CN114518453B - 一种多壁碳纳米管复合物及其制备方法和应用 - Google Patents

一种多壁碳纳米管复合物及其制备方法和应用 Download PDF

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CN114518453B
CN114518453B CN202210091643.6A CN202210091643A CN114518453B CN 114518453 B CN114518453 B CN 114518453B CN 202210091643 A CN202210091643 A CN 202210091643A CN 114518453 B CN114518453 B CN 114518453B
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escherichia coli
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庞立冬
姜毓君
满朝新
杨鑫焱
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Northeast Agricultural University
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Abstract

本发明公开了一种多壁碳纳米管复合物及其制备方法和应用,所述多壁碳纳米管复合物主要是由多壁碳纳米管和羰基铁粉制成。本发明还公开了一种由所述多壁碳纳米管复合物制成荧光型适体传感器及其制备方法。与现有技术相比,本发明采用一步法合成多壁碳纳米管复合物,方法简单,安全,有效,所得多壁碳纳米管复合物具备磁性,可以框荧光标记的核酸适体进行吸附,制备荧光型适体传感器,可以用于快速检测大肠杆菌,尤其是用于大肠杆菌O157:H7的快速检测。

Description

一种多壁碳纳米管复合物及其制备方法和应用
技术领域
本发明属于大肠杆菌检测技术领域,尤其涉及一种多壁碳纳米管复合物及其制备方法和应用。
背景技术
多壁碳纳米管因特殊结构、表面官能团修饰和π键堆积的作用,可以在共价或非共价作用下,连接具有不同靶向功能的核酸适体等生物分子。Gu等人利用聚乙二醇作为粘接剂,将羟基化多壁碳纳米管与修饰氨基的核酸适体进行共价连接,用于诊断***癌疾病,在细胞和动物试验中均进行了验证。Barbosa等人采用超声作为主要处理手段,将多壁碳纳米管和核酸适体进行非共价连接,用于检测人的结肠癌细胞,在细胞毒性试验中得到了良好的结果。虽然单一的多壁碳纳米管具有较好的连接特性,但也满足不了日渐增多的需求,若将多壁碳纳米管赋予磁性,既能简化材料的分离过程,又能增强纳米材料的应用性。溶剂热法和化学共沉淀法是最为常用的两种方法,可以将铁离子还原在多壁碳纳米管表面上,得到附着有磁性颗粒的多壁碳纳米管,在较多领域进行应用。Deng等人采用溶剂热法在多壁碳纳米管表面上附着Fe3O4,并验证了复合材料具有很好的催化酸性橙Ⅱ的活性。刘苛等人采用化学共沉淀法制备了磁性多壁碳纳米管,并探究了去除水中亚甲基蓝和铜的作用。由此可见,多壁碳纳米管在赋予磁性后,增加了更多的应用功能,但这两种传统制备磁性多壁碳纳米管的方法比较费时费力,并往往需要采取高温的条件或者有刺激性和腐蚀性的试剂等,在试验的过程中应该做好相应防护措施,否则误操作便可能造成人身损伤。这显然不适应绿色化学的发展趋势,且对于非专业工作者产生一定的限制,因此,一种简单、安全、便捷且适应性强的有效复合方法是有非常重要意义的。
发明内容
发明目的:为了解决现有技术中存在的问题,本发明提供了一种多壁碳纳米管复合物及其制备方法和应用,该多壁碳纳米管复合物可以用于制成荧光型适体传感器,能够快速检测大肠杆菌。
技术方案:为了达到上述发明目的,本发明采用如下技术方案:
