CM-dextrans are manufactured by reacting selected dextran fractions with an activated carboxymethyl derivative in alkali. This leads to the introduction of O-carboxymethyl groups along the dextran chain. The carboxyl content is approximately 5% which is equivalent to about one CM group for every 5 five glucose units. Higher degrees of substitution may be achieved if required. The dextran used is elaborated by Leuconostoc mesenteroides B512F ａnd is essentially a linear α (1-6)-linked glucose chain with a low percentage(2-5%) of α(1-3) branches distributed along the chain. The dextran fractions used have weight average molecular weights (Mw) of 4000 to 2000000 ａnd are carefully controlled by GPC, optical rotation, absorbance ａnd loss on drying.

Physical properties

Carboxymethyl dextran (CM-dextran) is a white, odourless ａnd tasteless powder which is freely soluble in water or electrolyte solutions. The product has a pronounced polyanionic character by virtue of the negatively charged carboxyl groups attached. The solution properties of CM-dextran are described in several publications (1,2). In neutral solutions, the carboxymethyl substituents will repel

each other leading to an expansion of the dextran coil (2). This effect is observed when the products are examined by gel permeation chromatography (GPC) whereby the apparent weight average molecular weight (Mw) is approximately 10% higher than that of the starting dextran. CM-dextrans are insoluble in most organic solvents, for example, ethanol, methanol, acetone, chloroform, ethyl acetate Etc

Applications

Important spheres of research where CM-dextrans are employed are listed below.

1. Carriers of paramagnetic contrast agents. (3-4)

2. Preparation of conjugates of pharmacologically active compounds (5-7)

3. CM-dextrans in biosensors (8-14)

4. CM-dextrans for preparing iron containing nanoparticles (4,15)

5. Many early patents describe uses for CM-dextrans in cosmetic, agricultural, food, paints,

textiles applications

CM-dextran（CM--葡聚糖，羧甲基--dextran，Carboxymethyl-dextran）：

艾美捷CM-dextran#CMD4、CMD10、CMD20等為白色、無(wú)臭無(wú)味粉末，易溶于水和電解質(zhì)溶液。羧甲基含量對(duì)應(yīng)于每5個(gè)葡萄糖單元約1個(gè)CM基團(tuán)，羧基含量為3 - 7%。

CM-dextran#CMD4、CMD10、CMD20等潛在的應(yīng)用域包括：

通過(guò)羧基反應(yīng)結(jié)合陽(yáng)離子（無(wú)機(jī)和有機(jī)）的試劑

化妝品

制劑中的無(wú)毒成分

用于敏感生物聚合物的穩(wěn)定劑

CM-dextran的物理性質(zhì)：

羧甲基-葡聚糖（CM-dextran）是一種白色、無(wú)臭、無(wú)味的粉末，可自由釋放可溶于水或電解質(zhì)溶液。該產(chǎn)品具有明顯的聚陰離子特征由于所連接的帶負(fù)電荷的羧基。在中性溶液中，羧甲基取代基會(huì)排斥相互作用導(dǎo)致-dextran線圈（2）的膨脹。當(dāng)產(chǎn)品通過(guò)凝膠滲透色譜法（GPC）檢查，由此表觀重量平均值分子量（Mw）比起始-dextran的分子量高約10%。CM-dextran是不溶于大多數(shù)有機(jī)溶劑，例如乙醇、甲醇、丙酮、氯丨仿、乙酸乙酯等

CM-dextran的化學(xué)性質(zhì)：

在dextran鏈中插入羧基提供了進(jìn)一步的固定化機(jī)會(huì)具有有趣生物活性的分子（藥物、酶、診斷示蹤劑）-dextran。羧基部分可用于許多反應(yīng)，例如酯化、酰胺化與胺、Ugi或Passerini反應(yīng)。簡(jiǎn)單的離子結(jié)合反應(yīng)也可以提供一系列包含不同陽(yáng)離子分子的衍生物。

文獻(xiàn)參考：

1. K.Gekko, Solution properties of dextran ａnd its ionic derivatives, ACS Symposium Series, 1981, 150, 415-438;K.Gekko ａnd H.Noguchi, Selective interaction of calcium ａnd , magnesium ions with ionic dextran derivatives, Carbohydr. Res., 1979, 69, 323-326.

2. O.Smidsröd, Estimation of the relative stiffness of the molecular chain in polyelectrolytes from viscosity measurements at different ionic strengths. Comparison of polycations ａnd polyanions, Acta Chem.Scand., 1971, 25(7) 2770-1.

3. P.Rongved ａnd J.Klaveness, Water soluble polysaccharides as carriers of paramagnetic contrast reagents for magnetic resonance imaging; Synthesis ａnd relaxation properties, Carbohyd.Res., (1991), 214, 315-323.

4. S.W.Zheng, M.Huang et al., RGD-conjugated iron oxide magnetic nanoparticles for magnetic resonance imaging contrast enhancement ａnd hyperthermia, J.Biomater.Appl., 2014, 28 1051-1059.

5. M.Baudys, D.Letourneur et al., Extending insulin action in vivo by conjugation to carboxymethyl dextran, Bioconj. Chem., 1998, 9,176-183. Y.Ota, P.Oehr et.al., The application of immunotargetting into cancer therapy with carboplatin; in vitro ａnd in vivo studies, Asia Oceania J.Obstet.Gynaecol., 1993, 19(4), 449-457.

6. H.Ma, X.Li et. Ala., High antimetastatic efficacy of MEN4901/T-0128, a novel campothecin carboxymethyldextran conjugate, J.Surg.Res., 2011, 171(2), 684-690.

7. C.Situ, A.R.G.Wylie, A.Douglas et al., Reduction of severe bovine serum associated matrix effects on carboxymethylated dextran coated biosensor surfaces, Talanta, 2008, 76, 832-836.

8. S.Howell, M.Kenmore, M.Kirkland et al., High-density immobilization of an antibody fragment to a carboxymethylated dextran –linked biosensor surface, J.Mol.Recognit., 1998, 11, 200-3.

9. J.S.Mitchell ａnd Y.Wu, Surface Plasmon Resonance Biosensors for highly sensitive detection of small biomolecules, Biosensors, ISBN, 978-953-7619-99-2.

10. J-F.Masson, T.M.Battaglia, J.Cramer et al., Reduction of non-specific protein binding on surface plasmin resonance biosensors, Anal. Bioanal.Chem., 2006, 386, 1951-1959.

11. A.J.T.George, Measurement of the kinetics of biomolecular interactions using IAsys resonant mirror biosensor, Current protocols in Immunology, Unit number: Unit 18.5, DOI: 10.1002/0471142735.im1805s33; Posting date ; May 2001.

12. W.Jia, X-S.Liu, Y.Zhu et al., Preparation ａnd characterisation of Mabs against different epies of CD226, Hybridoma, 2000, 19, 489-494. S.Löfås, Dextran modified self-assembled monolayer surfaces for use in biointeraction analysis with surface Plasmon resonance, Pure ａnd Appl. Chem., 1995, 67, 829-834.

13. V.Ayala, A.P.Herrera et. al., Effect of surface charge on the colloidal stability ａnd in vitro uptake of carboxymethyl dextran coated iron oxide nanoparticles, J.Nanopart.Res., 2013, 15(8), 1874

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