查找使用阿拉丁产品的科研文献

Olive oil-in-water high internal phase Pickering emulsions stabilized by hydroxyapatite nanoparticles

Xinyue Zhang,Haojie Zhang,Wuyi Luo,Jianzhong Jiang

Biocompatible high internal phase emulsions (HIPEs) have attracted much attention in food and cosmetics due to their unique properties, such as adjustable viscoelasticity, high nutrient load, and long shelf life. Herein, we report an olive oil-in-water high internal phase Pickering emulsion (HIPE) stabilized solely by bare hydroxyapatite (HA) nanoparticles. Compared with other HIPEs, the HIPEs stabilized by HA nanoparticles could be obtained through a one-step emulsification method without chemical modification or other chemical additives. The increase of HA concentration (≥ 0.5 wt%) resulted in increases in both the storage modulus and loss modulus of the HIPEs, indicating the particle network plays an essential role in the HIPEs gel strength. After increasing the oil phase fraction from 80% to 90%, the viscosity of the HIPEs increased from 8316 to 13855 Pa⋅s (shear rate 0.004 s−1) and exhibited as a pseudoplastic fluid. The effect of oil type on the HIPEs was also investigated. The HA nanoparticles may interact with the olefin and carbonyl groups of olive oil, forming interfacial-active particles to stabilize the HIPEs. This method is universal as it occurs with other natural oils (soybean, sunflower, and fish oil), which may have various applications in food, cosmetics, and functional material fields.

Catalytic Conversion of Sugars into Lactic Acid via a RuOx/MoS2 Catalyst

Zongling Li,Pengfei Wu,Jifeng Pang,Xianquan Li,Shangru Zhai,Mingyuan Zheng

The catalytic transformation of sugars into lactic acid has shown great potential for the scalable utilization of renewable biomass. Herein, RuOx/MoS2catalysts were synthesized with the assistance of CaO for the one-pot conversion of glucose to lactic acid. Under the reaction conditions of 120 °C and 1 MPa O2, a 96.6% glucose conversion and a 54.3% lactic acid selectivity were realized in the one-pot catalytic reaction, with relatively high stability after four successive cycles. This catalytic system was also effective for the conversion of many other carbohydrate substrates, such as fructose, xylose and cellulose (selectivity 68.9%, 78.2% and 50.6%, respectively). According to catalyst characterizations and conditional experiments, the highly dispersed RuOxspecies on the surface of MoS2, together with OH−, promoted isomerization, retro-aldol condensation, dehydration and hydration reactions, resulting in a relatively high lactic acid yield for sugar conversions.Keywords:glucose;catalyst;lactic acid;ruthenium;calcium

Intraosseous Injection of Calcium Phosphate Polymer-Induced Liquid Precursor Increases Bone Density and Improves Early Implant Osseointegration in Ovariectomized Rats

Yanyan Zhou,Zihe Hu,Mingjie Ge,Wenjing Jin,Ruikang Tang,Qi Li,Weijian Xu,Jue Shi,Zhijian Xie

Efficient synthesis of furfurylamine from biomass via a hybrid strategy in an EaCl:Gly–water medium

He Wei,He Yu-Cai,Ye Jianren

The objective of this work was to develop an efficient approach for chemoenzymatically transforming biomass to furfurylamine by bridging chemocatalysis and biocatalysis in a deep eutectic solvent of EaCl:Gly–water. Using hydroxyapatite (HAP) as support, heterogeneous catalyst SO42−/SnO2–HAP was synthesized for transforming lignocellulosic biomass into furfural using organic acid as a co-catalyst. The turnover frequency (TOF) was correlated with the pKa value of the used organic acid. Corncob was transformed by oxalic acid (pKa = 1.25) (0.4 wt%) plus SO42−/SnO2–HAP (2.0 wt%) to produce furfural with a yield of 48.2% and a TOF of 6.33 h-1 in water. In deep eutectic solvent EaCl:Gly–water (1:2, v/v), co-catalysis with SO42−/SnO2–HAP and oxalic acid was utilized to transform corncob, rice straw, reed leaf, and sugarcane bagasse for the production of furfural with the yield of 42.4%–59.3% (based on the xylan content) at 180°C after 10 min. The formed furfural could be efficiently aminated to furfurylamine with E. coli CCZU-XLS160 cells in the presence of NH4Cl (as an amine donor). As a result of the biological amination of furfural derived from corncob, rice straw, reed leaf, and sugarcane bagasse for 24 h, the yields of furfurylamine reached >99%, with a productivity of 0.31–0.43 g furfurylamine per g xylan. In EaCl:Gly–water, an efficient chemoenzymatic catalysis strategy was employed to valorize lignocellulosic biomass into valuable furan chemicals.

