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In this study, we conducted in vitro fermentation with infant faecal inocula dominated by Bifidobacterium longum , Bifidobacterium breve , and Bacteroides enterotypes, and assessed the efficacy of the metabolome associated with 2′-fucosyllactose (2′-FL) fermentation on lipopolysaccharide-induced epithelial cell barrier damage on Caco-2 cells. The results revealed that propionate and butyrate were more prominent in the Bacteroides -dominated group, whereas the Bifidobacterium -dominated group was associated with an increased molar fraction of lactate (∼16 m m). Additionally, our study demonstrated that 2′-FL faecal metabolites (FMs) decreased the production of inflammatory cytokines, and promoted tight junction gene expression by inhibiting the TLR4/NF-κB/MLCK signalling pathway and activating the Nrf2/HO-1 pathway. The 2′-FL FMs from Bacteroides -dominated enterotypes had a unique advantage in regulating the TLR4/NF-κB/MLCK signalling pathway, which can be attributed to the effects of propionate and butyrate. [ABSTRACT FROM AUTHOR]

BACKGROUND The growing consumer demand for healthy products has encouraged the development of low‐salt meat products. In this study, to develop low‐salt restructured tilapia (Oreochromis mossambicus) meat products, citric acid was used to improve the properties of restructured tilapia products. RESULTS: In comparison with control restructured fish products (RP) and surimi products (SP), 0.2% citric acid‐treated restructured fish products (RPC) and surimi products (SPC) showed a significant decrease in expressible water and water activity and a remarkable increase in whiteness, dry matter, hardness, chewiness, gumminess, and acceptability. Mechanistic studies suggested that citric acid significantly changed the content of total protein and myofibrillar proteins and promoted degradation of heavy myosin chains. Fourier‐transform infrared and Raman spectra revealed the citric acid‐mediated alteration in the peak intensities of amide I and amide II bands, which changed the secondary structures of RPC and SPC. CONCLUSION: It is feasible to prepare low‐salt restructured tilapia meat products using citric acid, which offers a means of using muscle by‐products and exploiting new functional products with an added commercial value. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The design of porous tissue engineering scaffold with multiscale open-pore architecture (i.e. , bimodal structure) promotes cell attachment and growth, which facilitates nutrient and oxygen diffusion. In this study, a porous poly (butylene succinate) (PBS)/cellulose nanocrystals (CNCs) composite scaffold with a well-defined controllable bimodal open-pore interconnected structure was successfully fabricated. The bimodal open-porous scaffold architecture was designed by synergistic control of temperature variation and a two-step depressurization in a supercritical carbon dioxide (Sc-CO 2) foaming process. The microstructure and properties of the bimodal open-porous PBS/CNCs scaffold, such as morphology, open porosity, hydrophilic and degradation performance, and mechanical compression properties, were analyzed. In the experiments, the scaffold with unimodal pore structure was used for comparison. The results showed that the bimodal open-porous PBS5 scaffold displayed a well-defined bimodal open-pore structure composed of large pore (~68.9 μm in diameter) and small pore (~11.0 μm in diameter), with a high open porosity (~95.2%). In addition, the scaffolds exhibited good mechanical compressive properties (compressive strength of 2.76 MPa at 50% strain), hydrophilicity (water contact angle of 71.7 °C) and in vitro degradation rate. Moreover, in vitro biocompatibility was determined with NIH-3T3 fibroblast cells using MTT assay and live/dead cell viability assay. Results indicated that the obtained bimodal open-porous scaffolds had a good biocompatibility and the viability of cells grown on the scaffolds reached up to 98% after 7th day of culture. Therefore, our work provides new insights into the use of biodegradable polymeric composite scaffolds with bimodal open-pore structure and balanced properties in tissue engineering. [ABSTRACT FROM AUTHOR]

Sensitive and specific detection of protein is of great significance for early diagnosis and prognosis of many diseases. However, great challenges remain unsolved including relative low sensitivity, high cost, long testing time, complicated instrument and laborious operation. To improve the performance of protein detection methods, development of fine reaction interface for recognition and signal amplification is of great importance. In this work, we construct a novel mode of DNA assembly at electrode interface based on a tripodal surface anchor and an electrochemical aptasensor for protein assay is developed. The orientation of the immobilized DNA is optimized, which promises the efficiency of protein recognition. In addition, hybridization chain reaction is employed for further signal amplification. Therefore, this detection method shows high sensitivity with excellent specificity. The strategy can be universally applicable by simply modifying the sequences of used DNA probes. [ABSTRACT FROM AUTHOR]

Rapid occlusion is the culprit leading to implantation failure of biological blood vessels. Although adenosine is a clinical-proven drug to overcome the problem, its short half-life and turbulent burst-release limit its direct application. Thus, a pH/temperature dual-responsive blood vessel possessed controllable long-term adenosine secretion was constructed based on acellular matrix via compact crosslinking by oxidized chondroitin sulfate (OCSA) and functionalized with apyrase and acid phosphatase. These enzymes, as adenosine micro-generators, controlled the adenosine release amount by "real-time-responding" to acidity and temperature of vascular inflammation sites. Additionally, the macrophage phenotype was switched from M1 to M2, and related factors expression proved that adenosine release was effectively regulated with the severity of inflammation. What's more, the ultra-structure for degradation resisting and endothelialization accelerating was also preserved by their "double-crosslinking". Therefore, this work suggested a new feasible strategy providing a bright future of long-term patency for transplanted blood vessels. Biomedical material that can automatically control the release of adenosine to ensure long-term patency of blood vessels after transplantation. [Display omitted] • A novel pH&T dual-responsive OCSA/APY/ACP-dECM blood vessel was prepared. • Inflammatory micro-environment of anastomotic stoma activated the ADO related enzyme. • APY/ACP enzymes ensured ADO release in an appropriate active range (10 nM ∼ 1 mM). • ADO secretion avoided rapid occlusion to ensured long-term patency of blood vessel. [ABSTRACT FROM AUTHOR]

Targeted drug delivery for cancer therapy is expected to enhance therapeutic efficacy with minimized side effects, where the ligand-receptor recognition serves as a common targeting approach. Various ligands have been reported and carbohydrates, one of the crucial structures of tumor cell membranes, have been demonstrated effective for cell-selective binding. Hence, glycosylation-mediated cancer-targeted drug nanocarriers have received increasing attention in recent years. This review surveys a variety of glycosylated drug delivery systems as well as their applications for cancer therapy. Their challenges, opportunities, and future perspectives are also discussed in the end. [ABSTRACT FROM AUTHOR]

To enhance implant stability and prolong the service life of artificial joint component, a new approach was proposed to improve the wear resistance of artificial joint component and endow artificial joint component with the biological efficacy of resistance to aseptic loosening. Strontium calcium polyphosphate (SCPP) were interfused in ultrahigh molecular weight polyethylene (UHMWPE) by a combination of liquid nitrogen ball-milling and flat-panel curing process to prepare the SCPP/UHMWPE composites. The micro-structure, mechanical characterization, tribological characterization and bioactivities of various SCPP/UHMWPE composites were investigated. The results suggested that this method could statistically improve the wear resistance of UHMWPE resulting from a good SCPP particle dispersion. Moreover, it is also observed that the SCPP/UHMWPE composites-wear particles could promote the production of OPG by osteoblasts and decrease the production of RANKL by osteoblasts, and then increase the OPG/RANKL ratio. This indicated that the SCPP/UHMWPE composites had potential efficacy to prevent and treat aseptic loosening. Above all, the SCPP/UHMWPE composites with a suitable SCPP content would be the promising materials for fabricating artificial joint component with ability to resist aseptic loosening. [ABSTRACT FROM AUTHOR]

