新工科背景下高等分离工程教学改革与实践

Facing the demand of strengthening the collaborative innovation ability of postgraduates under the background of emerging engineering education, the authors based on many years of teaching and scientific research experience carry out a series of teaching reforms on the teaching content, teaching methods, teaching means and assessment methods for the advanced separation engineering course. The project case base is established, case teaching and team cooperation are adopted to integrate multi-field professional knowledge and the latest scientific research achievements. Professional software is used to solve complex engineering problems, and the manual calculation and software calculation exercises are combined to strengthen the understanding and application of theoretical knowledge. The diversified assessment mode is taken to improve the study enthusiasm and autonomous learning ability. The practice shows that the teaching reforms and implementation of this course obviously improve the teaching effect, which is of great significance to the cultivation of postgraduates' comprehensive engineering ability, team communication and innovative thinking ability.     

羟烷基壳聚糖制备及应用研究进展

壳聚糖是由甲壳素通过脱乙酰作用得到的一种天然高分子多糖,具有良好的生物相容性、抗菌性、无毒和可生物降解等优点,但壳聚糖水溶性差限制了其在很多方面的应用。为克服壳聚糖在水溶性上的不足,利用壳聚糖结构中氨基和羟基上的活泼氢进行化学改性以引进羟烷基等亲水性基团成为重要手段。本文主要对壳聚糖羟烷基化改性的方法及羟烷基壳聚糖在医药、水处理和组织工程材料等领域的研究和应用现状进行介绍,并对羟烷基壳聚糖未来的发展趋势进行了展望。     

Biodegradable Polyesters for Tissue Engineering

Summary: Paper describes basic characteristics of synthesis and properties of aliphatic polyesters used for tissue engineering. Described is also synthesis of polyester containing block copolymers suitable for surface modification. Described are methods used for scaffold fabrication with required porosity. In particular, presented are methods according to which scaffolds are made from prefabricated polyester micro- and nanoparticles.     

Engineering Proteins at Interfaces: From Complementary Characterization to Material Surfaces with Designed Functions

Once materials come into contact with a biological fluid containing proteins, proteins are generally—whether desired or not—attracted by the material's surface and adsorb onto it. The aim of this Review is to give an overview of the most commonly used characterization methods employed to gain a better understanding of the adsorption processes on either planar or curved surfaces. We continue to illustrate the benefit of combining different methods to different surface geometries of the material. The thus obtained insight ideally paves the way for engineering functional materials that interact with proteins in a predetermined manner.     

组织工程用可生物降解聚合物多孔支架制备方法研究进展

可生物降解高分子多孔支架已广泛用作各种再生新组织模板,组织工程要求支架要有着良好的相互连通、高度开放的多孔结构,以实现细胞的增殖和分化。因此,如何把材料加工成满足生物体要求的结构至关重要。本文对最近几年组织工程用高孔隙率三维支架的制备方法进行了综述,并指出了各种方法的优缺点,展望了可降解高分子支架制备方法的发展前景。     

One‐Step Labeling of Collagen Hydrogels with Polydopamine and Manganese Porphyrin for Non‐Invasive Scaffold Tracking on Magnetic Resonance Imaging

Biomaterial scaffolds are the cornerstone to supporting 3D tissue growth. Optimized scaffold design is critical to successful regeneration, and this optimization requires accurate knowledge of the scaffold's interaction with living tissue in the dynamic in vivo milieu. Unfortunately, non‐invasive methods that can probe scaffolds in the intact living subject are largely underexplored, with imaging‐based assessment relying on either imaging cells seeded on the scaffold or imaging scaffolds that have been chemically altered. In this work, the authors develop a broadly applicable magnetic resonance imaging (MRI) method to image scaffolds directly. A positive‐contrast “bright” manganese porphyrin (MnP) agent for labeling scaffolds is used to achieve high sensitivity and specificity, and polydopamine, a biologically derived universal adhesive, is employed for adhering the MnP. The technique was optimized in vitro on a prototypic collagen gel, and in vivo assessment was performed in rats. The results demonstrate superior in vivo scaffold visualization and the potential for quantitative tracking of degradation over time. Designed with ease of synthesis in mind and general applicability for the continuing expansion of available biomaterials, the proposed method will allow tissue engineers to assess and fine‐tune the in vivo behavior of their scaffolds for optimal regeneration.     

