Evanescent wave fibre optic sensor for detection of L. donovani specific antibodies in sera of kala azar patients.

An easy-to-use technique for detection of antibodies specific for the parasite L. donovani in human serum sample has been developed. The method is based on an evanescent wave generated from a tapered configuration of decladded optical fibre and does not require any volumetric measurement. Tapered fibres are immobilized with the purified cell surface protein of L. donovani by covalent bonding. Treated fibres are incubated with the patient serum for 10 min followed by incubation with goat anti human IgG tagged FITC. Fluorescent intensity from the fibre has been shown to be proportional to L. donovani specific antibodies present in the test sera. Direct readings can be obtained after signal enhancement through a photomultiplier tube within 5 min. The system, when tested on 12 positive sera, did not show any false negative result. Also, no false positive result was obtained with serum samples of patients infected with leprosy, tuberculosis, typhoid and malaria, showing the specificity of the sensor and efficacy of the technique.

[1]  T. Glass,et al.  Instrumentation for Cylindrical Waveguide Evanescent Fluorosensors , 1991 .

[2]  W. Little,et al.  A new immunoassay based on fluorescence excitation by internal reflection spectroscopy. , 1975, Journal of immunological methods.

[3]  M. T. Flanagan,et al.  Metal phosphate planar waveguides for biosensors. , 1994, Applied optics.

[4]  Frances S. Ligler,et al.  A fiber optic biosensor: combination tapered fibers designed for improved signal acquisition , 1993 .

[5]  David L. Kaplan,et al.  Tapered fiber tips for fiber optic biosensors , 1995 .

[6]  Frances S. Ligler,et al.  Chemistry and Technology of Evanescent Wave Biosensors , 1991 .

[7]  Rudolf E. Slovacek,et al.  Evanescent Wave Immunosensors for Clinical Diagnostics , 1991 .

[8]  N. F. Starodub,et al.  Construction and biomedical application of immunosensors based on fiber optics and enhanced chemiluminescence , 1994 .

[9]  H. Towbin,et al.  Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[10]  A. Helenius,et al.  The binding of detergents to lipophilic and hydrophilic proteins. , 1972, The Journal of biological chemistry.

[11]  J. Brown,et al.  Detection of Clostridium botulinum toxin A using a fiber optic-based biosensor. , 1992, Analytical biochemistry.

[12]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[13]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[14]  R. Parry,et al.  Detection of rubella antibody using an optical immunosensor. , 1990, Journal of virological methods.

[15]  J. Greve,et al.  The critical sensor: a new type of evanescent wave immunosensor. , 1996, Biosensors & bioelectronics.

[16]  R. Luginbühl,et al.  Immunosensing with photo-immobilized immunoreagents on planar optical wave guides. , 1995, Biosensors & bioelectronics.

[17]  J M Calvert,et al.  Use of thiol-terminal silanes and heterobifunctional crosslinkers for immobilization of antibodies on silica surfaces. , 1989, Analytical biochemistry.