The advantages of bioceramics, such as biocompatibility and osteoconduction, have been widely used for bone repair and substitute as bone tissue-engineering materials. Bioceramic scaffolds however still need improvement to meet the requirements for complex bone repair. The aim of this study was to develop novel bioscaffolds for bone regeneration, based on the combination of silk fibroin (SF) and calcium polyphosphate (CPP) composite scaffolds. In this study, Bombyx mori silk fibroin (BMSF) and Antheraea pernyi silk fibroin (APSF) were prepared, and applied into CPP scaffolds with glutaraldehyde crosslinking to form the BMSF/CPP and APSF/CPP bioceramics. These scaffolds were then undergone the strength tests, morphology evaluation, and assessments for biodegradation and biocompatibility. Our results showed that the CPP-type bioceramics presented a higher compressive strength and enhanced degradation after the silk fibroin was doped into a CPP structure. Moreover, the BMSF/CPP and APSF/CPP-type scaffolds exhibited lower cellular toxicity than those of the CPP and HA types. Considering the improved mechanical characteristics and degradation as well as ready availability, SF/CPP may be considered a suitable bioceramic for bone tissue-engineering. [ABSTRACT FROM AUTHOR]

Biological tissue-derived biomaterials must be chemically modified to avoid immediate degradation and immune response before being implanted in human body to replace malfunctioning organs. DAS with active aldehyde groups was employed to replace glutaraldehyde (GA), a most common synthetic crosslinking reagent in clinical practice, to fix bioprostheses for lower cytotoxicity. The aim of this research was to evaluate fixation effect of DAS. The tensile strength, crosslinking stability, cytotoxicity especially the anti-calcification capability of DAS-fixed tissues were investigated. The tensile strength and resistance to enzymatic degradation of samples were increased after DAS fixation, the values maintained stably in D-Hanks solution for several days. Meanwhile, ultrastructure of samples preserved well and the anti-calcification capability of samples were improved, the amount of positive staining points in the whole visual field of 15% DAS-fixed samples was only 0.576 times to GA-fixed ones. Moreover, both unreacted DAS and its hydrolytic products were nontoxic in cytotoxicity study. The results demonstrated DAS might be an effective crosslinking reagent to fix biological tissue-derived biomaterials in tissue engineering. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this work was to prepare chitosan/silk fibroin (CS/SF) blending membranes crosslinked with alginate dialdehyde (ADA) as wound dressings and to evaluate the physical properties and biocompatibility of the membranes. The morphology of membrane was observed by scanning electron microscopy (SEM) which showed that the well consistency of these two compositions. Further, the stability, water absorption and water vapor permeability of the ADA fixed CS/SF membranes could meet the needs of wound dressing. Furthermore, the biocompatibility of ADA fixed membranes was investigated by MTT assays and SEM in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that ADA fixed CS/SF blending membranes with a suitable ratio could be a promising candidate for wound healing applications. [Copyright &y& Elsevier]

Abstract: The development of suitable bioactive three-dimensional scaffold for the promotion of bone regeneration is critical in bone tissue engineering. The purpose of this study was to investigate in vivo osteogenesis of the porous strontium-doped calcium polyphosphate (SCPP) scaffolds for bone repair, as well as the relationship between osteogenic properties of SCPP scaffolds and the secretion of bFGF and VEGF from osteoblasts stimulated by SCPP. Besides, the advantages of scaffolds seeded with mesenchymal stem cells (MSCs) for bone repair were also studied. Firstly, the bone repair evaluation of scaffolds was performed on a rabbit segmental bony defects model over a period of 16weeks by histology combined with X-ray microradiography. And then, in order to avoid the influence from the other factors such as hypoxia which emerge in vivo study and affect the secretion of VEGF and bFGF from host cells, human osteoblast-like cells (MG63) were seeded to SCPP, CPP and HA scaffolds in vitro to determine the ability of these scaffolds to stimulate the secretion of angiogenic growth factors (VEGF and bFGF) from MG63 and further explore the reason for the better osteogenic properties of SCPP scaffolds. The histological and X-ray microradiographic results showed that the SCPP scaffolds presented better osteogenic potential than CPP and HA scaffolds, when combined with MSCs, the SCPP scaffolds could further accelerate the bone repair. And the amounts of VEGF measured by ELISA assay in SCPP, CPP and HA groups after cultured for 7days were about 364.989pg/mL, 244.035pg/mL and 232.785pg/mL, respectively. Accordingly, the amounts of bFGF were about 27.085pg/mL, 15.727pg/mL and 8.326pg/mL. The results revealed that the SCPP scaffolds significantly enhanced the bFGF and VEGF secretion compared with other scaffolds. The results presented in vivo and in vitro study demonstrated that the SCPP could accelerate bone formation through stimulating the secretion of VEGF and bFGF from osteoblasts, making it attractive for bone regeneration. [Copyright &y& Elsevier]

Intact cells, as the smallest unit of whole foods, were isolated from three legume crops and fermented with human faecal inoculum to elucidate the effect of food macro-nutrients compositional difference (starch, proteins and lipids) on in vitro colonic fermentation profiles. After 48 h of fermentation, the highest production of short-chain fatty acids (SCFAs) were observed for the pea cells, abundance in starch (64.9 %, db). In contrast, branch chain fatty acids (BCFAs) were the major metabolites for protein-enriched soybean cells (protein content 56.9 %, db). The peanut cells rich in lipids (49.2 %, db) has the lowest fermentation rate among the three varieties. Correspondingly, pea cells favoured the growth of Bifidobacterium , whereas soybean and peanut cells promoted an abundance of Bacteroides and Shigella, respectively. Furthermore, except the intact pea cells promoting the abundance of butyrate producer Roseburia , a similar fermentation pattern was found between intact and broken cells suggesting that macro-nutrient types, rather than structure, dominate the production of metabolites in colonic fermentation. The findings elucidate how the food compositional difference can modulate the gut microbiome and thus provide the knowledge to design whole food legumes-based functional foods. [Display omitted] • Content of starch, proteins and lipids in legume cells determines the colonic microbiota community. • Cell integrity has less effect on modulating in vitro colonic fermentation properties. • Intactness of pea cells can promote the growth of Roseburia associated with increased butyrate production. [ABSTRACT FROM AUTHOR]

Abstract: In this study, porcine aortic tissues were fixed with genipin to construct an esophageal prosthesis. In vitro characterization was performed and in vivo biocompatibility experiments were undertaken to evaluate the biological properties of genipin-fixed porcine aortic tissues. The porcine aortic tissues fixed with genipin at pH 4.0, 0.625g/100ml initial fixative concentrations for 7days showed more favorable characteristics. It was characterized by low antigenicity, good epithelial cellular compatibility, favorable biomechanical properties for an esophageal prosthesis, high resistance against enzymatic degradation and be readily available. The porcine aortic tissues fixed with genipin also showed good biocompatibility in vivo. The present study demonstrated that the genipin-fixed porcine aortic tissues could be a promising material for the construction of an esophageal prosthesis or fabricating scaffold for a tissue engineered esophagus. [Copyright &y& Elsevier]