一种多壁碳纳米管复合物,其主要是由多壁碳纳米管和羰基铁粉制成。
优选的,所述多壁碳纳米管和羰基铁粉的比例为1:(1-6),更优选1:3。
优选的,所述多壁碳纳米管选自羧基化多壁碳纳米管。
所述的多壁碳纳米管复合物的制备方法,包括以下步骤:
(1)将多壁碳纳米管加入到缓冲液中,混匀,然后加入EDC和NHS,反应;
(2)步骤(1)反应结束后,加入羰基铁粉,混匀后,继续反应,即得。
优选的,步骤(1)中,所述缓冲液为pH 4.0-6.0的缓冲液MES,更优选pH 5.0。
优选的,步骤(1)中,所述反应的时间为110-130min;所述反应在25±2℃、160-200rpm的摇动中反应。
优选的,步骤(2)中,所述反应的时间为20-70min,更优选60min;所述反应在25±2℃、160-200rpm的摇动中反应。
所述的多壁碳纳米管复合物在快速检测大肠杆菌中的应用,尤其是在快速检测大肠杆菌O157:H7中的应用。
一种荧光型适体传感器,由所述的多壁碳纳米管复合物制成。
所述荧光型适体传感器的制备方法,包括以下步骤:
(1)取所述多壁碳纳米管复合物,加入去离子水,分散,然后与大肠杆菌适体混合;
(2)取上述混合物,超声分散50-70min后,4±2℃静置;
(3)磁选分离后,用去离子水洗涤3-5次,收集重悬后的溶液,即得。
优选的,所述大肠杆菌适体选自大肠杆菌O157:H7适体,其5’端修饰6-FAM基团,其核苷酸序列如SEQ ID NO.1所示:6-FAM-CGGACGCTTATGCCTTGCCATCTACAGAGCAGGTGTGACGG;所述多壁碳纳米管复合物与大肠杆菌适体的比例为1:1。
本发明多壁碳纳米管复合材料的制备采用一步法完成,复合材料的形成过程主要包含羧基化多壁碳纳米管的水解反应,羰基铁粉的置换反应,羰基铁粉和多壁碳纳米管的化合反应以及羰基铁粉的氧化反应。使用EDC和NHS以激活和稳定多壁碳纳米管表面的羧基,同时起到交联剂作用。随着羰基铁粉的加入,羰基铁会与溶液中的H+发生置换反应,生成带有正电荷的Fe2+,并依附在羰基铁粒子的表面,在相反电荷的静电吸引作用下,带有负电荷的羧基化多壁碳纳米管会与带正电荷的羰基铁粒子结合,两者紧密吸附,形成碳纳米管复合物。本发明制备多壁碳纳米管复合物发生的化学反应过程和示例如图1所示。
本发明多壁碳纳米管复合物的光学性质被应用于荧光型适体传感器的检测过程中,检测原理如图2所示。向多壁碳纳米管复合物分散均匀的溶液中,加入标记荧光基团的大肠杆菌O157:H7核酸适体,在多壁碳纳米管复合物表面π键作用下,将适体非共价吸附在复合物的表面,两者的吸附会发生荧光共振能量转移,使得适体标记的荧光基团出现猝灭的效果,由此得到了新型荧光适体传感器。当待测样存在目标菌时,标记荧光基团的适体会从多壁碳纳米管复合物表面脱离,去结合目标菌,将复合物在外磁场作用下分离后,溶液中的荧光基团会恢复荧光信号。反之,若待测样中没有目标菌,在非共价吸附作用下,核酸适体还是会附着在多壁碳纳米管复合物的表面,此时荧光基团的信号仍然保持淬灭,并在外磁场作用下,随着多壁碳纳米管复合物分离出溶液,因此不会在溶液中检测到荧光信号。从而实现依据磁分离后溶液荧光信号的强度,指示待测样中不同浓度的大肠杆菌O157:H7。
本发明主要利用氧化还原反应,一步法合成了多壁碳纳米管和羰基铁粉的复合物,由于多壁碳纳米管自身的吸附作用容易发生团聚,通常在溶剂中出现无法分散的情况,所以单纯利用多壁碳纳米管的自然性质完成在溶剂中均匀分散很不容易实现。本发明向羧基化多壁碳纳米管的酸性MES缓冲溶液中加入了EDC和NHS,可以起到激活多壁碳纳米管表面羧基以及提升纳米材料稳定性的作用,进而增强多壁碳纳米管在水溶液中的分散性。另外,EDC和NHS的联合使用还充当一定的交联剂作用,酸性MES缓冲液不仅促进了交联剂作用的发挥,还为铁粒子的置换反应提供了适宜的条件。本研究摆脱了传统制备磁性复合碳纳米材料的手段,得到了一种简单、安全和有效的复合方法,采用的多壁碳纳米管直径很小(小于8nm),更加证实此复合方法可以将磁性粒子有效的结合在多壁碳纳米管的表面。因此,本发明为合成磁性碳复合纳米材料方向提供了可能,并且可以将此复合方法推广到较大直径的多壁碳纳米管或者其他种类的纳米材料上,充分发挥多种复合纳米材料的独特应用性。
