Schiff base network-1 (SNW-1) was introduced into a capillary column through covalent bonding. The obtained SNW-1-coated capillary column was characterized by thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction.
View Article and Find Full Text PDFIn this study, a metal-organic framework (MOF), [Mn(cam)(bpy)], was synthesized and characterized by thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectrometry. An open-tubular capillary column was fabricated from [Mn(cam)(bpy)] via the amide coupling method. Ten types of sulfonamides were separated through the fabricated capillary column, which showed a good limits of detection (<0.
View Article and Find Full Text PDFThe authors report that graphene oxide nanoribbons exert a strong catalytic effect on the reduction of HAuCl by HO to form gold nanoparticles which display nanoplasmonic surface enhanced Raman scattering (SERS) activity, Rayleigh scattering and absorption. If an aptamer against Pb(II) is present in solution, it will bind to the graphene oxide nanoribbons and thereby inhibit their catalytic activity. Upon addition of Pb(II), it will bind to the aptamer to form stable complexes and release free graphene oxide nanoribbon.
View Article and Find Full Text PDFMercury (Hg) is a heavy metal pollutant, there is an urgent need to develop simple and sensitive methods for Hg(II) in water. In this article, a simple and sensitive resonance Rayleigh scattering (RRS) method was developed for determination of 0.008-1.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
November 2016
Arsenic is a toxic metal element and the establishment of a highly sensitive and selective method for As has great significance to human health and environment protection. In sulfuric acid medium, As(Ⅲ) was reduced by NaBH4 to form AsH3 gas that was trapped by the Ce(Ⅳ)-I- catalytic absorption solution to cause Ce(Ⅳ) concentration decreased and As particle increased, which resulted in the resonance Rayleigh scattering (RRS) and fluorescence increased at 370 and 351 nm respectively. The increased RRS and fluorescence intensities were linear to As(Ⅲ) concentration in the range of 0.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
September 2016
In acidic solutions, Bi(III) was reduced by NaBH4 to form BiH3 gas. Using I3(-)graphene oxide (GO) as absorption solution, the BiH3 gas reacted with I3(-) to form I(-) that resulted in the I3(-) concentration decreasing. In the absence of BiH3, the I3(-) concentration was high, and as receptors it was closed to the surfaces of GO which was as donors.
View Article and Find Full Text PDFIn pH 7.4 Na2HPO4-NaH2PO4 buffer solution containing the peptide probes for human chorionic gonadotropin (hCG), silver nanoparticles (AgNPs) were aggregated to big AgNPs clusters that exhibited very weak catalytic effect on the gold nanoparticle reaction of H2O2-HAuCl4. When hCG was present in the peptide probe solution, the AgNPs did not aggregate and it had strong catalytic effect on the gold nanoparticle reaction with a strong resonance Rayleigh scattering (RRS) peak at 370nm and a strong surface enhanced Raman scattering (SERS) peak at 1615cm(-1) in the presence of molecular probe of Victoria blue 4R (VB4R).
View Article and Find Full Text PDFYeast β-glucan has many formulations with different chemical structures, water solubility and purity. In particular, the purity of β-glucan in these formulations is variable and relatively low, contributing to different data on its biological activity. In this study, the major polysaccharide component in the crude Baker's yeast polysaccharides coded as BBG with high purity of 99% was obtained, and its chemical structure was determined to be a linear β-(1,3)-glucan.
View Article and Find Full Text PDF