• The reductions of mucin and TJs protein will accelerate the development of IBD. • TH-GLs inhibits the NF-κB and TNF signaling pathway to regulate the response to UC. • TH-GLs increases secretion of MUC2, improved the mucosal barrier function. • TH-GLs provides ideas for the development of nutritional drugs for IBD. The purpose of this study was to evaluate the relieving effect of tilapia head glycolipids (TH-GLs) on dextran sulfate sodium (DSS)-induced colitis in mice and to further explore its mechanism. Mice were orally administered 3% (w/v) DSS to establish a model of ulcerative colitis (UC), and subsequently treated with TH-GLs or sulfasalazine. In addition, the expression of key targets in the intestinal mucosal barrier and the inflammatory signal pathway were studied by combining immunochemical analysis techniques. The results showed that varying doses of TH-GLs can significantly improve colon lesions caused by DSS, reduce histological scores, increase mucus secretion, extend colon length, increase weight, and inhibit the occurrence of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), Interleukin-1β (IL-1β), and Interleukin- 6 (IL-6). Further, studies have shown that TH-GLs increase the secretion of MUC2 and up-regulate the expression of tight junction related proteins, such as ZO-1 and Occludin. In addition, TH-GLs significantly down-regulated the protein expression levels of TNF-α, IKK-β, and nuclear factor-κB (NF-κB). Here, we have elucidated the potential mechanism of TH-GLs in protecting mice with colitis. In general, this study shows that TH-GLs could improve the symptoms of UC by improving the gut barrier and inhibiting inflammatory signals, which provides a scientific basis for future clinical applications. [ABSTRACT FROM AUTHOR]

• A novel acid-responsive F127-DA/nano-CaCO 3 composite hydrogel was fabricated. • Acid treatment leaded to space-controlled distribution of nano-CaCO 3 in a hydrogel. • Space-controlled distribution of nano-CaCO 3 in a hydrogel improved its mechanical properties. • Space-controlled distribution of nano-CaCO 3 in F127-DA hydrogel was beneficial to the expression of osteogenic factors. • The composite hydrogel platform performed well in bone regeneration. Many hydrogel scaffolds for bone regeneration do not satisfy clinical needs due to uncontrollable mechanical properties and calcium supply and a lack of outstanding osteogenic functions. Herein, a novel acid-responsive composite hydrogel scaffold platform was developed to provide controllable stiffness and calcium supply for enhanced bone regeneration. For this purpose, pluronic F127 diacrylate (F127-DA) was selected as the model scaffold matrix material due to its good biocompatibility and easy formulation capability. Nano-CaCO 3 was chosen as the composite material to provide an acid-responsive property and controlled calcium supply. The acid-responsive nano-CaCO 3 may lead to space-controlled distribution of nano-CaCO 3 in a hydrogel under acid treatment, leading to effective regulation of the mechanical properties of the hydrogel scaffold. Furthermore, the hydrogel may efficiently modulate the expression of Col1, BMP2 and OPN, which are beneficial for osteogenesis. In vivo studies in a rabbit skull bone defect model indicated that this F127-DA/nano-CaCO 3 composite hydrogel platform performed better in bone regeneration than a pure F127-DA hydrogel. Therefore, this responsive composite hydrogel platform provides a simple and robust strategy for developing advanced composite hydrogel scaffolds for effective bone repair. [ABSTRACT FROM AUTHOR]

Natural evolution has nurtured a series of active molecules that play vital roles in physiological systems, but their further applications have been severely limited by rapid deactivation, short cycle time, and potential toxicity after isolation. For instance, the instability of structures and properties has greatly descended when sanshool is derived from Zanthoxylum xanthoxylum. Herein, natural polyphenols are employed to boost the key properties of sanshool by fabricating a series of nanoparticles (NPs). The intracellular evaluation and in vivo animal model are conducted to demonstrate the decreased photodamage score and skin‐fold thickness of prepared NPs, which can be attributed to the better biocompatibility, improved free radical scavenging, down‐regulated apoptosis ratios, and reduced DNA double‐strand breaks compared to naked sanshool. This work proposes a novel strategy to boost the key properties of naturally occurring active molecules with the assistance of natural polyphenol‐based platforms. [ABSTRACT FROM AUTHOR]

The demand for green and non-toxic hair dyes has continued to grow in recent years as the majority of consumers prefer natural and healthy products. There are a series of pigments in nature that are used for color pigmentation and dyeing, such as melanin in animals and curcumin in plants. Accordingly, these nature-inspired novel hair dyes are recognized as having the potential to replace conventional hair dyes for their bio-friendly and less irritating properties. Although several nature-inspired hair dye products and their potential properties, including antistatic, antioxidant, and antibacterial properties, have been proposed, their complex pigmentation mechanisms are not fully understood. The present feature article covers several nature-inspired pigments and strives to summarize the possible pigmentation mechanisms for hair dyeing. A special focus was given to the color-tuning techniques of these novel hair dyes, such as optimization of polymerization, pigment compounding, and tuning of the energy level structure. [ABSTRACT FROM AUTHOR]

Using three-dimensional (3D) printing technology to make the porous tantalum plate and modify its surface. The physicochemical properties, cytocompatibility, antioxidant capacity, and histocompatibility of the modified materials were evaluated to prepare for the repair of craniomaxillofacial bone defects. The porous tantalum plates were 3D printed by selective laser melting technology. Tantalum plates were surface modified with a metal polyphenol network. The surface-modified plates were analyzed for cytocompatibility using thiazolyl blue tetrazolium bromide and live/dead cell staining. The antioxidant capacity of the surface-modified plates was assessed by measuring the levels of intracellular reactive oxygen species, reduced glutathione, superoxide dismutase, and malondialdehyde. The histocompatibility of the plates was evaluated by animal experiments. The results obtained that the tantalum plates with uniform small pores exhibited a high mechanical strength. The surface-modified plates had much better hydrophilicity. In vitro cell experiments showed that the surface-modified plates had higher cytocompatibility and antioxidant capacity than blank tantalum plates. Through subcutaneous implantation in rabbits, the surface-modified plates demonstrated good histocompatibility. Hence, surface-modified tantalum plates had the potential to be used as an implant material for the treatment of craniomaxillofacial bone defects. [ABSTRACT FROM AUTHOR]

Poor prognosis is often expected after the treatment of intracerebral haemorrhage (ICH) when the approach lacks effective neuroprotective interventions. Minocycline (Mino) is a promising clinical neuroprotective candidate for acute ICH therapy that mainly inhibits activation of microglia/macrophages. However, to address iron neurotoxicity, ferroptosis, and oxidative stress‐induced multiple neuroinjury mechanisms, the neuroprotective effect of minocycline still urgently needs to be enhanced. To address this issue, procyanidins (PACs), typical natural polyphenols, is used to improve the neuroprotective effect of Mino by constructing PACs‐Mino nanoparticles (NPs) using 3‐aminophenylboronic acid as the crosslinker. The yielding NPs possessed improved antioxidant and iron‐removing capacities in vitro. More importantly, PACs‐Mino NPs exerted excellent therapeutic effects on ICH, showing improved neuroprotective activity and resulting in neurobehavioral recovery, in an in vitro cellular model and an in vivo ICH rat model. This study can provide a general strategy that uses natural polyphenols to boost the performance of drugs for ICH treatment, and the results may be further extended to other injuries of the central nervous system, such as brain injury and spinal cord injury. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have emerged as a promising class of zero-dimensional (0D) carbon nanomaterials due to their outstanding photoluminescence and electrical properties, along with their non-toxic, non-hazardous, and biocompatible advantages. These unique properties have sparked considerable interest in their applications in various fields. The utilization of biomass and plastic wastes as carbon sources to prepare CDs has become a significant area of research interest in recent years, driven by the increasingly strict environmental regulations and the growing volume of waste generated during production processes. In this context, a comprehensive and timely review of the fabrication, structures, properties, and applications of biomass and plastic wastes-derived CDs would significantly expand this field of research. Here, we present an overview of the fabrication methods of biomass and plastic wastes-derived CDs, employing either a top-down or bottom-up strategy. Furthermore, the most recent advances in the structures and properties of these CDs are highlighted and their utilization in polymer composites derived from biomass and plastic wastes are critically reviewed and summarized. Finally, the pending challenges and prospects for future research on polymer/biomass and plastic wastes-derived CDs composites for various applications are discussed. [ABSTRACT FROM AUTHOR]