Genetic engineering to enhance the selectivity of protein separations

The ability to recover and purify natural and recombinant proteins, and the costs of doing so remain a major task in introducing the potential products of biotechnology. The bases for separation range from specific binding onto tailored reagents to solubility and partitioning behavior governed by a mixed bag of size, charge, and hydrophobicity. In most cases, a combination of methods is used in sequence, and improvements in the selectivity at an early stage can enhance the effectiveness of subsequent (and usually more costly) steps. Genetic engineering provides a means of improving the selectivity within the context of existing separation methods. By this strategy, improvements in selectivity are sought by bestowing a distinctive property on the protein of interest. The primary sequence of amino acids is altered, such that the protein can be selectively removed from other components of the multicomponent mixture in which such products are commonly found. In this article, the range of these “distinctive properties” and their pairing with various separation methods will be reviewed. Specific examples from our work, in which a distinctive charge is provided via a polypeptide “purification” fusion tail, will be discussed. Separation methods we have used with these fusion proteins are precipitation, two-phase aqueous extraction, reversed micellar extraction, and ion exchange using both resins and membranes.     

Analysis of a Chemostat Model with Variable Yield Coefficient

We investigate a chemostat model in which the growth rate is given by a Monod expression with a variable yield coefficient. This model has been investigated by previous researchers using numerical integration. We combine analytical results with path-following methods. The conditions for washout to occur are found. When washout does not occur we establish the conditions under which the reactor performance is maximised at either a finite or infinite residence time. We also determine the parameter region in which oscillations may be generated in the reactor, which was the primary feature of interest to earlier workers on this problem.     

可降解聚氨酯型组织工程多孔支架材料的制备

本文在可降解型聚氨酯分子设计,聚氨酯型组织工程支架制备方法,可降解聚氨酯多孔支架的生物学性能及可降解聚氨酯多孔支架在组织工程中的应用等几个方面对可降解聚氨酯型组织工程支架的最新研究进展作了综述。重点讨论了静电纺丝、冷冻干燥、相分离等几种聚氨酯多孔支架制备方法以及聚氨酯型组织工程支架的生物降解性质、生长因子嵌入、生物力学性能、生物相容性等生物学性能。目前的研究表明通过聚氨酯分子设计与各种支架制备方法结合可制得满足各种生物学性能的支架材料且这类材料已被证实在血管、软骨、硬质骨等各类组织工程中有重要的应用价值。但如何进一步提高聚氨酯支架材料的力学强度以使其能更好地与硬组织的力学性能相匹配以及如何降低或消除聚氨酯对人体的毒性仍是需要进一步研究的问题。     

Sortagging: A Robust and Efficient Chemoenzymatic Ligation Strategy

Bioorthogonal, chemoselective ligation methods are an essential part of the tools utilized to investigate biochemical pathways. Specifically enzymatic approaches are valuable methods in this context due to the inherent specificity of the deployed enzymes and the mild conditions of the modification reactions. One of the most common strategies is based on the transpeptidation catalyzed by sortase A derived from Staphylococcus aureus. The procedure is well established and a wide variety of applications have been published to date. Here, implementations of sortase A, which range from protein labeling using fluorescence dyes and the preparation of cyclic proteins to the modification of entire cells, are summarized. Furthermore, there is a focus on the optimization approaches established to solve the drawbacks of sortase‐mediated transpeptidation.     

