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Native starches and their phosphates with various molecular structures was introduced as the depressant to realize the flotation of quartz from hematite in this study. The present starch phosphates (WSP, NSP, GSP) were modified by the reaction between phosphate and three different corn starches (WS, NS, G50). The synthesis and characterization of starch phosphates found that starch with high amylopectin content was easily modified into starch phosphates. Microflotation tests showed that starch phosphates exhibited stronger depressing abilities of hematite flotation than native starches. Zeta potential measurement showed that both starches and starch phosphates could positively shift the zeta potential of hematite, while starch phosphates had more effects than starches. XPS and MDS indicated that the chemisorption occurred between Fe of hematite surface and C O groups of starch-based depressants. In addition, starch phosphates could adsorb onto the hematite surface through P O groups. MDS also presented that the adsorption strength of starch phosphate was mainly determined by the type and number of generating chelating rings, and the molecular structure of starch significantly affected the formation of chelate rings. The proposed adsorption model insights will significantly promote the development of starch-based depressants for iron ore flotation and other mineral processing applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of the current study was to enhance the mechanical property of chitosan/β-glycerophosphate disodium salt (CS/GP) injectable hydrogels. A novel nanocomposite injectable hydrogel was prepared by introducing attapulgite (ATP) nano particles into the CS/GP hydrogels. The mechanical properties of the composite hydrogels with two different water contents were characterized by tensile test, the results shown that the tensile strength and elongation at break of composite hydrogels both increased obviously with increasing of ATP content. And, in our testing range, the maximum values of tensile strength and elongation at break were both more than 5 times larger than that of neat CS/GP hydrogel. We discussed this enhancement effect in detail by Scanning electron microscope observations (SEM) and Fourier transform infrared spectroscopy testing (FT-IR). The SEM images of composite hydrogels shown quite different from the neat CS/GP hydrogel, where the pores were more tightly and with some uniform and smaller holes dispersed on the wall. FT-IR test results revealed that the introduction of ATP increased the cross-link density because of the hydrogen bonds formation between ATP nanoparticles and CS molecules. Also, we studied the impact of ATP introduction on gelation speed through tracking the dynamic process of the sol–gel transition by means of rheological measurement, and the results shown that the reaction rate increased significantly with the increase of ATP concentration. [ABSTRACT FROM AUTHOR]

Environmental pollution is increasingly becoming a serious global challenge due to various pollutants. Cellulose nanomaterials (CNMs) based membranes originated from green resources and sustainable processes are expected to have great potential in environmental applications due to their nanoscale dimension, high surface area, biodegradability, and biocompatibility as well as renewable capability. To fully unlock this potential, fundamental understandings of the interplay between various tunable parameters of CNMs and the substances to be separated, are required for the rational design and fabrication of CNMs based membranes. This review highlights the recent advances in CNMs membranes for environmental remediation in achieving clean air, water, and green energy. Key parameters that dominate the performances of CNMs membranes are critically assessed. The interactions of CNMs with pollutants, molecules, and ions are analyzed and their selective transport mechanisms in different membrane separation processes are discussed. The challenges and future directions for CNMs membranes are also outlined. [Display omitted] • Recent advances in CNMs membranes for environmental remediation are reviewed. • The versatile applications of CNMs membranes for clean air, water, and energy are highlighted. • The challenges and future directions for CNMs membranes are outlined. [ABSTRACT FROM AUTHOR]

• Metal-alginate fibers were prepared by the metal-calcium coagulation bath. • Metal-alginate fibers improved flame retardancy and mechanical properties. • The valence states of metal ions were not related to the properties of fibers. • FT-IR and 13C CP/MAS NMR were employed to analysis the structure of fibers. In order to improve the mechanical properties of alginate fiber and enrich its application properties, the metal-alginate fibers were produced with wet spinning in the coagulation bath of Zn2+, Ba2+, Cu2+, Al3+ ions blended with Ca2+ ions. FT-IR and 13C NMR were used to characterize the binding mode of alginic acid with metal ions and the arrangement of G and M groups in the molecular chain. The flame retardancy, mechanical and antibacterial properties of metal-alginate fiber were improved, while its water absorption was decreased. The results of Thermogravimetric (TG) and Limiting oxygen index (LOI) showed that the flame retardancy of metal-alginate fibers was better than that of calcium alginate fibers. The combination of metal ions and alginic acid has different improvement effect of mechanical strength and antimicrobial activity against Escherichia coli and Staphylococcus aureus. The multi-functional fiber is expected to be used in medical textiles and new textile fibers. [ABSTRACT FROM AUTHOR]

