Analytical and Bioanalytical Chemistry

, Volume 406, Issue 22, pp 5369–5378 | Cite as

Preparation of QP4VP-b-LCP liquid crystal block copolymer and its application as a biosensor

  • Muhammad Omer
  • Soo-Young ParkEmail author
Research Paper


The interface between nematic liquid crystal, 4-cyano-4′-pentylbiphenyl (5CB), and water in a transmission electron microscopy (TEM) grid cell coated with QP4VP-b-LCP (quaternized poly(4-vinylpyridine) (QP4VP) and poly(4-cyanobiphenyl-4′-oxyundecylacrylate) (LCP)) was examined for protein and DNA detection. QP4VP-b-LCP was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Quaternization of P4VP with iodomethane (CH3I) made it a strong cationic polyelectrolyte and allowed QP4VP-b-LCP to form complexes with oppositely charged biological species. Several proteins, such as bovine serum albumin (BSA), hemoglobin (Hb), α chymotrypsinogen-A (ChTg), and lysozyme (LYZ), were tested for nonspecific protein detection. By injecting the protein solutions into the TEM grid cell, the initial homeotropic orientation of the TEM grid cell changed to a planar orientation above their isoelectric points (PIs) due to electrostatic interactions between QP4VP (+charge) and proteins (−charge), which did not occur below the PIs of the tested proteins. Their minimum concentrations at which the homeotropic to planar configurational change (H-P change) occurred were 0.01, 0.02, 0.03, and 0.04 wt.% for BSA, ChTg, Hb, and LYZ, respectively. One of the strong anionic polyelectrolytes, deoxyribonucleic acid (DNA) (due to the phosphate deoxyribose backbone) was also tested. A H-P change was observed with as little as 0.0013 wt.% salmon sperm DNA regardless of the pH of the cell. A H-P change occurred in 5CB and was observed by polarized optical microscopy. This simple and inexpensive setup for nonspecific biomaterial detection provides the basic idea for developing effective selective biosensors by introducing specific binding groups, such as the aptamer and antibody.


Strong cationic polyelectrolyte QP4VP-b-LCP Protein DNA RAFT polymerization Biosensor 



This work was supported by the National Research Foundation of Korea (NRF-2011-0020264).

Supplementary material

216_2014_7900_MOESM1_ESM.pdf (265 kb)
ESM 1 (PDF 264 kb)


