Dextran, also known as glucan, is a high molecular compound connected by glucosidic bonds. In 1869, Scheibler believed that it was similar to starch and dextrin, so he named it polyglucan, i.e. dextran. It is a high molecular glucan synthesized by fermentation of sucrose by certain bacteria (such as Leuconostocmesenteroides and Acetobactercapsulatum). The main chain is connected by α-D-(1→6) glycosidic bonds, and the side chain branch points are connected by α-D-(1→3) and α-D-(1→2). The relative molecular mass range is very wide, ranging from 5×104 to 3×108. Therefore, dextran and its derivatives are widely used in many fields such as medicine and food, and the market demand is large. Dextran is mainly synthesized by microbial fermentation of high molecular weight glucan, which is hydrolyzed into medium and low molecular weight dextran by acid, and then dextran products of different molecular weights are obtained by ethanol precipitation. The disadvantages of this method are that it not only consumes a lot of energy, but also has a wide molecular weight distribution range of the obtained product, and protein and chloride ion residues, which limit the clinical use of dextran. The main methods for preparing dextran are microbial fermentation and enzyme synthesis. Microbial fermentation is one of the main methods for producing dextran, that is, directly using intestinal leuconostoc to ferment high-concentration sucrose to synthesize dextran, and obtaining crude anhydride through ethanol precipitation, and then using hydrochloric acid to hydrolyze high molecular weight dextran into dextran of different molecular weights, and then obtain dextran products through a series of operations such as neutralization, decolorization and filtration. Dextran using enzyme engineering technology is currently a more advanced process technology that has received more research attention. Compared with the traditional fermentation method, this method has the advantages of continuous production, high efficiency and no pollution, strong specificity, easy control of product molecular weight, and low impurity content. The enzymatic synthesis of dextran is divided into two steps: 1. Preparation and purification of extracellular dextran sucrase; 2. Synthesis of dextran. With the rapid development and gradual maturity of bioengineering technology, molecular technology and immobilization technology provide theoretical and technical support for the enzymatic synthesis of dextran. Dextran can be used as a substitute for plasma or iron supplement because of its safety, non-toxicity and good biocompatibility. Clinical dextran with a relative molecular mass of 70000, 40000 and 20000u is currently effectively used for moderate blood loss. Dextran iron as a blood tonic is a commonly used anti-anemia drug. Since dextran contains a large number of active hydroxyl groups and is easy to modify, it is used in tissue engineering materials in the form of dextran-based hydrogel. As a new type of drug-controlled release carrier, it has attracted the attention and attention of many scholars because of its advantages of large drug loading, easy absorption, convenient administration and stable performance. The unique polymer advantages of dextran itself also provide a new basis for its use as a new type of medical dressing.
Figure 1. Design and application of dextran carrier. (Shiyu Huang, et al.; 2020)
AMCA (7-amino-4-methylcoumarin-3-acetic acid) is a widely used blue fluorescent dye. Due to its unique optical properties, AMCA is widely used in a variety of biomolecular labelling and detection technologies. The maximum excitation wavelength of AMCA is 345-350 nm and the maximum emission wavelength is 445-450 nm. When excited by excitation light, AMCA emits bright blue fluorescence and is therefore often used in experiments where clear and distinguishable fluorescence signals are required. Therefore, AMCA attached to the dextran nanoparticle carrier can be used to monitor drug delivery. AMCA is preferred for its high stability, which means that AMCA-labelled dextran can maintain a relatively stable fluorescence intensity in drug tracking experiments and is not prone to photobleaching.
Alternate Names:
AMCA-labeled dextran
AMCA-conjugated dextran
AMCA-dextran complex
Dextran-AMCA conjugate
AMCA-modified dextran
AMCA-dextran derivative
References:
1. Shiyu Huang, et al.; Design and application of dextran carrier. Journal of Drug Delivery Science and Technology. 2020, Volume 55, 101392.
2. Chen F, et al.; Preparation and application of dextran and its derivatives as carriers. Int J Biol Macromol. 2020, 145:827-834.
Application of dextran as nanoscale drug carriers
Nanomedicine (Lond).
Authors: Huang G, Huang H.
Abstract
Dextran is a kind of biocompatible, nontoxic and nonimmunogenic biological substance that has been widely used in drug-delivery systems. With further research and understanding of dextran and its derivatives, people can more precisely control the sequence of dextran by chemical and biosynthetic methods as needed, and modify various structures to improve the properties of dextran, such as hydrophilicity, hydrophobicity, temperature sensitivity, pH sensitivity and ionic strength sensitivity, which will further expand the application of dextran and its derivatives in drug-delivery systems. Herein, the application of dextran and its derivatives in gene transfection and drug delivery was summarized and analyzed, and the problems were studied. At the same time, its application prospects are forecasted.
Acetalated dextran based nano- and microparticles: synthesis, fabrication, and therapeutic applications
Chem Commun (Camb).
Authors: Wang S, Fontana F, Shahbazi MA, Santos HA.
Abstract
Acetalated dextran (Ac-DEX) is a pH-responsive dextran derivative polymer. Prepared by a simple acetalation reaction, Ac-DEX has tunable acid-triggered release profile. Despite its relatively short research history, Ac-DEX has shown great potential in various therapeutic applications. Furthermore, the recent functionalization of Ac-DEX makes versatile derivatives with additional properties. Herein, we summarize the cutting-edge development of Ac-DEX and related polymers. Specifically, we focus on the chemical synthesis, nano- and micro-particle fabrication techniques, the controlled-release mechanisms, and the rational design Ac-DEX-based of drug delivery systems in various biomedical applications. Finally, we briefly discuss the challenges and future perspectives in the field.
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