Gallic acid-grafted chitosan antibacterial hydrogel incorporated with polydopamine-modified hydroxyapatite for enhancing bone healing

Pang Yuxuan,Guan Lin,Zhu Yanlin,Niu Ruijuan,Zhu Song,Lin Quan

An open critical-size bone defect is a major medical problem because of the difficulty in self-healing, leading to an increased risk of bacterial infection owing to wound exposure, resulting in treatment failure. Herein, a composite hydrogel was synthesized by chitosan, gallic acid, and hyaluronic acid, termed “CGH.” Hydroxyapatite was modified with polydopamine (PDA@HAP) and introduced to CGH to obtain a mussel-inspired mineralized hydrogel (CGH/PDA@HAP). The CGH/PDA@HAP hydrogel exhibited excellent mechanical performances, including self-healing and injectable properties. Owing to its three-dimensional porous structure and polydopamine modifications, the cellular affinity of the hydrogel was enhanced. When adding PDA@HAP into CGH, Ca2+ and PO43- could release and then promoted differentiation of BMSCs into osteoblasts. Without any osteogenic agent or stem cells, the area of new bone at the site of defect was enhanced and the newly formed bone had a dense trabecular structure after implanting of the CGH/PDA@HAP hydrogel for 4 and 8 weeks. Moreover, the growth of Staphylococcus aureus and Escherichia coli was effectively inhibited through the grafting of gallic acid onto chitosan. Above, this study provides a reasonable alternative strategy to manage open bone defects.

Strontium Ion-Functionalized Nano-Hydroxyapatite/Chitosan Composite Microspheres Promote Osteogenesis and Angiogenesis for Bone Regeneration

Dawei Cheng,Ruyuan Ding,Xin Jin,Yifan Lu,Weimin Bao,Yang Zhao,Shi Chen,Cailiang Shen,Qing Yang,Yuanyin Wang

Critical-size bone defects are an important problem in clinical practice, which usually occurs in severe trauma, or tumor resection, and cannot heal completely and autonomously. Implantation of grafts is often required to promote the regeneration of critical-size bone defects. Metal ions play an important role in human health, as they affect the body’s metabolism and the tissue function. Strontium ions (Sr2+) can promote osteogenesis and angiogenesis. Herein, we prepared nano-hydroxyapatite (nHA)/chitosan (CS) composite microspheres with a uniform particle size distribution and an extracellular matrix-like nanofiber structure using microfluidic technology and direct alkali-induced gelation. Strontium ions were stably added into the microspheres by using polydopamine (PDA) to chelate metal ions forming a bone repair material (nHA/CS@PDA-Sr) with good bioactivity. The coordination reaction of PDA can effectively control the release of strontium ions and avoid the negative effects caused by the high strontium concentration. Our in vitro experiments showed that the composite microspheres had good biocompatibility and that the PDA coating promotes cell adhesion. The slow release of strontium ions can effectively promote mesenchymal stem cells osteogenic differentiation and the vascularization of endothelial cells. In addition, we injected composite microspheres into cranial defects of rats to evaluate osseointegration in vivo. The results showed that nHA/CS@PDA-Sr could effectively promote bone regeneration in the defect area. This study demonstrates that composite microspheres stimulate bone repair providing a promising way for bone-defect regeneration.

Polydopamine-coated biomimetic bone scaffolds loaded with exosomes promote osteogenic differentiation of BMSC and bone regeneration

