Analytical and Bioanalytical Chemistry

, Volume 382, Issue 7, pp 1491–1499 | Cite as

Enzyme-catalyzed amplified immunoassay for the detection of Toxoplasma gondii-specific IgG using Faradaic impedance spectroscopy, CV and QCM

Original Paper

Abstract

A highly sensitive electrochemical immunoassay for Toxoplasma gondii-specific IgG (Tg-IgG) in human serum has been developed that is based on an enzyme-catalyzed amplification due to the formation of an insoluble precipitate on the surface of a quartz crystal microbalance (QCM). T. gondii antigen (TgAg) was immobilized on the surface of a gold electrode in order to bind Tg-IgG, and this was followed by the addition of anti-Tg-IgG horseradish peroxidase conjugate (anti-Tg-IgG-HRP). Subsequent exposure to 3,3′-diaminobenzidine (DAB) led to the enzymatically-catalyzed amplified deposition of the oxidation products on the QCM surface in the presence of H2O2. The transduction methods electrochemical Faradaic impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to assay the resistance to electron transfer at the conductive support upon accumulation of the insoluble products. The precipitation process was monitored in real time by QCM. The assay conditions, including the concentration of immobilized TgAg and the dosage of anti-Tg-IgG-HRP conjugate, were optimized. It was found that the amount of precipitate that accumulated on the conductive QCM surface was determined by the concentration of the target analyte Tg-IgG and the time permitted for biocatalyzed precipitation. The technique was shown to give a linear electron transfer resistance response (as measured by EIS) for Tg-IgG dilutions ranging between 1:8000 and 1:200, and a detection limit of 1:9600 dilution.

Keywords

Toxoplasma gondii-specific IgG Amplification strategy Faradaic impedance spectroscopy Cyclic voltammetry Quartz crystal microbalance 

References

  1. 1.
    Ahn HJ, Kim S, Nam HW (2003) Korean J Parasitol 41:89–96PubMedGoogle Scholar
  2. 2.
    Araujo FG, Remington JS (1987) Eur J Chin Microbiol 6:1–12Google Scholar
  3. 3.
    Doherty TM, Chougnet C, Schit M, Patterson B, Fox C, Shearer GM, Englund G, Sher A (1999) J Immunol 163:1506–1515PubMedGoogle Scholar
  4. 4.
    Li YH, Liu SX, Song CC, Yu SH (1991) Immunology of verminosis and immunological diagnosis. Science and Technology Press, Jiangsu, ChinaGoogle Scholar
  5. 5.
    Aubert D, Maine GT, Villena I, Hunt JC, Howard L, Shen M, Borjanac S, Chovan LE, Pin JM (2000) J Clin Microbiol 38:1144–1150PubMedGoogle Scholar
  6. 6.
    Clerio A, Del R.S, Giannessi D, (2000) Clin Chem 46:1529–1534PubMedGoogle Scholar
  7. 7.
    Ebersole RC, Ward MD (1988) J Am Chem Soc 110:8623–8628CrossRefGoogle Scholar
  8. 8.
    Pei RJ, Cheng ZL, Wang EK, Yang XR (2001) Biosens Bioelectron 16:355–361CrossRefPubMedGoogle Scholar
  9. 9.
    Bardea A, Katz E, Willner I (2000) Electroanalysis 12:1097–1106CrossRefGoogle Scholar
  10. 10.
    Patolsky F, Katz E, Bardea A, Willner I (1999) Langmuir 15:3703–3706CrossRefGoogle Scholar
  11. 11.
    Liu Y, Che Y, Li Y (2001) Sens Actuators B 72:214–218CrossRefGoogle Scholar
  12. 12.
    Charles PT, Kusterbeck AW (1999) Biosens Bioelectron 14:387–396CrossRefPubMedGoogle Scholar
  13. 13.
    Dodeigne C, Thunus L, Lejeune R (2000) Talanta 51:415–439CrossRefGoogle Scholar
  14. 14.
    Alfonate L, Willnar I (2001) Anal Chem 73:5287–5295CrossRefPubMedGoogle Scholar
  15. 15.
    Liu CH, Liao KT, Huang HJ (2000) Anal Chem 72:2925–2929CrossRefPubMedGoogle Scholar
  16. 16.
    Dai Z, Yan F, Chen J, Ju H.X (2003) Anal Chem 75:5429–5434CrossRefPubMedGoogle Scholar
  17. 17.
    Alfonate L, Katz E, Willner I (2000) Anal Chem 72:927–935CrossRefPubMedGoogle Scholar
  18. 18.
    Ruan CM, Yang LJ, Li YB (2002) Anal Chem 74:4814–4820CrossRefPubMedGoogle Scholar
  19. 19.
    Katz E, Alfonate L, Willner I (2001) Sens Actuators B 76:134–141CrossRefGoogle Scholar
  20. 20.
    Reddy SM, Jones JP, Lewis TJ, Vadama PM (1998) Anal Chim Acta 363:203–213CrossRefGoogle Scholar
  21. 21.
    Stoynov ZB, Grafov BM, Savova-Stoynoa BS, Elkin VV (1991) Electrochemical impedance. Nauka, MosowGoogle Scholar
  22. 22.
    Buttry DA, Ward MD (1992) Chem Rev 92:1355–1379CrossRefGoogle Scholar
  23. 23.
    Roederer JE, Bastiaans GJ (1983) Anal Chem 55:2333–2336CrossRefGoogle Scholar
  24. 24.
    Wang H, Li JS, Ding YJ et al (2004) Anal Chim Acta 501:37–43Google Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082P. R. China

Personalised recommendations