Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (8): 664-668.DOI: 10.6023/A16040205 Previous Articles     Next Articles



刘兴奋a, 王亚腾a, 黄艳琴a, 冯晓苗a, 范曲立a, 黄维a,b   

  1. a 南京邮电大学信息材料与纳米技术研究院 有机电子与信息显示国家重点实验室培育基地 江苏省有机电子和信息显示协同创新中心 南京 210023;
    b 南京工业大学先进材料研究院 江苏省柔性电子重点实验室 先进生物与化学制造协同创新中心 南京 211816
  • 投稿日期:2016-04-25 发布日期:2016-08-10
  • 通讯作者: 刘兴奋
  • 基金资助:

    项目受国家重点基础研究发展计划项目(Nos. 2012CB933301,2012CB723402)、国家自然科学基金(Nos. 21005040、51173080)、“有机与生物光电子学”教育部创新团队(No. IRT1148)、江苏高校优势学科建设工程资助项目、江苏省自然科学基金(BK20141424)、江苏省普通高校研究生科研创新计划项目(CXLX12_0792)及南京邮电大学校科研项目(NY215171)资助.

Highly Sensitive Protein Biosensor based on a Conjugated Polymer Brush

Liu Xingfena, Wang Yatenga, Huang Yanqina, Feng Xiaomiaoa, Fan Qulia, Huang Weia,b   

  1. a Key Laboratory for Organic Electronics & Information Displays and Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China;
    b Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic InnovationCenter for Advanced Materials, Nanjing Tech University Nanjing Tech, Nanjing 211816, China
  • Received:2016-04-25 Published:2016-08-10
  • Supported by:

    Project supported by the National Basic Research Program of China (Nos. 2012CB933301, 2012CB723402), the National Natural Science Foundation of China (Nos. 21005040, 51173080), the Ministry of Education of China (No. IRT1148), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), the Natural Science Foundation of Jiangsu Province (BK20141424), Program of Scientific Innovation Research of College Graduate in Jiangsu Province (CXLX12_0792) and Research Program of Nanjing University of Posts and Telecommunications (NY215171).

Simple and sensitive detection of proteins is crucial in biological analysis and medical diagnosis. Conjugated polymers (CPs) with π-conjugated backbones were recognized as having excellent light-harvesting capability and high fluorescent quantum yield. They have been widely used as an energy donor to amplify fluorescence signal via high efficient Föster resonance energy transfer (FRET). In particular, conjugated polymer brush with high charge density provides more possibilities due to stronger electrostatic interactions with negatively charged biomolecules. Here, we developed a highly sensitive protein biosensor for thrombin detection based on a conjugated polymer brush (PFNI) and a fluorescein-labeled aptamer (FAM-apt15). PFNI is a water-soluble cationic polyfluorene derivate with extremely high charge density (78 positive charges per repeat unit). PFNI can attract negatively charged aptamer through strong electrostatic interactions. In this case, the energy donor (PFNI) and acceptor (FAM) are in a close proximity, which results in an efficient FRET process and a high FRET signal. However, when the FAM-apt15 combines with the target protein, a rigid and big-sized G-quadruplex/thrombin complex formed. Due to the steric hindrance from the densely brush of PFNI, the distance between the two fluorophores increased significantly, leading to an inefficient FRET process and a low FRET signal. The strategy exhibits excellent specificity and the limit of detection (LOD) for thrombin in buffer was estimated to be 0.05 nmol/L. It also works well in diluted serum and a LOD of 0.2 nmol/L can be obtained. Compared to the biosensors based on traditional linear conjugated polymers, the sensitivity was improved by one order of magnitude. In addition, our strategy also shows the merits of simple, label-free, and low-cost because labeled DNA is much more expensive than unlabeled one. Based on the specific binding of aptamer and protein, this novel method can be extended to a highly sensitive detection of more proteins.

Key words: conjugated polymer, aptamer, Föster resonance energy transfer, thrombin, biosensor