Yi Zhou,Guozhen Deng,Hongjiang She,Fan Bai,Bingyan Xiang,Jian Zhou,Shuiqin Zhang

Introduction The repair of bone defects is ideally accomplished with bone tissue engineering. Recent studies have explored the possibility of functional modification of scaffolds in bone tissue engineering. We prepared an SF-CS-nHA (SCN) biomimetic bone scaffold and functionally modified the scaffold material by adding a polydopamine (PDA) coating loaded with exosomes (Exos) of marrow mesenchymal stem cells (BMSCs). The effects of the functional composite scaffold (SCN/PDA-Exo) on BMSC proliferation and osteogenic differentiation were investigated. Furthermore, the SCN/PDA-Exo scaffolds were implanted into animals to evaluate their effect on bone regeneration. Methods SCN biomimetic scaffolds were prepared by a vacuum freeze-drying/chemical crosslinking method. A PDA-functionalized coating loaded with BMSC-Exos was added by the surface coating method. The physical and chemical properties of the functional composite scaffolds were detected by scanning electron microscopy (SEM), energy spectrum analysis and contact angle tests. In vitro, BMSCs were inoculated on different scaffolds, and the Exo internalization by BMSCs was detected by confocal microscopy. The BMSC proliferation activity and cell morphology were detected by SEM, CCK-8 assays and phalloidin staining. BMSC osteogenic differentiation was detected by immunofluorescence, alizarin red staining and qRT‒PCR. In vivo, the functional composite scaffold was implanted into a rabbit critical radial defect model. Bone repair was detected by 3D-CT scanning. HE staining, Masson staining, and immunohistochemistry were used to evaluate bone regeneration. Results Compared with the SCN scaffold, the SCN/PDA-Exo-functionalized composite scaffold had a larger average surface roughness and stronger hydrophilicity. In vitro, the Exos immobilized on the SCN/PDA-Exo scaffolds were internalized by BMSCs. The BMSC morphology, proliferation ability and osteogenic differentiation effect in the SCN/PDA-Exo group were significantly better than those in the other control groups (p < 0.05). The effects of the SCN/PDA-Exo functional composite scaffold on bone defect repair and new bone formation were significantly better than those of the other control groups (p < 0.05). Conclusions In this study, we found that the SCN/PDA-Exo-functionalized composite scaffold promoted BMSC proliferation and osteogenic differentiation in vitro and improved bone regeneration efficiency in vivo. Therefore, combining Exos with biomimetic bone scaffolds by functional PDA coatings may be an effective strategy for functionally modifying biological scaffolds.

Amyloid-Mediated Nanoarchitectonics with Biomimetic Mineralization of Polyetheretherketone for Enhanced Osseointegration

Yingtao Gao,Yanyun Pang,Shuo Wei,Qian Han,Shuting Miao,Min Li,Juanhua Tian,Chengyu Fu,Zhengge Wang,Xu Zhang,Peng Yang,Yongchun Liu

Polyetheretherketone (PEEK), a widely used implant material, has attracted the attention of scientific researchers because of its bone-matched elastic modulus, radiolucency, and chemical resistance. However, the bioinert chemical properties of PEEK do not promote bone apposition once implanted. In this study, using a phase-transitioned lysozyme (PTL) nanofilm as a sandwiched layer, a robust hydroxyapatite (HAp) coating on PEEK (HAp@PTL@PEEK) is constructed. The PTL nanofilm shows strong adhesion to the PEEK surface and induces biomimetic mineralization to form a compact HAp coating on PEEK in simulated body fluids. This HAp coating not only shares a higher adhesion strength and better stability but can also be applied to implants with complex 3D structures. HAp@PTL@PEEK showed significantly enhanced osteogenic capacity when cultured with rat bone marrow mesenchymal stem cells by promoting initial cell adhesion, proliferation, and osteogenic differentiation in vitro. In vivo evaluations utilizing models of femoral condyle defects and skull defects confirm that the HAp coating substantially augments bone remodeling and osseointegration ability. Compared with the traditional method, our modified method is simpler, more environmentally friendly, and uses less hazardous components. Furthermore, the obtained HAp coating shares a higher adhesion strength to PEEK and a better osteogenic capacity. The study offers a novel method to improve the osseointegration of PEEK-based implants in biointerfaces and tissue engineering.

Preparation and properties of homogeneous oxidized sodium alginate/silica/polyacrylamide–gelatin composite hydrogel based on interpenetrating network technology

Li Dongze,Liao Yuqing,Chen Xiuqiong,Wang Hongcai,Wen Yanshi,Cheng Kaiyue,Chen Weiwei,Yan Huiqiong,Lin Qiang

To address the functional defect of alginate hydrogel in tissue engineering applications, we adopted the interpenetrating polymer network technology as well as the incorporation of SiO 2 nanoparticles and the surface coverage of gelatin to fabricate homogeneous oxidized sodium alginate/silica/polyacrylamide–gelatin (OSA/SiO 2 /PAM-GT) composite hydrogels, using hydroxyapatite/D-glucono-δ-lactone (HAP/GDL) complex as the gelling system. Specially, the effect of SiO 2 nanoparticles on the microstructure, mechanical properties, in vitro swelling, biodegradability, biomineralization and biocompatibility of the composite hydrogels was investigated. The resultant OSA/SiO 2 /PAM-GT composite hydrogels exhibited relatively regular 3D morphology with well-developed pore structure with HAP/GDL as the cross-linking agents. The incorporation of SiO 2 nanoparticles could effectively regulate the pore structure, mechanical properties, swelling ratio, in vitro biodegradability and biomineralization of OSA/SiO 2 /PAM-GT composite hydrogels. Meanwhile, the OSA/SiO 2 /PAM-GT composite hydrogels could also support the adhesion, proliferation and differentiation of MG-63 cells, which could be applied to the tissue engineering field.