  1. 1.
    Hamley IW, Castelletto V (2004) Small-angle scattering of block copolymers in the melt, solution and crystal states. Prog Polym Sci 29:909–948Google Scholar
  2. 2.
    Yeh SW, Wei KH, Sun YS, Jeng US, Liang KS (2005) CdS nanoparticles induce a morphological transformation of poly(styrene-b-4-vinylpyridine) from hexagonally packed cylinders to a lamellar structure. Macromolecules 38:6559–6565CrossRefGoogle Scholar
  3. 3.
    Seong HC, Chang HS, Kwang PL (2005) Preparation for protein separation of an ion-exchange polymeric stationary phase presenting amino acid and amine units through surface graft polymerization. Macromol Res 13:39–44CrossRefGoogle Scholar
  4. 4.
    Kyung WK, Hyun C, Gil SL, Dong JA, Min-K O (2006) Micro-patterned polydiacetylene vesicle chips for detecting protein-protein interactions. Macromol Res 14:483–485CrossRefGoogle Scholar
  5. 5.
    Sehoon J, Ui SK, Wonjin J, Chee BS (2009) Fabrication of multicomponent protein microarrays with microfluidic devices of poly(dimethylsiloxane). Macromol Res 17(No. 3):192–196CrossRefGoogle Scholar
  6. 6.
    Lee E, Kim J, Myung J, Youngjong K (2012) Modification of block copolymerphotonic gels for colorimetric biosensors. Macromol Res 20(No. 12):1219–1222CrossRefGoogle Scholar
  7. 7.
    Brake JM, Daschner MK, Luk YY, Abbott NL (2003) Biomolecular interactions at phospholipid-decorated surfaces of liquid crystals. Science 302:2094–2097CrossRefGoogle Scholar
  8. 8.
    Skaife JJ, Abbott NL (2001) Influence of molecular-level interactions on the orientations of liquid crystals supported on nanostructured surfaces presenting specifically bound proteins. Langmuir 17:5595–5604CrossRefGoogle Scholar
  9. 9.
    Skaife JJ, Brake JM, Abbott NL (2001) Influence of nanometer-scale topography of surfaces on the orientational response of liquid crystals to proteins specifically bound to surface-immobilized receptors. Langmuir 17:5448–5457CrossRefGoogle Scholar
  10. 10.
    Jerome B (1991) Surface effects and anchoring in liquid crystals. Rep Prog Phys 54:391–451CrossRefGoogle Scholar
  11. 11.
    York AW, Kirkland SE, McCormick CL (2008) Advances in the synthesis of amphiphilic block copolymers via RAFT polymerization: stimuli-responsive drug and gene delivery. Adv Drug Deliv Rev 60:1018–1036CrossRefGoogle Scholar
  12. 12.
    Lee DY, Seo JM, Khan W, Kornfield JA, Kurji Z, Park SY (2010) pH-responsive aqueous/LC interfaces using SGLCP-b-polyacrylic acid block copolymers. Soft Matter 6:1964–1970CrossRefGoogle Scholar
  13. 13.
    Khan W, Park SY (2012) Configuration change of liquid crystal microdroplets coated with a novel polyacrylic acid block liquid crystalline polymer by protein adsorption. Lab Chip 12:4553–4559CrossRefGoogle Scholar
  14. 14.
    Perrier S, Takolpuckdee P, Westwood J, Lewis DM (2004) Versatile chain transfer agents for reversible addition fragmentation chain transfer (RAFT) polymerization to synthesize functional polymeric architectures. Macromolecules 37:2709–2717CrossRefGoogle Scholar
  15. 15.
    Khan W, Seo JM, Park SY (2011) Synthesis and micellization of a novel diblock copolymer of poly(N-isopropylacrylamide)-b-SGLCP and its application in stability of 5CB droplets in aqueous medium. Soft Matter 7:11549CrossRefGoogle Scholar
  16. 16.
    Dubois JC, Decobert G, Barny PL, Friedrich SC, Noel C (1986) Liquid crystalline side chain polymers derived from poly-acrylate, poly-methyacrylate and poly-α-chloroacrylate. Mol Cryst Liq Cryst 137:349–364CrossRefGoogle Scholar
  17. 17.
    Bozovic-Vukic J, Manon HT, Meuldijk J, Koning C, Klumperman B (2007) SAN-b-P4VP block copolymer synthesis by chain extension from RAFT-functional poly(4-vinylpyridine) in solution and in emulsion. Macromolecules 40:7132–7139CrossRefGoogle Scholar
  18. 18.
    Yang JY, Mathauer Frank CW (1994) Microchemistry: spectroscopy and chemistry in small domains. In: Tamai N (ed) Masuhara H, FC Kitamura. North Holland, New YorkGoogle Scholar
  19. 19.
    Bicak N, Gazi M (2003) Quantitative quaternization of poly(4-vinyl pyridine). J Macromol Sci-Pure Appl Chem A40:585–591CrossRefGoogle Scholar
  20. 20.
    Sonmez HB, Bicak N (2002) Quaternization of poly(4-vinyl pyridine) beads with 2-chloroacetamide for selective mercury extraction. React Funct Polym 51:55–60CrossRefGoogle Scholar
  21. 21.
    Seo JM, Khan W, Park SY (2012) Protein detection using aqueous/LC interfaces decorated with a novel polyacrylic acid block liquid crystalline polymer. Soft Matter 8:198–203CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of Polymer ScienceKyungpook National UniversityDaeguSouth Korea

Personalised recommendations