Advancements in biocatalysis: From computational to metabolic engineering

Through several waves of technological research and un-matched innovation strategies, bio-catalysis has been widely used at the industrial level. Because of the value of enzymes, methods for producing value-added compounds and industrially-relevant fine chemicals through biological methods have been developed. A broad spectrum of numerous biochemical pathways is catalyzed by enzymes, including enzymes that have not been identified. However, low catalytic efficacy, low stability, inhibition by non-cognate substrates, and intolerance to the harsh reaction conditions required for some chemical processes are considered as major limitations in applied bio-catalysis. Thus, the development of green catalysts with multi-catalytic features along with higher efficacy and induced stability are important for bio-catalysis. Implementation of computational science with metabolic engineering, synthetic biology, and machine learning routes offers novel alternatives for engineering novel catalysts. Here, we describe the role of synthetic biology and metabolic engineering in catalysis. Machine learning algorithms for catalysis and the choice of an algorithm for predicting protein-ligand interactions are discussed. The importance of molecular docking in predicting binding and catalytic functions is reviewed. Finally, we describe future challenges and perspectives.     

Synthesis of BiOClxBr1−x Nanoplate Solid Solutions as a Robust Photocatalyst with Tunable Band Structure

The use of bismuth oxyhalides as photocatalysts has received extensive interest because of their high photocatalytic activity and stability. However, available methods for the synthesis of bismuth oxyhalides with tailored morphologies, well‐defined facets, and tunable band gaps are still lacking. In this work, two‐dimensional BiOCl_xBr_1?x solid solution with exposed {001} facets and tunable band gaps were synthesized by using solvothermal methods. The BiOCl_xBr_1?x solid solution nanoplates crystallized in a homogeneous crystal structure but possessed continuously tuned band gaps from 3.39 to 2.78 eV by decreasing the ratio of Cl/Br. Among the synthesized nanoplates, the BiOCl_0.5Br_0.5 sample exhibited the highest photocatalytic activity for degrading Rhodamine B (RhB), a typical organic pollutant, under visible light. The highest photoactivity of the BiOCl_0.5Br_0.5 sample was attributed to a synergetic effect of higher surface area, facets exposed, and optimized band structure. The results are of profound significance for the design of novel photocatalyst materials.     

Engineering and assaying of cytochrome P450 biocatalysts

Cytochrome P450s constitute a highly fascinating superfamily of enzymes which catalyze a broad range of reactions. They are essential for drug metabolism and promise industrial applications in biotechnology and biosensing. The constant search for cytochrome P450 enzymes with enhanced catalytic performances has generated a large body of research. This review will concentrate on two key aspects related to the identification and improvement of cytochrome P450 biocatalysts, namely the engineering and assaying of these enzymes. To this end, recent advances in cytochrome P450 development are reported and commonly used screening methods are surveyed.     

Myoglobin‐Catalyzed Olefination of Aldehydes

The olefination of aldehydes constitutes a most valuable and widely adopted strategy for constructing carbon–carbon double bonds in organic chemistry. While various synthetic methods have been made available for this purpose, no biocatalysts are known to mediate this transformation. Reported herein is that engineered myoglobin variants can catalyze the olefination of aldehydes in the presence of α‐diazoesters with high catalytic efficiency (up to 4,900 turnovers) and excellent E diastereoselectivity (92–99.9 % de). This transformation could be applied to the olefination of a variety of substituted benzaldehydes and heteroaromatic aldehydes, also in combination with different alkyl α‐diazoacetate reagents. This work provides a first example of biocatalytic aldehyde olefination and extends the spectrum of synthetically valuable chemical transformations accessible using metalloprotein‐based catalysts.     

生物工程专业化工原理理论教学的改革与探索

在当前高等学校注重创新创业人才培养的教育改革背景下,从生物工程专业化工原理理论教学如何从教学内容的载体、教学方法、考核方式等方面改革出发,探讨了适合工科院校化工原理教学加强实践和创新能力,培养创新型人才的新途径。     

闯关式与翻转式结合的课堂教学方法——以化工原理课程为例

Flipped classroom and open classroom are both new teaching modes to improve the efficiency of teaching. Based on the combination of these two teaching strategies and the principles of chemical engineering course, this article uses the distillation section as an example to illustrate the implement process of this teaching mode. In light of the characteristics of the principles of chemical engineering course, we design and introduce the combination of the flipped and open classroom into teaching, and results of this strategy, mainly including teaching analysis, teaching strategy, teaching process and effectiveness. We come up with teaching methods and modes that are well suited to the learning characteristics of undergraduates, aiming to provide references.     