Abstract Three-dimensional (3D) bio-nanocomposite poly (butylene succinate) (PBS)/cellulose nanocrystals (CNC) scaffolds were fabricated by a solvent mixture of chloroform (CF) and methanol (MeOH) via electrospinning technique. Morphological, thermal, mechanical, and hydrophilicity as well as in vitro degradation and biocompatibility properties of the electrospun fibrous bio-nanocomposite scaffolds were investigated. Scanning electron microscopy (SEM) indicated that the average diameter of the electrospun fibers decreased with increase in CNC concentration. The incorporation of CNC not only enhanced the thermostability, and 0.5 wt% and 1 wt% CNC significantly increased the crystallinity of PBS matrix, but also improved the tensile strength, Young's modulus and hydrophilicity of PBS matrix with an optimum 3 wt% CNC. Moreover, it also improved the porosity and decreased the density of the PBS/CNC scaffolds. In vitro degradation results showed that PBS/CNC3 scaffold had better bio-degradation ability, from 4.5% of neat PBS to 13.74% of PBS/CNC3 in 28 days. 3T3 fibroblast cell culture was performed to confirm the good biocompatibility of the scaffolds. Cells were found to proliferate better on the PBS/CNC3 scaffolds, as compared to neat PBS scaffolds in 7 days. Highlights • PBS/CNC bio-nanocomposite scaffolds were prepared via electrospinning. • The addition of CNC enhanced strength and hydrophilicity of the scaffolds. • The incorporation of CNC improved the in vitro degradation rate of the scaffolds. • 3T3 Fibroblast cell culture verified the scaffolds' biocompatibility. [ABSTRACT FROM AUTHOR]

Bacterial infections represent one of the serious human healthcare threats, and ≈80% of bacterial infections are related to biofilm. So far, there are extensive investigations on the development of robust biomaterials toward the elimination of biofilms and synergistic antibacterial applications. Despite the progress made, concerns have always been raised regarding the sophisticated synthesis and pre‐modification of hybrid materials, complicated purification and high‐cost work. In this study, a series of robust and integrative nanoparticles (NPs) assembled from two types of natural building blocks (natural polyphenols and tobramycin antibiotics) is successfully fabricated via a one‐pot integration approach, which can efficiently destruct the biofilm structure and kill bacteria via enhanced antibiotic infiltration. Notably, natural polyphenols and tobramycin can release from the formed NPs in an on‐demand manner in the bacterial‐induced environment. The former ones can inhibit quorum sensing within bacteria through competitive combination with autoinducer‐2 (AI‐2) to remove the existing biofilm, and the latter antibiotics exert high antibacterial activity both in vitro and in vivo. This study provides new inspirations toward robust and synergistic antimicrobial and antibiofilm nanomaterials via the facile integration of naturally occurring molecules. [ABSTRACT FROM AUTHOR]

Despite its crucial role in directing cell fate in healthy and diseased tissues, improvements in physical-chemical properties and biocompatibility of type-I collagen are still needed. In this report, we described combined and facile method to modify collagen. The collagen film was first modified by procyanidins solution, in which, then subjected to further crosslinked by dialdehyde alginate, resulting in collagen-procyanidins-dialdehyde alginate film. The properties of the crosslinked collagen films were investigated and the results were discussed. Results from differential scanning calorimetry and thermo gravimetric analysis suggested that the thermal stabilities of the collagen-procyanidins-dialdehyde alginate film were significantly improved. The mechanical properties of collagen-procyanidins-dialdehyde alginate film in terms of elongation at break and tensile strength increased approximately 2-fold and 3-fold, respectively compare to pure collagen film. In addition, the resistance to collagenase degradation of collagen-procyanidins-dialdehyde alginate film was remarkably promoted. The results from methyltetrazolium assay and confocal laser scanning microscopy showed that no cytotoxicity of collagen film was introduced by the combined crosslinking method. Thus, the novel combined by procyanidins-dialdehyde alginate crosslinking method shown in this study provided a non-toxic and efficient crosslinking method that improved various properties of collagen film, which has great potential applications in biomedical materials. [ABSTRACT FROM AUTHOR]

Iron-overload diseases are characterized by a variety of symptoms resulting from excessive iron stores, oxidative stress and consequent end-organ damage. Deferoxamine (DFO) is an iron-chelator that can protect tissues from iron-induced damage. However, its application is limited due to its low stability and weak free radical scavenging ability. Herein, natural polyphenols have been employed to enhance the protective efficacy of DFO through the construction of supramolecular dynamic amphiphiles, which self-assemble into spherical nanoparticles with excellent scavenging capacity against both iron (III) and reactive oxygen species (ROS). This class of natural polyphenols-assisted nanoparticles was found to exhibit enhanced protective efficacy both in vitro in an iron-overload cell model and in vivo in an intracerebral hemorrhage model. This strategy of constructing natural polyphenols- assisted nanoparticles could benefit the treatment of iron-overload related diseases with excessive accumulation of toxic or harmful substances. [Display omitted] • Constructing natural polyphenols-based iron chelator nanoparticles. • Facile and universal introduction of different types of natural polyphenols. • Integrating iron chelating and ROS scavenging together. • Not containing useless vectors without therapeutic effect. [ABSTRACT FROM AUTHOR]

Li-doped hydroxyapatite (LiHA) which is prepared through introducing low dose of Li into hydroxyapatite (HA) has been increasingly studied as a bone tissue-engineered scaffold. The degradation properties play a crucial role in the success of long-term implantation of a bone tissue-engineered construct. Herein, the in vitro degradation behaviors of LiHA scaffolds via two approaches were investigated in this study: solution-mediated degradation and osteoblast-mediated degradation. In solution-mediated degradation, after being immersed in simulated body fluid (SBF) for some time, some characteristics of these scaffolds (such as release of ionized lithium and phosphate, pH change, mechanical properties, cytocompatibility and SEM surface characterization) were systematically tested. A similar procedure was also employed to research the degradation behaviors of LiHA scaffolds in osteoblast-mediated degradation. The results suggested that the degradation in SBF and degradation in culture medium with cell existed distinguishing mechanisms. LiHA scaffolds were degraded via a hydrolytic mechanism when they were soaked in SBF. Upon degradation, an apatite precipitation (layer) was formed on the surfaces of scaffolds. While a biological mechanism was presented for the degradation of scaffolds in cell-mediated degradation. Compared with pure HA, LiHA scaffolds had a better effect on the growth of osteoblast cells, meanwhile, the release amount of PO 4 3 − in a degradation medium indicated that osteoblasts could accelerate the degradation of LiHA due to the more physiological activities of osteoblast. According to the results from compressive strength test, doping Li into HA could enhance the strength of HA. Moreover, the results from MTT assay and SEM observation showed that the degradation products of LiHA scaffolds were beneficial to the proliferation of osteoblasts. The results of this research can provide the theoretical basis for the clinical application of LiHA scaffolds. [ABSTRACT FROM AUTHOR]

