Detecting circulating antibodies by controlled surface modification with specific target proteins: Application to malaria.

Cardoso, Ana R; Cabral-Miranda, Gustavo; Reyes-Sandoval, Arturo; Bachmann, Martin; Sales, M Goreti F (2017). Detecting circulating antibodies by controlled surface modification with specific target proteins: Application to malaria. Biosensors & bioelectronics, 91, pp. 833-841. Elsevier 10.1016/j.bios.2017.01.031

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Sensitive detection of specific antibodies by biosensors has become of major importance for monitoring and controlling epidemics. Here we report a development of a biosensor able to specifically measure antibodies in a drop of unmodified blood serum. Within minutes, the detection system measures presence of antibodies against Plasmodium vivax, a causing agent for malaria. The biosensor consists of a layer of carbon nanotubes (CNTs) which were casted on a carbon working electrode area of a three-electrode system and oxidized. An amine layer was produced next by modifying the surface with EDAC/NHS followed by reaction with a diamine compound. Finally, the protein fragments derived from P. vivax containing well-known antigen sequences were casted on this layer and bound through electrostatic interactions, involving hydrogen and ionic bonding. All these chemical changes occurring at the carbon surface along the biosensor assembly were followed and confirmed by Fourier Transformed Infrared s pectrometry (FTIR) and Raman spectroscopy. The presence of antibodies in serum was detected by monitoring the electrical properties of the layer, making use of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV), against a standard iron probe. Overall, the charge-transfer resistance decreased after antibody binding, because there was an additional amount of protein bound to the surface. This hindered the access of the iron redox probe to the conductive support at the electrode surface. Electrical changes could be measured at antibody concentration as low as ~6-50pg/L (concentrations in the range of 10-15M) and as high as ~70μg/L. Specific measurement with low background was even possible in undiluted serum. Hence, this novel biosensor allows assessing serum antibody levels in real time and in un-manipulated serum samples on-site where needed.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Dermatology, Urology, Rheumatology, Nephrology, Osteoporosis (DURN) > Clinic of Rheumatology, Clinical Immunology and Allergology

UniBE Contributor:

Bachmann, Martin

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0956-5663

Publisher:

Elsevier

Language:

English

Submitter:

Eveline Messerli

Date Deposited:

19 Mar 2018 14:24

Last Modified:

24 Oct 2019 13:06

Publisher DOI:

10.1016/j.bios.2017.01.031

PubMed ID:

28157657

Uncontrolled Keywords:

Antibodies Biosensor Electrochemical measurements Immune response detection Malaria

BORIS DOI:

10.7892/boris.110615

URI:

https://boris.unibe.ch/id/eprint/110615

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