本发明采用的多壁碳纳米管具有较大的比表面积,复合羰基铁粉后,使其具备了磁性。在多壁碳纳米管表面非共价吸附的作用下,可以将荧光标记的核酸适体进行吸附,在荧光共振能量转移下,使荧光基团产生了猝灭,在不同浓度靶标物存在时,荧光信号会得到不同程度的恢复,以此得到基于多壁碳纳米管复合物构建的荧光型适体传感器,并在实际牛乳样品中进行了应用。
有益效果:与现有技术相比,本发明采用一步法合成多壁碳纳米管复合物,方法简单,安全,有效,所得多壁碳纳米管复合物具备磁性,可以框荧光标记的核酸适体进行吸附,制备荧光型适体传感器,可以用于快速检测大肠杆菌,尤其是用于大肠杆菌O157:H7的快速检测。
附图说明
图1为本发明制备多壁碳纳米管复合物发生的化学反应过程和原理示意图。
图2为本发明多壁碳纳米管复合物应用于荧光型适体传感器的检测原理示意图。
图3为本发明多壁碳纳米管复合物的zeta电位分析结果。
图4为本发明多壁碳纳米管复合物的傅里叶变换红外光谱分析结果。
图5为本发明多壁碳纳米管复合物的透射电子显微镜与能谱分析结果,其中:a)多壁碳纳米管透射电镜图;b&c)多壁碳纳米管复合物透射电镜图;d)多壁碳纳米管复合物能谱分析结果。
图6为本发明荧光适体传感器的特异性结果。
图7为本发明荧光型适体传感器的灵敏性结果,其中:a)大肠杆菌O157:H7纯培养下的灵敏性;b)大肠杆菌O157:H7污染牛乳样品的灵敏性。
图8为本发明荧光型适体传感器的重现性结果。
具体实施方式
下面结合具体实施例,进一步阐明本发明,应理解这些实施例仅用于说明本发明而不用于限制本发明的范围,在阅读了本发明之后,本领域技术人员对本发明的各种等价形式的修改均落于本申请所附权利要求所限定。
表1以下实施例所用菌株信息
Figure BDA0003489442630000041
Figure BDA0003489442630000051
表2以下实施例所用试剂
Figure BDA0003489442630000052
表3以下实施例所用主要仪器
Figure BDA0003489442630000053
Figure BDA0003489442630000061
大肠杆菌O157:H7适体的核苷酸序列如SEQ ID NO.1所示:6-FAM-CGGACGCTTATGCCTTGCCATCTACAGA GCAGGTGTGACGG。
实施例1多壁碳纳米管复合物的制备
(1)称取适量的羧基化多壁碳纳米管加入到装有0.1mol/L的MES(pH 4.0)玻璃瓶中,将多壁碳纳米管制备成1mg/mL的浓度,摇晃混匀。
(2)加入40mmol/L的EDC和NHS各200μL,混匀后,置于25℃、180rpm的摇床中,反应120min。
(3)以多壁碳纳米管和羰基铁粉为1:3的比例,加入羰基铁粉,混匀后,25℃、180rpm的摇床中,反应60min,即得。
实施例2多壁碳纳米管复合物的表征
1、zeta电位分析
利用马尔文粒径分析仪分别对多壁碳纳米管、羰基铁粉、多壁碳纳米管和羰基铁粉复合物的表面电荷进行分析。详细的测定步骤如下:将马尔文粒径分析仪的专用zeta电位测定比色皿清洗3次;在测试的软件中选择测定zeta电位的功能;将样品加入到比色皿的规定刻度以内,按照正确方向,摆放到对应的放置;样本是黑色溶液,因此调整参数为吸收率进行测定;重复3次测定,记录数据并作图分析。