Although smart bio‐glues have been well documented, the development of internal bio‐glues for non‐invasive or minimally invasive surgery is still met with profound challenges such as safety risk and the lack of deep tissue penetration stimuli for internal usage. Herein, a series of smart internal bio‐glues are developed via the integration of o‐nitrobenzene modified biopolymers with up‐conversion nanoparticles (UCNPs). Upon irradiation by near‐infrared (NIR) light, the prepared smart bio‐glues can undergo a gelation process, which may further induce strong adhesion between tissues under both dry and wet conditions based on multi‐interactions. Moreover, those NIR light‐responsive bio‐glues with deeper tissue penetration ability demonstrate good biocompatibility, excellent hemostatic performance, and the potent ability to accelerate wound healing for both external and internal wounds. This work provides new opportunities for minimally invasive surgery, especially in internal wound healing using smart and robust bio‐glues. [ABSTRACT FROM AUTHOR]

Deferoxamine is commonly used for iron-overload related diseases, its drawbacks such as instability and toxicity, however, significantly limited its utility in clinic. To address these issues, oxidation-responsive alginate-deferoxamine (Alg-DFO) conjugates were synthesized and their structure was characterized. The metabolism studies shown the conjugation of alginate significantly increased the stability of the DFO, with half-life more than 10 times longer than that of the free DFO. Moreover, the conjugates could not only quickly respond to oxidative stimuli and degradation, suggesting their potential to be cleared from the body by responding to iron-overload associated oxidative environment to avoid its accumulation and safety concern, but also protect iron binding capacity of the attached DFO from oxidation. The degradation mechanism for oxidative-response was proposed. In addition, the conjugates shown lower cytotoxicity compared to the free DFO. Taken together, the Alg-DFO conjugates synthesized in this work has promise for treating iron-overload related conditions. [ABSTRACT FROM AUTHOR]

Polyphenolic materials are a class of fascinating and versatile bioinspired materials for biointerfacial engineering. In particular, due to the presence of active chemical groups, a series of unique physicochemical properties become accessible and tunable of the as-prepared polyphenolic platforms, which could delicately regulate the cell activities via cell–material contact-dependent interactions. More interestingly, polyphenols could also affect the cell behaviors via cell–material contact-independent manner, which arise due to their intrinsically functional characteristics (e.g., antioxidant and photothermal behaviors). As such, a comprehensive understanding on the relationship between material properties and desired biomedical applications, as well as the underlying mechanism at the cellular and molecular level would provide material design principles and accelerate the lab-to-clinic translation of polyphenolic platforms. In this review, we firstly give a brief overview of cell hallmarks governed by surrounding cues, followed by the introduction of polyphenolic material engineering strategies. Subsequently, a detailed discussion on cell–polyphenols contact-dependent interfacial interaction and contact-independent interaction was also carefully provided. Lastly, their biomedical applications were elaborated. We believe that this review could provide guidances for the rational material design of multifunctional polyphenols and extend their application window. [ABSTRACT FROM AUTHOR]

0.3Pb(Mg 1/3 Nb 2/3)O 3 -0.7Pb(Zr 0.52 Ti 0.48)O 3 /Pb(Zr 0.52 Ti 0.48)O 3 (PMN-PZT/PZT) piezoelectric films have been deposited on Pt/Ti/SiO 2 /Si substrates via in-situ magnetron sputtering process. The purpose of this work was to investigate heterogeneous interfaces-dependent preferential orientation, micro-morphology, and piezoelectric behaviors of the PMN-PZT/PZT films. Uniform and dense columnar grains are observed by Scanning electron microscope (SEM) analysis as increasing the number of hetero-interfaces. For the film with five heterogeneous interfaces (H5), the superior ferroelectricity (2P r = 21.6 μC/cm2, 2 E c = 60 kV/cm) and dielectricity (ε r = 1012.1, tan δ = 0.022 at 1 kHz) are obtained, which arises from highly dense columnar grain and the influence of heterogeneous interface strain. Moreover, an excellent piezoelectric constant e 31 of 8.2C/m2 is achieved in H5 film, which is 3.5 times larger than that of PZT film. It is expected that this study will simulates the design and synthesis of new functional materials, and provides a guidance for actuators device fabrication and applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] The interaction between ADA and collagen has not been systematically investigated. [•] No extra cytotoxicity was introduced into collagen/ADA membranes. [•] Structure integrity of collagen after ADA treatment is maintained to a large extent. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to scale-up the usage of strontium-doped calcium polyphosphate (SCPP) to major load-bearing applications in bone substitute application. SCPP powders were used to prepare biological coatings on titanium (Ti) substrates by plasma-spraying under a series of different conditions. Microstructure and bonding strength (with titanium substrates) of the SCPP coatings were investigated by an inductively coupled plasma-mass spectrometer, X-ray diffraction analysis, a scanning electron microscope and a strength test machine. The results showed the main crystal type of coating remained β-crystal SCPP. The surface and cross-sectional morphologies of coatings showed that the SCPP coatings were fairly dense. The bonding strength between the SCPP and Ti was higher than normal plasma spraying coatings. Furthermore, the research on the interactions between ROS17/2.5 cells and various SCPP coatings-Ti substrates indicated that the coating-implants possessed good cytocompatibility with osteoblasts. Therefore, SCPP is considered to be a biological coating material with good prospect in clinical application. [Copyright &y& Elsevier]

The development of robust and bioinspired adhesives with excellent performances including fast gel time, low cost, good adhesion strength and stability, and excellent solvent and temperature resistance against harsh environment is urgent for practical applications. In this paper, kinds of natural polyphenolic adhesives have been successfully fabricated via the multiple polyphenol-diisocyanate cross-linking (PDC) reactions between natural polyphenols (extracts) and diisocyanate molecules. Under heating, as-prepared adhesives could effectively adhere onto a wide range of substrates (i.e. PTFE, PET, PMMA, Al, Cu, paper, glass, wood) through hierarchical interactions. Moreover, these adhesives exhibited great adhesion stability against complex solvents and low-temperature environments, whose adhesion strength could remain unchanged after soaking solvents after 30 days, which was conducive to their potential applications in industry and chemical fields, including petroleum, wood, metal, glass, plastics, and rubber adhesion. We believed that this work would provide new strategies towards the preparation of robust adhesives with excellent resistant against various solvents and low temperature for many fields by using naturally occurring building blocks. Natural polyphenolic adhesives were successfully fabricated via the multiple polyphenol-diisocyanate cross-linking (PDC) reactions between natural polyphenols (extracts) and diisocyanate molecules. Under heating, as-prepared adhesives could effectively adhere to a wide range of substrates (i.e. PTFE, PET, PMMA, Al, Cu, paper, glass, wood) through hierarchical interactions. Moreover, these adhesives exhibited great adhesion stability against complex solvents and low-temperature environments, and the adhesion strength could even remain unchanged after soaking solvents after 30 days. [Display omitted] • Natural polyphenolic adhesives were successfully fabricated. • As-prepared adhesives could effectively adhere to various substrates. • These adhesives exhibited great solvents and low-temperature resistance. [ABSTRACT FROM AUTHOR]

