ORIENTED IMMOBILIZED ANTIBODIES IN SERS-BASED
IMMUNOASSAY AGAINST BOVINE LEUKEMIA VIRUS
Author: Julija Baniukevic, doctoral candidate of Nanotechnology Research Center,
Chemistry Faculty, Vilnius university, Lithuania
1st International Baku Forum
Outline
What are the immunosensors?
Research object
The ways to achieve the goal
Conclusions
Nanoprospectives
What are the immunosensors?
What are the immunosensors?
Ab + Ag ↔ AbAgSharma SK, Seghal N, Kumar A. Biomolecules for development of biosensors and their applications.
Current Applied Physics. 2003; 3: 307-316. Wang J. Analytical electrochemistry. 2nd ed. New York: Wiley-VCH: 2000; 52-54, 183-188
Antibodies and their structure
Bovine leukemia virus structure
Reverse transcriptase
gp51/gp30
RNA
p15
Integrase
Lipids layer
p24
Nermut MV, Hockley DJ. Comparative morphology and structural classification of retroviruses. Curr Top Microbiol Immunol 1996; 214: 1-22.
Antibody-antigen interaction
Karyakin AA, Presnova GV, Rubtsova MY, Egorov AM. Oriented immobilization of antibodies onto the gold surfaces via their native thiol groups. Anal Chem 2000; 72: 3805-3811
Immunosensor design
Immunosensors devices
Schematic illustration of SERS-based sandwich immunoassay for BLV gp51
detection
Capturing efficiency of antibody on MNP-Au and retained antigen binding
efficiency measured with HPLC.
SAM DTT-1 DTT-2 2-ME
Ca
ptu
ring
effic
ien
cy,%
0
20
40
60
80
100
120
140MNP-Au-Ab immobilization efficiencyMNP-Au-Ab-Ag binding efficiency
88,8 %92,7 % 95,3 %
11,4 %
59,2 %58,7 %
50,3 %
SERS spectra of A) BLV antigen gp51; B) Raman label and anti–gp51 labeled Au-NRs (TNB-labeled anti–gp51-Au-NRs) in
the sandwich immunoassay without antigen; C) Raman Raman label and anti–gp51 labeled Au-NRs (TNB-labeled anti–gp51-
Au-NRs) with 0.1 mg mL-1 of antigen in the sandwich immunoassay.
Raman shift, cm-1
SE
RS
in
ten
sit
y,
a.u
.
Why is it so important?
Bovine leukemia virus consequences
http://www.vetmed.ucdavis.edu/vetext/INF-DA/INF-DA_BovineLeukemia.html
Conclusions
The developed SERS-based immunoassay based on oriented immobilisation of antibodies on MNP-Au and magnetic separation after interaction with analyte presents an indirect, less time consuming and easy-to-use method for antigen detection.
A good linear correlation (R2=0.9983) between the SERS signal and antigen concentration was obtained within the range of 0-0.06 mg mL-
1 of gp51 concentration.
The sensitivity of the developed assay was investigated and the LOD and LOQ of the proposed method for gp51 detection were found to be 0.95 µg mL-1 and 3.14 µg mL-1, respectively.
Conclusions
This method was successfully applied for the detection of bovine leukemia virus antigen gp51 in a milk samples in a rapid, reliable and selective manner. Recoveries of the proposed method in real samples were in the range of 85.5 – 100 %.
It was found that better recovery was achieved by increasing the concentration of analyte. The proposed SERS-based immunoassay using MNP-Au can be applied for the detection of other analytes.
Enhancing public engagement with nanotechnology
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Thank you for your attention
Thank you for your attention