zeta电位通常是用来实现对纳米颗粒表面电荷表征的方法。分析结果如图3所示,多壁碳纳米管的材料表面呈现出带有21.7mv的负电荷,羰基铁粉的材料表面呈现出带有3.4mv的正电荷,多壁碳纳米管和羰基铁粉复合物表面呈现出1.4mv的负电荷,处于两种原材料的中间。这表明,在最优的复合反应条件下,两种纳米材料表面电性相反的电荷发生活化或增多后,随着氧化还原反应的进行,形成复合物的表面电荷量逐渐减少,并趋近于无电荷的状态。电性相同电荷量的减少,也会使纳米颗粒之间的静电斥力减弱,这可能会促进纳米颗粒产生一定程度的聚集,聚集后单个纳米材料的表面积增大,会更有利于后续进行复合物表面核酸小分子连接和磁性分离的过程。
2、傅里叶变换红外光谱分析
利用傅里叶变换红外光谱仪分别对多壁碳纳米管、羰基铁粉、多壁碳纳米管和羰基铁粉复合物的表面官能团进行分析。详细的测定步骤如下所示:用研钵将纳米材料研磨成极细小的粉末状;压成圆形的光滑薄片;上机进行测试。依据出峰位置进行官能团分析,记录数据并重新作图分析。
傅里叶变换红外光谱通常是用来实现对纳米颗粒表面官能团表征的方法。分析结果如图4所示,羰基铁粉的表面没有呈现明显的官能团,仅有较弱的CO2峰,因此纳米材料的表面羰基含量是极低的,利用羰基进行复合反应是不可行的。而多壁碳纳米管的表面呈现两处较为明显的官能团吸收峰,分别是在3425cm-1和1682cm-1的羟基和羰基,这是由于原材料表面具有较多的羧基所引起的,大量的羧基化纳米颗粒对于复合反应的发生,具有一定的促进作用。对于多壁碳纳米管和羰基铁粉的复合物而言,3425cm-1的羟基峰强度明显减弱,1682cm-1的羰基峰还存在复合物中,这是由于在氧化还原反应中,羧基的氢离子发生电离,铁离子取代氢离子的位置,因而破坏了复合物表面的羟基。复合物非常微弱的羟基峰强度,反映出纳米材料的表面羧基位点,几乎完全被占据,羟基已被大量破坏。最为重要的是,复合物在610cm-1处出现了一个非常强的新峰,这是铁离子和羧基反应后所产生的,是铁离子结合到羧基化多壁碳纳米管的标志性吸收峰。新峰的出现,说明铁离子已经和羧基发生了氧化还原反应,已经生成了多壁碳纳米管和羰基铁粉的复合物。
3、透射电子显微镜与能谱分析
利用透射电子显微镜和扫描电子显微镜分别对多壁碳纳米管、羰基铁粉、多壁碳纳米管和羰基铁粉复合物的表面形貌和元素含量分布进行分析。详细的测定步骤如下所示:将纳米材料分散在溶液中;超声30min;静置,使纳米材料产生沉降;取分散性好的上方液体滴加到载网膜;烘干后放入透射电子显微镜中观察表面形貌,用扫描电子显微镜对特定区域进行能谱分析,拍摄结果并比较分析。
透射电子显微镜通常是被用来观察纳米材料表面形貌最直观的表征方法之一。能谱分析通常是被用来测定纳米颗粒中含有元素类型的表征方法。分析结果如图5所示,在观察500nm的透射电镜下(图5(A)和(B)),复合反应前后多壁碳纳米管的形态和直径得到了较好的保留,原始多壁碳纳米管的长度较长,并且呈现出明显的弯曲和重叠,不利于充分发挥表面的吸附作用。而进行氧化还原反应后的复合材料长度较短,仅有轻微的弯曲和较少的重叠,可以较为充分的利用复合材料的表面积。在观察50nm的透射电镜下(图5(C)),可以清楚的看到有羰基铁粉连接在多壁碳纳米管的表面上,这会给复合材料赋予磁性。进一步对复合材料的元素种类做出定性分析(图5(D)),复合反应后的纳米材料同时具有C和Fe元素,表明复合材料是多壁碳纳米管和羰基铁粉的结合物。因此,本研究采用的氧化还原复合法可以将具有磁性的羰基铁粉结合到直径极小(小于8nm)的多壁碳纳米管表面,也可以将其推广至其他较大直径范围的多壁碳纳米管材料上
实施例3荧光型适体传感器的构建
(1)称取适量实施例1制备好的多壁碳纳米管复合物,加入装有去离子水的2mL离心管中,制备成浓度为1mg/mL,超声分散60min。
(2)取超声后的多壁碳纳米管复合物溶液和浓度为100nmol/L的大肠杆菌O157:H7适体混合,两者比例为1:1。
(3)将上述混合物超声分散60min后放入4℃冰箱过夜。
(4)磁选分离后,用去离子水洗涤,收集重悬后的溶液,即得。
实施例4荧光型适体传感器的性能验证和应用
1、荧光型适体传感器的特异性验证