Critical success factors for the restoration of jaw defects depend on scaffolds with high levels of osteoconductivity and antimicrobial properties due to the special oral microenvironment. Brushite cement (dicalcium phosphate dihydrate, DCPD) is a bioceramic with good self-setting properties, plasticity, bioabsorbability, and biocompatibility, but with poor osteoconductive and antimicrobial properties. It has been reported that elemental iron doped into DCPD is effective for overcoming this critical deficiency. Herein, iron-doped dicalcium phosphate dihydrate (Fe-DCPD) was prepared and its physicochemical properties characterized. The time required for Fe-DCPD to set was significantly prolonged, and its in vitro degradability increased compared with DCPD. Additionally, the effects of Fe-DCPD on cell adhesion, migration, proliferation, alkaline phosphatase activity, biomineralization, its antimicrobial properties and relative expression of osteogenic genes in MC3T3-E1 cells were evaluated. In addition, the ability to promote restoration of the jaw in vivo was evaluated, to provide the experimental basis for its preclinical application. The incorporation of iron promoted the adhesion, proliferation, and migration of MC3T3-E1 cells, and increased their ALP activity and expression of osteogenic-related genes. Furthermore, both agar plate and broth anti-bacterial tests revealed that Fe-DCPD displayed a significantly greater antibacterial effect on typical Gram-negative and Gram-positive bacteria than DCPD. The in vivo study indicated that Fe-DCPD scaffolds displayed superior antimicrobial and bone repair properties in a rabbit jaw defect. The study established that DCPD doped with iron is a suitable modification for conferring antimicrobial and osteoconductive properties on scaffolds. Thus, the Fe-DCPD scaffold has excellent potential for applications in jaw repair. [ABSTRACT FROM AUTHOR]

Background: During wound healing, the overproduction of reactive oxygen species (ROS) can break the cellular oxidant/antioxidant balance, which prolongs healing. The wound dressings targeting the mitigation of ROS will be of great advantages for the wound healing. puerarin (PUE) and ferulic acid (FA) are natural compounds derived from herbs that exhibit multiple pharmacological activities, such as antioxidant and anti-inflammatory effects. Polydopamine (PDA) is made from natural dopamine and shows excellent antioxidant function. Therefore, the combination of natural antioxidants into hydrogel dressing is a promising therapy for wound healing. Results: Hydrogel wound dressings have been developed by incorporating PUE or FA via PDA nanoparticles (NPs) into polyethylene glycol diacrylate (PEG-DA) hydrogel. This hydrogel can load natural antioxidant drugs and retain the drug in the gel network for a long period due to the presence of PDA NPs. Under oxidative stress, this hydrogel can improve the activity of superoxide dismutase and glutathione peroxidase and reduce the levels of ROS and malondialdehyde, thus preventing oxidative damage to cells, and then promoting wound healing, tissue regeneration, and collagen accumulation. Conclusion: Overall, this triple antioxidant hydrogel accelerates wound healing by alleviating oxidative injury. Our study thus provides a new way about co-delivery of multiple antioxidant natural molecules from herbs via antioxidant nanoparticles for wound healing and skin regeneration. [ABSTRACT FROM AUTHOR]

The production of fluorescent polymer dots (PDs) from biomass compounds usually requires additional toxic reagents or external energy input, due to which the facile and green fabrication strategies are still highly desirable. Herein, we report the general and modular preparation of natural polyphenol-based fluorescent PDs via a one-pot co-polymerization reaction under a mild condition. The use of natural polyphenols as the starting materials has completely prevented the use of organic solvents and harsh chemicals, whereas the high reactivity of natural polyphenols allowed the facile and modular fabrication of fluorescent PDs without any external energy input and sophisticated organic synthesis. The luminescence properties of the resulting PDs were dependent on the structure of natural polyphenols, and it was found that PDs possessed good photostability and biocompatibility. In addition, PDs showed high selectivity towards copper ions among cations, anions, and biomolecules, which were further employed to detect copper ions in living cells and environmental water samples. Thus, this strategy offers a green and facile route for the design and preparation of natural molecule-based PDs for biomedical and environmental applications. [ABSTRACT FROM AUTHOR]

Polydopamine (PDA) is a fascinating bioinspired material for the construction of diverse functional materials. In particular, the growing trend of PDA hydrogels clearly reveals the global significance and the intense interest of scientific research in this field. The abundant functional groups make PDA serve as the important structural units for covalent or/and non-covalent interactions with polymers, and anchoring of transition metal ions for hydrogels formation. With these benefits, PDA not only endows hydrogels with various functions such as adhesion, photothermal effect, ultraviolet protection, antioxidant ability, antibacterial properties, but also has been rapidly incorporated into a wide range of applications across the biomedical, environment, energy, and electronic fields. This review strives to provide a comprehensive overview of the relevant advances in the field of bioinspired PDA hydrogels. We start to introduce the PDA as the structural units in hydrogels and dedicate a lot of space to discuss their design and PDA functions in the hydrogels. Furthermore, these functions would bring about various interesting applications of the hydrogels. Some key issues in this emerging field have been also exhibited into discussion which will inspire our thinking in functional hydrogels design. [Display omitted] [ABSTRACT FROM AUTHOR]

Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nanoparticles, preparing ultrasmall sized (< 6 nm) particles with precisely-defined structures has remained a grand challenge. In this work, we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes (POSS)-based polyphenol nanoparticles (T8-, T10-, and T12-GAPOSS) by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael "click" reactions. Those polyphenol nanoparticles exhibited strong free radical scavenging capacity, good biocompatibility and ability to resist cell oxidative damage, which demonstrated great potentials in inhibiting oxidative stress induced pathologies. [ABSTRACT FROM AUTHOR]

Nanomaterials (NMs) with tubular structures, such as halloysite nanotubes (HNTs), have potential applications in biomedicine. Although the biocompatibility of HNTs has been investigated before, the toxicity of HNTs to blood vessels is rarely systemically evaluated. Herein, we compared the toxicity of HNTs and multi-walled carbon nanotubes (MWCNTs) to human umbilical vein endothelial cells (HUVECs) in vitro and blood vessels of mice in vivo. HUVECs internalized HNTs and MWCNTs, but the uptake of HNTs was not obviously changed by clathrin inhibitor. Exposure to NMs decreased cellular viability, activated apoptotic proteins and up-regulated adhesion molecules, including soluble vascular cell adhesion molecule 1 (sVCAM-1) and VCAM-1. As the mechanisms, NMs decreased NO levels, eNOS mRNA and eNOS/p-eNOS proteins. Meanwhile, NMs promoted intracellular ROS and autophagy dysfunction, shown as decreased protein levels of LC3, beclin-1 and ATG5. The eNOS regulator Kruppel-like factor 4 (KLF4) was inhibited, but another eNOS regulator KLF4 was surprisingly up-regulated. Under in vivo conditions, ICR mice intravenously injected with NMs (50 μg/mouse, once a day for 5 days) showed an increased percentage of neutrophils, monocytes and basophils. Meanwhile, autophagy dysfunction, eNOS uncoupling, activation of apoptotic proteins and alteration of KLF proteins were also observed in mouse aortas. All of the toxic effects were more pronounced for MWCNTs in comparison with HNTs based on the same mass concentrations. Our results may provide novel insights about the toxicity of NMs with tubular structures to blood vessels. Considering the toxicological data reported here, HNTs are probably safer nanocarriers compared with MWCNTs. [ABSTRACT FROM AUTHOR]