• Functionalization of CNC with vinyl groups was achieved through grafting γ-MPS. • Acrylic PSA with CNC was synthesized by in-situ semi-continuous seeding emulsion polymerization. • Superior adhesive properties of fCNC/acrylic PSA were obtained. In this work, functionalized cellulose nanocrystal (fCNC) was obtained by the grafting of 3-methacryloxypropyltrimethoxysilane coupling agent (γ-MPS) onto CNC. Then acrylic pressure sensitive adhesive (PSA) incorporated with various contents of CNC or fCNC was successfully synthesized by an in-situ emulsion polymerization, and the effects of CNC or fCNC on the sol molecular weight, latex properties, thermal properties, viscoelastic properties, and adhesive performance of the acrylic PSA were investigated. The results illustrated a coinstantaneous improvement of tack, shear strength and peel strength with increasing the loading of both CNC and fCNC. Interestingly, fCNC showed much more improvement than CNC on adhesive performance of acrylic PSA. The fCNC-1/acrylic PSA showed tack of 27#, shear strength of 70 h, and peel strength of 13.4 N/25mm, which were 12.5%, 4%, and 106% higher than those of CNC-1/acrylic PSA and 35%, 100%, and 163% higher than those of neat acrylic PSA, respectively. The superior adhesive performance of the fCNC/acrylic PSA films was supposed to be attributed to better compatibility and dispersion of fCNC in the acrylic copolymer. Thus, this work presents a feasible strategy for utilization of CNC in adhesives and coatings. [ABSTRACT FROM AUTHOR]

Microbial polysaccharides (MPs) are biopolymers secreted by microorganisms such as bacteria and fungi during their metabolic processes. Compared to polysaccharides derived from plants and animals, MPs have advantages such as wide sources, high production efficiency, and less susceptibility to natural environmental influences. The most attractive feature of MPs lies in their diverse biological activities, such as antioxidative, anti-tumor, antibacterial, and immunomodulatory activities, which have demonstrated immense potential for applications in functional foods, cosmetics, and biomedicine. These bioactivities are precisely regulated by their sophisticated molecular structure. However, the mechanisms underlying this precise regulation are not yet fully understood and continue to evolve. This article presents a comprehensive review of the most representative species of MPs, including their fermentation and purification processes and their biomedical applications in recent years. In particular, this work presents an in-depth analysis into the structure-activity relationships of MPs across multiple molecular levels. Additionally, this review discusses the challenges and prospects of investigating the structure-activity relationships, providing valuable insights into the broad and high-value utilization of MPs. [Display omitted] [ABSTRACT FROM AUTHOR]

Macroalgae are valuable and structurally diverse sources of bioactive compounds among marine resources. The cell walls of macroalgae are rich in polysaccharides which exhibit a wide range of biological activities, such as anticoagulant, antioxidant, antiviral, anti-inflammatory, immunomodulatory, and antitumor activities. Macroalgae polysaccharides (MPs) have been recognized as one of the most promising candidates in the biomedical field. However, the structure-activity relationships of bioactive polysaccharides extracted from macroalgae are complex and influenced by various factors. A clear understanding of these relationships is indeed critical in developing effective biomedical applications with MPs. In line with these challenges and knowledge gaps, this paper summarized the structural characteristics of marine MPs from different sources and relevant functional and bioactive properties and particularly highlighted those essential effects of the structure-bioactivity relationships presented in biomedical applications. This review not only focused on elucidating a particular action mechanism of MPs, but also intended to identify a novel or potential application of these valued compounds in the biomedical field in terms of their structural characteristics. In the last, the challenges and prospects of MPs in structure-bioactivity elucidation were further discussed and predicted, where they were emphasized on exploring modern biotechnology approaches potentially applied to expand their promising biomedical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • 3D printing technology using biopolymers as feedstocks was reviewed. • Lignocellulosic biopolymers for 3D printing application was highlighted. • Strategical development roadmap of biopolymers 3D printing was proposed. • Key challenges and future perspectives of 3D printing biopolymers were identified. Abstract 3D printing enables the complex or customized structures production in high speed and resolution. However, the lack of bio-based materials with user-defined biochemical and mechanical property is a significant barrier that limits the widespread adoption of 3D printing for products fabrication. Development of eco-friendly natural-derived biopolymers for 3D printing technologies and their promising application in different areas are of huge academic, and environmental interests. This paper reviews the state-of-the-art in terms of 3D printing technology using natural-derived feedstocks, including lignocellulose, starch, algae, and chitosan-based biopolymers. Special consideration is given to the development of lignocellulosic materials, i.e. cellulose, hemicellulose, lignin, and their derivatives as 3D printing feedstocks. A strategical development roadmap with identified material property requirements, key challenges, as well as possible solutions was proposed. It serves as guideline aiming to explore natural-derived biopolymers as novel feedstocks for different 3D printing technologies that will be potentially applied in various areas. [ABSTRACT FROM AUTHOR]