选取实验室购买或分离保藏的食源性致病菌菌株(见表1),进行荧光型适体传感器的特异性验证。先采用无菌去离子水将所有试验菌株的纯培养调整为同一浓度,然后,将菌株纯培养物和荧光适体传感体系,以10:1的体积比例,在避光的棕色离心管中充分混合,阴性对照组采用无菌去离子水替代细菌,其余操作与阳性试验组相同,涡旋振荡后,放在37℃培养箱中孵育10min。最后,在磁铁架上分离多壁碳纳米管复合物后,移取溶液到黑色的96孔板,在酶标仪492nm的激发波长和532nm发射波长的条件下,进行各样品的荧光测量,做三次平行试验。记录各菌株的样品荧光强度,比较分析荧光型适体传感器的特异性。
在荧光型适体传感器的特异性验证中,对于4株大肠杆菌O157:H7菌株的检测,荧光强度恢复值较大,而对空白对照和23株非大肠杆菌O157:H7菌株的检测,没有较为明显荧光强度的恢复,通过与空白对照的结果比较,判定比色型适体传感器对于大肠杆菌O157:H7具有较好的特异性,结果如图6所示。
2、荧光型适体传感器的灵敏性检验
将大肠杆菌O157:H7作为荧光型适体传感器灵敏性检验的研究对象,分别探究了目标菌在纯培养和污染实际牛乳样品下的灵敏性。在大肠杆菌O157:H7纯培养检测中,采用无菌去离子水对目标菌进行洗涤和10倍的梯度稀释,稀释涂布平板法判定不同菌液的浓度。然后,分别将各浓度梯度的菌液和荧光适体传感体系,以10:1的体积比例,在避光的棕色离心管中充分混合,阴性对照组采用无菌去离子水替代细菌,其余操作与阳性试验组相同,涡旋振荡后,放在37℃培养箱中孵育10min。最后,在磁铁架上分离多壁碳纳米管复合物,移取溶液到黑色的96孔板,在酶标仪492nm的激发波长和532nm发射波长的条件下,进行各样品的荧光测量,做三次平行试验。记录各浓度梯度目标菌的样品荧光强度,分析荧光型适体传感器检测大肠杆菌O157:H7纯培养的灵敏度。
在大肠杆菌O157:H7污染实际牛乳样品的检测中,试验采用的市售超高温灭菌牛乳都经过国标GB 4789.36-2016的检测,无目标菌的存在。用无菌去离子水对大肠杆菌O157:H7进行洗涤和梯度稀释,采用稀释涂布平板法判定不同菌液的浓度。再将各梯度浓度的菌液分别污染液体牛乳,阴性对照组采用无菌去离子水替代细菌,其余操作与阳性试验组相同,都放置在37℃、180rpm的摇床中孵育1h。将孵育后的样品采用国际GB 4789.18-2010的方法对液体牛乳样品进行处理,将处理过的样品和荧光适体传感体系,以10:1的体积比例,在避光的棕色离心管中充分混合,涡旋振荡后,置于在37℃培养箱中孵育10min。最后,在磁铁架上分离多壁碳纳米管复合物,移取溶液到黑色的96孔板,在酶标仪492nm的激发波长和532nm发射波长的条件下,进行各样品的荧光测量,做三次平行试验。记录各浓度梯度目标菌的样品荧光强度,分析荧光型适体传感器检测大肠杆菌O157:H7污染牛乳样品的灵敏度。
荧光型适体传感器的灵敏性检验结果如图7所示。在大肠杆菌O157:H7纯培养中,测得荧光型适体传感器在大肠杆菌O157:H7浓度为104-107cfu/mL时具有良好的线性关系,随着大肠杆菌O157:H7浓度的增加,荧光强度随之增加,检出限为7.15×103cfu/mL(S/N=3)。在大肠杆菌O157:H7污染实际牛乳样品中,在预孵育1h后,测得荧光型适体传感器在大肠杆菌O157:H7浓度为103-106cfu/mL时具有良好的线性关系,随着大肠杆菌O157:H7浓度的增加,荧光强度随之增加,检出限为3.15×102cfu/mL(S/N=3)。因此,荧光型适体传感器对大肠杆菌O157:H7体现出较高的灵敏性。
3、荧光型适体传感器的重现性分析
分别随机选取8组相同和不同制备批次的试验体系,进行荧光型适体传感器的重现性评价,以分析组内和组间的试验差异。将相同浓度的大肠杆菌O157:H7纯培养物和各试验组的荧光适体传感体系,以10:1的体积比例,加入到避光的棕色离心管中。在涡旋振荡器下充分混合后,置于37℃培养箱中孵育10min。然后,将棕色离心管放在磁铁架上,使多壁碳纳米管复合物聚集分离,取溶液于黑色的96孔板中,在酶标仪下测量荧光信号强度,选用的样品激发波长是492nm,发射波长是532nm。记录测定各样品的荧光强度,做三次平行试验,作图分析,并计算组内和组间的相对标准偏差。
