30th January 2019

Malaria is a serious life-threatening disease, affecting a large section of the population mostly in tropical and subtropical low and middle income countries (Gallup and Sachs, 2001; World Malaria Report,2016). Currently, lateral flow based immuno-chromatographic tests are widely used for detection of malaria. However, these antibody based assays are usually non-quantitative in nature and their stability is impaired in hot and humid environment (Ranadive et al., 2017). The focus of the current work is to explore a detection platform for the malaria biomarker Plasmodium falciparum glutamate dehydrogenase (PfGDH) in serum samples , amenable for integration into a portable device that complies well with the ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment free and Deliverable to end-users) mandate of WHO for application in developing and underdeveloped countries (Kunte and Kunwar, 2011).

A 90 mer long ssDNA aptamer selective to PfGDH was developed and used to capture the target protein using an extended gate field effect transistor (egFET). The intrinsic surface net charge of the captured protein led to change in gate potential of the device, which could be correlated to the concentration of the protein. This biosensor offered response time in seconds (~5 s), detection limit down to picomolar level (48.6 pM), and detection range in lower concentration region (0.1 pM to 10,000 pM) in diluted serum samples.  The high selectivity of the biosensor for PfGDH was verified by testing relevant analogous human and parasitic proteins on the device. Overall, the results validated the application potential of the developed aptaFET for diagnosis of both symptomatic and asymptomatic malaria.

Singh, N., Thungon, P., Estrela, P. and Goswami, P. (2019). Development of an aptamer-based field effect transistor biosensor for quantitative detection of Plasmodium falciparum glutamate dehydrogenase in serum samples. Biosensors and Bioelectronics, 123, pp.30-35.

https://www.sciencedirect.com/science/article/pii/S0956566318307826?via%3Dihub

Aptamer Group is currently developing aptamers to a variety of protein, cell, and peptide targets for biosensor development, if you would like more information on aptamers for diagnostics contact us using the form below.

References:

Gallup, J.L.,  Sachs, J.D. (2001) The economic burden of malaria (Conference Paper). American Journal of Tropical Medicine and Hygiene, Volume 64, Issue 1-2 SUPPL., 2001, Pages 85-96.

World Health Organization (2016) World Malaria Report 2016. http://www.who.int/malaria/publications/world-malaria-report-2016/report/en/

Ranadive, N., Kunene,S. Darteh, S., Ntshalintshali, N., Nhlabathi, N.,  Dlamini, N., Chitundu, S., Saini, M., Murphy, M., Soble, A., Schwartz, A., Greenhouse, B., Hsiang, M.S. (2017) Limitations of rapid diagnostic testing in patients with suspected malaria: A diagnostic accuracy evaluation from Swaziland, a low-endemicity country aiming for malaria elimination. Clinical Infectious Diseases Volume 64, Issue 9, 2017, Pages 1221-1227.

Kunte, R., Kunwar, R. (2010) WHO Guidelines for the treatment of malaria, second edition, WHO Press, World Health Organization, 20 Avenue appia, CH-1211 Geneva 27, Switzerland (2010), p. 194.

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