Pyruvate and lactate based hydrogel film inhibits UV radiation-induced skin inflammation and oxidative stress

Mingsheng Liu,Wenwen Yu,Yu Fang,Haichun Zhou,Yu Liang,Congshu Huang,Hongbin Liu,Guanghui Zhao

Solar skin damage is one of the most common diseases among outdoor workers. An important cause for the damage is the ultraviolet and infrared rays in sunlight, which are absorbed by the skin in large amounts, leading to severe skin inflammation and oxidative stress. Therefore, physical prevention by shielding the light from harmful wavelengths can be an effective method of skin protection from radiation. However, for existing skin lesions, prompt treatment is essential to avoid the aggravation of the injury and promote repair. Therefore, to improve the therapeutic effect on sun-damaged skin, we attempted to design a system with a dual purpose of eliminating toxic free radicals and modulating tissue inflammatory response. Here, we designed and synthesized a poly-acryloyl lysine (P-Ac-Lys) and polyvinyl alcohol-dihydroxyphenylalanine (PVA-DOPA) composite hydrogel ( [email protected] Hydrogel) loaded with lactate and pyruvate, that exhibites a good free radical scavenging activity and an excellent ability to modulate the inflammatory response. Experimental results showe that this hydrogel film could effectively reduce the UV-induced skin inflammation response, alleviate pathological damage and promote the recovery of the damaged skin.

Biomimetic nanochannels for molybdate transport: application to sensitive electrochemical immunoassay for HER2

Du Chunyang,Jiao Jiao,Zhang Hongfang

A nanochannel-based electrochemical immunoassay was developed for the detection of human epidermal growth factor receptor 2 (HER2), with molybdate as the reporter to explore the interaction occurring into the nanochannels. The presence of target increased steric hindrance of the antibody-functionalized nanochannels, thereby hindering the transport of molybdate. And the reporter could be monitored by working electrode modified with hydroxyapatite nanoparticles, based on the formation of the redox-active molybdophosphate. As a result, peak current obtained at ca. − 0.28 V in square wave voltammograms could be applied to quantitative determination of HER2. The electrochemical signal increased linearly with the logarithm of the concentration of HER2 in a broad dynamic range of 0.1 pg∙mL −1 to 10 ng∙mL −1 with a detection limit of 0.05 pg∙mL −1 . The reliability of this immunoassay was validated by a recovery range of 99.5% to 111.7% for the detection of three different levels of HER2 in human serum samples. Integrating with multiple bionanochannels, this immunoassay is expected to provide a versatile approach for quantitative detection of various biomarkers in related disease diagnosis and therapy. Graphical Abstract

Comparative Study of Physicochemical Properties of Alginate Composite Hydrogels Prepared by the Physical Blending and Electrostatic Assembly Methods

Yanshi Wen,Xiuqiong Chen,Huiqiong Yan,Qiang Lin

Alginate hydrogel commonly suffers from defects, such as weak mechanical properties, the shortage of long-term stability in physiological medium and the lack of mammalian cell adhesivity due to its strong hydrophilicity in biomedical application. For this reason, the homogeneous alginate hydrogels (Alg Gel) were successfully prepared by the D-glucono-δ-lactone/hydroxyapatite (HAP/GDL) cross-linking system, and then, the physical blending and alternating electrostatic assembly technology were proposed to fabricate alginate composite hydrogels (Alg-GT, Alg-CS-GT and ALG/GT-CS). The feasibility of the design methods was verified through the comparative analysis of their physicochemical properties and biological activity. In particular, the effects of physical blending and alternating electrostatic assembly technology on the pore structure, mechanical properties, swelling, degradation, cell adhesion and proliferation of composite hydrogels were also investigated. Experimental results showed that the formation of polyelectrolyte complexes by electrostatic assembly between biological macromolecules and the covalent cross-linking of EDC/NHS to GT improved the vulnerability of ion cross-linking, enhanced the mechanical properties and swelling stability of the composite hydrogels, and regulated their pore structure and in vitro biodegradability properties. Furthermore, MC3T3-E1 cells could exhibit good cell adhesion, cell viability and cell proliferation on the alginate composite hydrogels. Among them, Alg-CS-GT showed the best cell proliferation ability and differentiation effect due to its good cell adhesion. In view of the excellent physicochemical properties and biological activity of Alg-CS-GT, it exhibited great potential in biomedical application for tissue engineering.Keywords:sodium alginate;physical blending;electrostatic assembly;composite hydrogels;tissue engineering