To overcome the low mechanical strength and difficult bonding of hydrogels to bones which are the major limitations of hydrogels used in bone-regeneration, a new type of calcium polyphosphate incorporated into bioinspired alginate/polyacrylic acid (CPP/PAA-Alg) hybrid double network (DN) hydrogel with both high strength and enhanced osseointergration was prepared by a two-step polymerization with alginate and polyacrylic acid for bone regeneration. The morphology, mechanical properties, swelling, biocompatibility, osseointegration and osteogenic ability of this CPP/PAA-Alg DN hydrogel were investigated. The results show that CPP/PAA-Alg DN hydrogel with highly porous microstructure possesses high water absorption capacity and highly strength properties which meet the requirements of bone repairing. The results of in vitro studies revealed that the CPP/PAA-Alg DN hydrogels can support the spread of cells and promote the cell proliferation. Animal studies demonstrated that the CPP incorporated would enhance the osseointegration of DN hydrogel with host bone at an early stage after implantation to accelerate the regeneration of bone. This research may provide a new way to develop biocompatible biomaterials with high mechanical strength and good osseointegration to meet the needs of bone regeneration. [ABSTRACT FROM AUTHOR]

This research investigated the effect of different types of plant cell wall fibres, including cereal (i.e. , barley, sorghum, and rice), legume (i.e. , pea, faba bean, and mung bean), and tuber (potato, sweet potato, and yam) cell wall fibres on in vitro faecal fermentation profiles and gut microbiota composition. The cell wall composition, specifically the content of lignin and pectin, was found to have a significant influence on the gut microbiota and fermentation outcomes. Compared with type I cell walls (legume and tuber) which have high pectin content, the type II cell walls (cereal) which are high in lignin but low in pectin had a lower fermentation rates and less short-chain fatty acid production. The redundancy analysis showed samples with similar fibre composition and fermentation profiles clustered together, and the principal coordinate analysis revealed separation among different types of cell walls and closer proximity among the same cell wall types. These findings emphasize the importance of cell wall composition in shaping the microbial community during fermentation and contribute to a better understanding of the relationship between plant cell walls and gut health. This research has practical implications for the development of functional foods and dietary interventions. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract This work aimed to improve yield of collagen from the grass carp skin by employing different strategies (acid-acid method, pepsin-pepsin method and acid-pepsin method, denoted as A-A, P-P, A-P, respectively). And further to conduct quantitative characterization on structural properties, self-assembly kinetics and gelation properties of these collagens. Herein, a two-step collagen extraction method (pepsin-pepsin) was established with the high yield. Meanwhile, structural measurements of high-yield collagen (pepsin-soluble collagen, PSC) and acid-soluble collagen (ASC) indicated that both collagens maintained the typical triple helical conformation of collagen type I. Moreover, the fibrillogenesis tests of PSC and ASC at the various temperatures confirmed that self-assembly were the entropy-driven process. The gelation time of both ASC and PSC was determined by the dynamic time sweep at the different frequencies combined with Winter's criterion. The self-assembly kinetics results showed that fibrillogenesis rate for ASC solution was faster, and more liable to gelation relative to PSC. Mechanical measurements suggested that ASC showed the more resistance ability to deformation than PSC due to more complicated architecture, confirmed by higher fractal dimension. However, the equivalent typical assemblies of PSC to ASC at the various stages can still be expected via controlling incubation time or temperature under the guidance of Arrhenius equation. This study would provide some strategies for achieving maximum utilization of waste biomass and significant insights into the mechanisms underlying the quantitative differences in multiple hierarchy conformation (molecule, fibrillogenesis and hydrogel) of ASC and PSC, which may benefit for subsequent design, development and optimization of collagen-based hydrogels in biomedical industries. Graphical abstract Unlabelled Image Highlights • A quantitative study on multi-hierarchy conformation of ASC and PSC was investigated. • PSC assembly resembling ASC could be expected via controlling external conditions. • A high-yield two-step collagen extraction method (pepsin-pepsin) was established. [ABSTRACT FROM AUTHOR]

The development of hydrogels for bone regeneration has highlighted the challenge that load-bearing hydrogels need to be biocompatible while achieving high strength. Several approaches have been reported to improve the toughness of hydrogels, but achieving high toughness and biocompatibility simultaneously remains a challenge. Here we report a polyacrylic acid/alginate/demineralized bone matrix (PAA/Alg/DBM) hybrid double network hydrogel, which was synthesized by a two-step sequential polymerization with embedded DBM, possessing both high strength and biocompatibility. With the persistence of DBM, it can promote the synthesis of VEGF and bFGF and the ALP activity of MG63 cells on hydrogel. All the results suggest that this hybrid double network hydrogel have potential for future application in bone regeneration. [ABSTRACT FROM AUTHOR]

The elaboration of the rheological behaviors of alginate dialdehyde (ADA) crosslinked collagen solutions, along with the quantitative analysis via numerical models contribute to the controllable design of ADA crosslinked solution system's fluid mechanics performance during manufacturing process for collagen biomaterials. In the present work, steady shear flow, dynamical viscoelasticity, creep-recovery, thixotropy tests were performed to characterize the rheological behaviors of the collagen solutions incorporating of ADA from the different aspects and fitted with corresponding numerical models. It was found that pseudoplastic properties of all samples enhanced with increasing amounts of ADA, which was confirmed by the parameters calculated from the Ostwald-de Waele model, Carreau and Cross model, for instance, the non-Newtonian index (n) decreased from 0.786 to 0.201 and a great increase by 280 times in value of viscosity index (K) was obtained from Ostwald-de Waele model. The forth-mode Leonov model was selected to fit all dynamic modulus-frequency curves due to its higher fitting precision (R 2 > 0.99). It could be found that the values of correlation shear viscosity (η k ) increased and the values of relaxation time (θ k ) decreased with increasing ADA at the fixed k value, suggesting that the incorporation of ADA accelerated the transformation of the collagen solutions from liquid-like to gel-like state due to more formation of C N linkages between aldehyde groups and lysine residues. Also, the curves of creep and recovery phase of the native and crosslinked collagen solutions were simulated well using Burger model and a semi-empirical model, respectively. The ability to resist to deformation and elasticity strengthened for the samples with higher amounts of ADA, accompanied with the important fact that compliance value (J 50 ) decreased from 56.317 Pa − 1 to 2.135 Pa − 1 and the recovery percentage (R creep ) increased from 2.651% to 28.217%. Finally, it was found that the area of thixotropic loop increased from 8.942 Pa/s to 17.823 Pa/s with increasing introduction of ADA, suggesting that stronger thixotropic behavior was associated with higher amount of ADA. Furthermore, Herschel–Bulkley model was employed to describe the up and down curves of all samples and it was confirmed that all collagen solutions belonged to pseudoplastic fluid (the flow index < 1) without apparent yield stress and shear-thinning behaviors were more obvious with increasing additions of ADA according to the increasing consistency coefficient K values. Overall, this work contributed a new insight into the interactions between collagen and ADA based on quantitative rheological methods reflecting the different rheological properties and the results obtained should be of great utility in the extensive application of ADA crosslinked collagen solutions into diverse collagen-based materials. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the crosslinking effect of dialdehyde carboxymethyl cellulose (DCMC) on decellularized porcine aortas. Before implanted, biological tissues must be chemically modified to avoid rapid enzymatic degradation and serious immune response. To overcome limitations like high cytotoxicity and susceptibility to calcification caused by glutaraldehyde (GA), a traditional crosslinking reagent, dialdehyde carboxymethyl cellulose (DCMC) was employed to fix biological tissues. The crosslinking characteristics and cytotoxicity of aortas fixed by DCMC were all investigated. The results indicated that DCMC-fixation significantly increased the mechanical strength and the capacity of enzymatic hydrolytic resistance of tissues. The histological examination showed that the microcosmic structures of tissues were all preserved well after DCMC fixation. In addition, the data obtained from MTT assay confirmed that the cytotoxicity of DCMC-fixed tissues was significantly lower than glutaraldehyde-fixed counterparts. In a word, the present study demonstrated DCMC might be an effective crosslinking reagent for biological tissue fixation with low cytotoxicity. [ABSTRACT FROM AUTHOR]