重现性是微生物检测技术评价的一个重要因素。分别选取8次组内和组间的试验样本,分析结果如图8所示,组内样本测量值较为聚集,组间样本测量值较为发散,表明组内样本比组间样本的重现性更好。进一步计算相对标准偏差,组内样本为3.57%,而组间样本为4.43%,两者均小于5%,表明组内和组间试验样本都存在比较好的重现性。
4、荧光型适体传感器的实用性评价
为进一步评价荧光型适体传感器检测大肠杆菌O157:H7的性能,随机选取市场上30份液态牛乳作为试验样品,按照国标GB4789.36-2016检测无大肠杆菌O157:H7后,以104cfu/mL的浓度,污染其中20份试验样品作为阳性组,其余10份试验样品作为阴性组,同时放在摇床孵育后,按照国际GB 4789.18-2010对所有液态乳样进行处理,随后采用2.2.6.2中实际样品检测的方法,完成对大肠杆菌O157:H7的测定。
将30份液态乳样做为试验样本,对荧光型适体传感器进行实用性评价。其中,在人工污染大肠杆菌O157:H7的20份阳性液态乳样中都可以检测到目标菌,而在没有人工污染大肠杆菌O157:H7的10份阴性液态乳样中都检测不到目标菌。表明本试验的荧光型适体传感器具有很好的实用性,检测达标率为100%。
以上所述仅为本申请的优选实施例而已,并不用于限制本申请,对于本领域的技术人员来说,本申请可以有各种更改和变化。凡在本申请的精神和原则之内,所作的任何修改、等同替换、改进等,均应包含在本申请的保护范围之内。

Claims (9)

1.一种多壁碳纳米管复合物的制备方法,其特征在于,所述多壁碳纳米管复合物主要是由多壁碳纳米管和羰基铁粉制成;所述多壁碳纳米管和羰基铁粉的比例为1:(1-6);
所述制备方法包括以下步骤:
(1)将多壁碳纳米管加入到缓冲液中,混匀,然后加入EDC和NHS,反应;
(2)步骤(1)反应结束后,加入羰基铁粉,混匀后,继续反应,即得;
所述多壁碳纳米管复合物在快速检测大肠杆菌中的应用;
所述多壁碳纳米管选自羧基化多壁碳纳米管。
2.根据权利要求1所述的多壁碳纳米管复合物的制备方法,其特征在于,所述多壁碳纳米管和羰基铁粉的比例为1:3。
3. 根据权利要求1所述的多壁碳纳米管复合物的制备方法,其特征在于,步骤(1)中,所述缓冲液为pH 4.0-6.0的缓冲液MES。
4. 根据权利要求1所述的多壁碳纳米管复合物的制备方法,其特征在于,步骤(1)中,所述缓冲液为pH 5.0的缓冲液MES。
5.根据权利要求1所述的多壁碳纳米管复合物的制备方法,其特征在于,步骤(1)中,所述反应的时间为110-130min;所述反应在25±2℃、160-200rpm的摇动中反应;步骤(2)中,所述反应的时间为20-70min;所述反应在25±2℃、160-200rpm的摇动中反应。
6.根据权利要求5所述的多壁碳纳米管复合物的制备方法,其特征在于,步骤(2)中,所述反应的时间为60min。
7.一种荧光型适体传感器,由权利要求1-6任一项所述制备方法中的多壁碳纳米管复合物制成。
8.权利要求7所述荧光型适体传感器的制备方法,其特征在于,包括以下步骤:
(1)取所述多壁碳纳米管复合物,加入去离子水,分散,然后与大肠杆菌适体混合;
(2)取上述混合物,超声分散50-70min后,4±2℃静置;
(3)磁选分离后,用去离子水洗涤3-5次,收集重悬后的溶液,即得。
9. 根据权利要求8所述的荧光型适体传感器的制备方法,其特征在于,所述大肠杆菌适体选自大肠杆菌O157:H7适体,其5’端修饰6-FAM基团,其核苷酸序列如SEQ ID NO.1所示;所述多壁碳纳米管复合物与大肠杆菌适体的比例为1:1。
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