Electrochemical magneto-actuated biosensor for CD4 count in AIDS diagnosis and monitoring.
The counting of CD4(+) T lymphocytes is a clinical parameter used for AIDS diagnosis and follow-up. As this disease is particularly prevalent in developing countries, simple and affordable CD4 cell counting methods are urgently needed in resource-limited settings. This paper describes an electrochemical magneto-actuated biosensor for CD4 count in whole blood. The CD4(+) T lymphocytes were isolated, preconcentrated and labeled from 100 μL of whole blood by immunomagnetic separation with magnetic particles modified with antiCD3 antibodies. The captured cells were labeled with a biotinylated antiCD4 antibody, followed by the reaction with the electrochemical reporter streptavidin-peroxidase conjugate. The limit of detection for the CD4 counting magneto-actuated biosensor in whole blood was as low as 44 cells μL(-1) while the logistic range was found to be from 89 to 912 cells μL(-1), which spans the whole medical interest range for CD4 counts in AIDS patients. The electrochemical detection together with the immunomagnetic separation confers high sensitivity, resulting in a rapid, inexpensive, robust, user-friendly method for CD4 counting. This approach is a promising alternative for the costly standard flow cytometry and suitable as diagnostic tool at decentralized practitioner sites in low resource settings, especially in less developed countries.
Grup de Sensors i Biosensors, Departament de Química, Universitat Autònoma de Barcelona, Spain.
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Carinelli
Laboratory of Cellular Immunology, Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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Xufré Ballesteros
Laboratory of Cellular Immunology, Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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Martí
Grup de Sensors i Biosensors, Departament de Química, Universitat Autònoma de Barcelona, Spain.
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Alegret
Grup de Sensors i Biosensors, Departament de Química, Universitat Autònoma de Barcelona, Spain. Electronic address: Isabel.Pividori@uab.cat.
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Pividori
D000163:Acquired Immunodeficiency Syndrome / Q000097:blood* / Q000175:diagnosis; D015704:CD4 Antigens / Q000032:analysis / Q000097:blood / Q000276:immunology; D018791:CD4 Lymphocyte Count / Q000379:methods*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D015704:CD4 Antigens
AIDS; CD4 counting; CD4(+) T lymphocyte; Electrochemical biosensor; HIV; Immunomagnetic separation; Magnetic particle; Magneto-electrode