Abstract: The vascularization of tissue-engineered bone is the key problem needed solving before application of tissue-engineered bone in clinical practice. Meanwhile, endothelial cells are the major and important source of seed cells in bone tissue engineering, and significant on promoting vascularization in tissue-engineered bone. Vascularization (namely angiogenesis) is a process mainly controlled by several angiogenic growth factors (VEGF, bFGF and MMP-2) which can be secreted by endothelial cells. Therefore, the research on the stimulations of SCPP to the secretion of the angiogenic growth factors from endothelial cells is very important. This study was performed to determine the ability of strontium-doped calcium polyphosphate (SCPP) to induce angiogenesis by detecting the protein secretion levels and mRNA expression of VEGF, bFGF and MMP-2 from cultured endothelial cells. As a control, we also researched the effect of HA on the mRNA expressions and protein secretion of angiogenic growth factors from cultured endothelial cells. We cultured endothelial cells with SCPP scaffolds containing various concentration of strontium and HA. The results obtained in the MTT and SEM tests indicated that endothelial cells on SCPP scaffold exhibited higher proliferation rate and were easy to get a good spread than them on CPP, the best state of growth and proliferation of cells could be observed on 8%SCPP. The results of ELISA demonstrated that the protein levels of VEGF, bFGF and MMP-2 from cultured endothelial cells increased with the increasing Sr doped in calcium polyphosphate in SCPP groups, the peaks appeared on 8%SCPP. All SCPP groups showed a better ability to stimulate the protein secretion of VEGF, bFGF and MMP-2 from endothelial cells relative to CPP group and HA group. The results of RT-PCR suggested that the 8%SCPP group exhibited a significantly higher mRNA expression of VEGF, bFGF and MMP-2 relative to CPP group and HA group. In conclusion, the results of this study demonstrated that 8%SCPP had obvious promotion for secretion and mRNA expression of angiogenic growth factors from cultured endothelial cells. [Copyright &y& Elsevier]

Abstract: The critical success factors for bone tissue engineering in clinical applications are scaffolds. Ion doping is one of the most important methods to modify the properties of bioceramics for better angiogenesis abilities, biomechanical properties, and biocompatibility. This paper presents a novel ion doping method applied in calcium polyphosphate (CPP)-based bioceramic scaffolds substituted by strontium ions to form (SCPP) scaffolds for bone tissue regeneration. The microstructure and crystallization of the scaffolds were detected by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Degradation tests were assessed to evaluate the mechanical and chemical stabilities of SCPP in vitro. The cell biocompatibility was measured with respect to the cytotoxicity of the extractions of scaffolds. Bone implantation was performed to evaluate the biodegradability and osteoconductivity of the scaffolds, and the bone formation examined by using X-ray radiography. The results indicated that the obtained SCPP scaffolds had a single CPP phase. The SCPP scaffolds yielded a better degradation property than the pure CPP scaffold. The MTT assay and in vivo results reveal that the SCPP scaffolds exhibited a better cell biocompatibility and tissue biocompatibility than CPP and hydroxyapatite (HA) scaffolds. The in vivo immunohistochemistry staining for VEGF also showed that SCPP had a potential to promote the formation of angiogenesis and the regeneration of bone. SCPP scaffold could serve as a potential biomaterial with stimulating angiogenesis in bone tissue engineering and bone repair. [Copyright &y& Elsevier]

Highlights: [•] We used alginate dialdehyde (ADA) for biological tissue fixation. [•] The degradation of the fixed biological tissues was evaluated thoroughly. [•] The ADA-fixed tissues could degrade gradually over time. [•] It might provide a successful example of the applications in tissue engineering. [•] This is a study which has not been reported elsewhere. [ABSTRACT FROM AUTHOR]

Abstract: Physicochemical properties are considered crucial for porcine acellular dermal matrix (PADM) scaffolds to maintain their native three dimensional structures and special functionalities in clinical applications. In this context, a combined technique of dehydrothermal treatment (DHT) and carbodiimide (EDC) crosslinking was applied to modify PADM scaffolds. Mechanical testing results suggested that crosslinking the scaffolds by DHT+EDC significantly improved the tensile strength of the scaffolds compared to that by either DHT or EDC crosslinking, but decreased the elongation at break slightly. And higher crosslink density and denaturation temperature were found in DHT+EDC group without any collapse in three-dimensional architecture, which may indicate the existence of synergistic effect between DHT and EDC crosslinking on PADM scaffolds. Moreover, PADM scaffolds for DHT+EDC group reflected a reduced degradation rate when they were exposed to bacterial collagenase. Meanwhile, the results obtained in the methyltetrazolium (MTT) study showed that no extra cytotoxicity was induced by DHT+EDC crosslinking on PADM scaffolds which was further confirmed by SEM images. In conclusion, the combined technique of dehydrothermal and carbodiimide treatment in this study has potential for promoting the physicochemical properties of PADM scaffolds for tissue engineering. [Copyright &y& Elsevier]

Abstract: Biological tissues must be chemically fixed before they can be implanted in humans, due to the immediate degradation and presence of antigenicity of naturally derived tissues. To provide a crosslinking reagent which is cytocompatible and may prepare biocompatible fixed tissues, a novel crosslinking agent, alginate dialdehyde (ADA), was employed to fix biological tissues by our group. The study was to evaluate the cytocompatibility of ADA for biological tissue fixation. Glutaraldehyde and genipin counterparts were used as controls. The result suggested that the cytotoxicity of ADA was significantly lower than that of glutaraldehyde and genipin. Additionally, in the evaluation of cytotoxicity of fixed tissue itself and the residues, as well as the cell adhesion property, ADA-fixed tissue was significantly superior to its glutaraldehyde counterpart and comparable to its genipin counterpart. The results obtained in this study demonstrate that ADA is a cytocompatible crosslinking reagent for biological tissue fixation. [Copyright &y& Elsevier]

Abstract: Biological tissues must be chemically fixed before they can be implanted in humans. To overcome the cytotoxicity of the current chemical reagents used to fix bioprostheses, a naturally occurring crosslinking agent, alginate dialdehyde (ADA), was employed to fix biological tissues in this feasibility study. In this work, the crosslinking characteristics and the cytotoxicity of ADA-fixed biological tissues were investigated. The results indicated that ADA-fixed tissues are in possession of the fixation index and mechanical strength comparable to glutaraldehyde-fixed counterparts and superior to polyepoxy-fixed counterparts. The histological examination confirmed that the natural structure of the tissues preserved well after ADA fixation. Moreover, the results obtained in the MTT study further indicated that the cytotoxicity of ADA-fixed tissues was significantly lower than that of glutaraldehyde-fixed and polyepoxy-fixed tissues. In conclusion, the results of this vitro study demonstrate that ADA is an effective agent in the fixation of biological tissue. [Copyright &y& Elsevier]