Graphical abstract Schematic illustration of the permselectivity mechanism and permeation performances of LIICMs toward Li+. Highlights • A renewable and easy degradable CA/CS hybrid membrane was prepared. • Lithium-ion imprinted composite membrane (LIICM) was prepared via an eco-friendly and facile approach. • The LIICMs exhibited selectivity for Li+ adsorption in the presence of other ions. • The LIICMs exhibited superior reusability and durability. Abstract Lithium resources are attractive for different applications because of their specific properties. Therefore, it is more significant to find a cost-effective and environment-friendly method to selective adsorption and recovery of Li+. In this work, a renewable and easy degradable CA/CS hybrid membrane was modified with polydopamine as adhesion layer to anchored TiO 2. The simple imprinting process could be realized by hydrolysis polymerization. The adsorption process followed Langmuir isotherm model and pseudo-second-order kinetic equation were researched in detail. The results displayed the maximum adsorption capacity is 20.08 mg g−1 for Li+. The selectivity factors of Li+ to Na+, K+, Mg2+ and Ca2+ are 1.78, 2.43, 2.60 and 3.61, respectively, which mainly attributed to imprinting effect. The LIICMs also exhibited the superior reusability and durability. Thus, the LIICMs provide a powerful tool for selective separation and recovery of Li+ from mixed solutions. [ABSTRACT FROM AUTHOR]

The anisotropic features play indispensable roles in regulating various life activities in different organisms. Increasing efforts have been made to learn and mimic various tissues' intrinsic anisotropic structure or functionality for broad applications in different areas, especially in biomedicine and pharmacy. This paper discusses the strategies for fabricating biomaterials using biopolymers for biomedical applications with the case study analysis. Biopolymers, including different polysaccharides, proteins, and their derivates, that have been confirmed with sound biocompatibility for different biomedical applications are summarized, with a special focus on nanocellulose. Advanced analytical techniques for understanding and characterizing the biopolymer-based anisotropic structures for various biomedical applications are also summarized. Challenges still exist in precisely constructing biopolymers-based biomaterials with anisotropic structures from molecular to macroscopic levels and fitting the dynamic processes in native tissue. It is foreseeable that with the advancement of biopolymers' molecular functionalization, biopolymer building block orientation manipulation strategies, and structural characterization techniques, developing anisotropic biopolymer-based biomaterials for different biomedical applications would significantly contribute to a friendly disease-curing and healthcare experience. [Display omitted] [ABSTRACT FROM AUTHOR]

Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects women of reproductive age. Resistant starch can be fermented by gut microbes then produce short-chain fatty acids (SCFAs). It was reported SCFAs might play a key role in gut microbiota-dependent therapy of PCOS. However, the effects of resistant starch on PCOS symptoms have not yet been investigated. Here, maize starch was acylated with specific SCFAs. Our results indicated that acylated starch can release acetate, propionate, and butyrate into the caecum and colon. Treatment with butylated starch (BS) alleviated abnormal ovarian morphology, metabolic disorders, and sex hormone imbalance in letrozole-treated rats, whereas treatment with acetylated starch and propylated starch did not exhibit such effects. Furthermore, BS stimulated the secretion of peptide tyrosine-tyrosine into the serum by activating a G protein-coupled receptor, GPR41, which further affected disease phenotypes. In addition, compared with caecal microbiota, faecal microbiota was more affected by BS. Butyrate-producing microbes were enriched in faeces after BS treatment and may have helped further to relieve PCOS symptoms. [Display omitted] [ABSTRACT FROM AUTHOR]

• Recent advances in stimuli-responsive CNMs are reviewed. • Reversible interactions of CNMs that trigger desired responses are highlighted. • Stimuli-responsive CNMs exhibit great potential as smart materials. Stimuli-responsive cellulose nanomaterials (CNMs), which change their physicochemical properties in response to specific stimuli have recently been in the spotlight. A great deal of effort has been dedicated to developing stimuli-responsive CNMs in the past two decades. However, the majority of stimuli-responsive CNMs were achieved via the introduction of stimuli-responsive moieties rather than taking advantage of their inherent switchable hydrogen bonds, electrostatic interactions, and molecular polarization in CNMs. In this review, recent advances and future perspectives of stimuli-responsive CNMs that exploiting the inherent switchable hydrogen bonds, reversible electrostatic interactions, and tunable polarization are highlighted. The principles for designing and assembling such smart CNMs are summarized. Stimuli-responsive CNMs that are sensitive to the changes in humidity, chemical molecules, pH, pressure, and electricity represent tremendous opportunities for making advances in sensors, actuators, biomedical applications due to their sensitivity, specificity, and stability. Additionally, major challenges and future perspectives of stimuli-responsive CNMs are reported. [ABSTRACT FROM AUTHOR]