Journal of Nanoparticle Research

, Volume 13, Issue 6, pp 2407–2415

Improving colloidal properties of quantum dots with combined silica and polymer coatings for in vitro immuofluorenscence assay

  • Bingbo Zhang
  • Da Xing
  • Chao Lin
  • Fangfang Guo
  • Peng Zhao
  • Xuejun Wen
  • Zhihao Bao
  • Donglu Shi
Research Paper

DOI: 10.1007/s11051-010-0131-z

Cite this article as:
Zhang, B., Xing, D., Lin, C. et al. J Nanopart Res (2011) 13: 2407. doi:10.1007/s11051-010-0131-z

Abstract

Semiconductor quantum dots (QDs) are promising fluorescence probes for immuofluorescence assay in the biological applications. However, water solubilization and non-specific binding are two critical issues to be addressed for the practical uses. Here, we reported a new type of QDs with combined silica and polymer coating. QDs with excellent colloidal properties were prepared via carboxylation of the amino groups on the surface of silica-coated QDs by reacting with multi-carboxyl poly (acrylic acid) (PAA). Hydrodynamic size of PAA-functionalized silica-coated QDs was around 40 nm. They were highly fluorescent (about 47.8% quantum yield). No precipitate of QDs was observed after 3 month storage at 4 °C. When cancer cells (HeLa) were used, the functionalized QDs exhibited little or no non-specific cellular binding. The results from in vitro experiments indicated that PAA-functionalized silica-coated QDs-antibody bioconjugates had excellent antigen-capture ability and exhibited little or no non-specific binding to polystyrene spheres which were used to immobilize the antigen for immuoflurescence assay. The PAA-functionalized silica-coated QDs with improved colloidal properties could serve as excellent alternative fluorescent probes for biodetection.

Keywords

Quantum dots Colloidal properties Poly (acrylic acid) Silica Immunofluorescence assay Nanomedicine 

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Bingbo Zhang
    • 1
    • 2
  • Da Xing
    • 2
  • Chao Lin
    • 1
  • Fangfang Guo
    • 1
  • Peng Zhao
    • 1
  • Xuejun Wen
    • 3
  • Zhihao Bao
    • 1
  • Donglu Shi
    • 1
    • 4
  1. 1.The Institute for Advanced Materials and Nano BiomedicineTongji UniversityShanghaiChina
  2. 2.MOE Key Laboratory of Laser Life ScienceSouth China Normal UniversityGuangzhouChina
  3. 3.Clemson-MUSC Bioengineering Program, Department of BioengineeringClemson UniversityCharlestonUSA
  4. 4.School of Energy, Environmental, Biological and Medical EngineeringUniversity of CincinnatiCincinnatiUSA

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