Reactions between or within molecular crystals

Reactions that occur within or between molecular crystals, in particular those reactions that are activated by mechanical methods, are reviewed. The focus is on processes (whether intrasolid or intersolid) that are controlled primarily by supramolecular bonding, such as template cycloadditions, formation of inclusion compounds, reactions between molecular crystals by the reassembling of noncovalent bonds, and the formation of complexes and coordination compounds. It is proposed that solvent-free mechanochemical methods, for example, cogrinding, milling, and kneading, represent viable "green" routes for the preparation of novel molecular and supramolecular solids.     

Harnessing the full potential of extracellular vesicles as drug carriers

Extracellular vesicles are natural delivery systems widely implicated in cellular communication. However, to fully utilize these vehicles as nanocarriers, we must explore various methods to modify their applicability as drug delivery vehicles. In this review, we outline and discuss techniques to engineer extracellular vehicles for enhanced loading, targeting, circulation, and tracking. We highlight cutting-edge methods to amplify extracellular vesicle secretion and production and optimize storage conditions to improve their clinical suitability. Moreover, we focus on reverse engineering as an important step in controlling their biological function. By taking a reductionist approach to characterize and understand the individual components of these carriers, we can not only elucidate complex mechanisms of action but also advance the field through the creation of synthetic drug delivery vehicles. Finally, we propose current challenges and future directions of the field.     

Metabolic Engineering of Microbial Cell Factories for Biosynthesis of Flavonoids: A Review

Flavonoids belong to a class of plant secondary metabolites that have a polyphenol structure. Flavonoids show extensive biological activity, such as antioxidative, anti-inflammatory, anti-mutagenic, anti-cancer, and antibacterial properties, so they are widely used in the food, pharmaceutical, and nutraceutical industries. However, traditional sources of flavonoids are no longer sufficient to meet current demands. In recent years, with the clarification of the biosynthetic pathway of flavonoids and the development of synthetic biology, it has become possible to use synthetic metabolic engineering methods with microorganisms as hosts to produce flavonoids. This article mainly reviews the biosynthetic pathways of flavonoids and the development of microbial expression systems for the production of flavonoids in order to provide a useful reference for further research on synthetic metabolic engineering of flavonoids. Meanwhile, the application of co-culture systems in the biosynthesis of flavonoids is emphasized in this review.     

Eco-Friendly Nitrogen-Doped Graphene Preparation and Design for the Oxygen Reduction Reaction

Four N-doped graphene materials with a nitrogen content ranging from 8.34 to 13.1 wt.% are prepared by the ball milling method. This method represents an eco-friendly mechanochemical process that can be easily adapted for industrial-scale productivity and allows both the exfoliation of graphite and the synthesis of large quantities of functionalized graphene. These materials are characterized by transmission and scanning electron microscopy, thermogravimetry measurements, X-ray powder diffraction, X-ray photoelectron and Raman spectroscopy, and then, are tested towards the oxygen reduction reaction by cyclic voltammetry and rotating disk electrode methods. Their responses towards ORR are analysed in correlation with their properties and use for the best ORR catalyst identification. However, even though the mechanochemical procedure and the characterization techniques are clean and green methods (i.e., water is the only solvent used for these syntheses and investigations), they are time consuming and, generally, a low number of materials can be prepared, characterized and tested. In order to eliminate some of these limitations, the use of regression learner and reverse engineering methods are proposed for facilitating the optimization of the synthesis conditions and the materials’ design. Thus, the machine learning algorithms are applied to data containing the synthesis parameters, the results obtained from different characterization techniques and the materials response towards ORR to quickly provide predictions that allow the best synthesis conditions or the best electrocatalysts’ identification.