Intel ISEF 2013 Finalist Profile

ME088 (Wu)
Colorimetric Detection of Plasmodium falciparum via Aptasensor Technology
Junyi (Sarah) Wu
Assumption College School, Brantford, CANADA

Where sophisticated diagnostic methods for malaria are not readily accessible, the disease is often confirmed based on symptoms such as high fever. This can result in misdiagnosis, and subsequently increased drug resistance. Although rapid diagnostic tests have been recommended, these antibody-based assays are limited by their high cost and instability. The goal was to develop a novel, cost-effective diagnostic method for the most common and dangerous strain of malaria, Plasmodium falciparum, through the simple and sensitive detection of the Plasmodium falciparum Histidine Rich Protein II (PfHRP2) using aptamer-gold nanoparticle conjugates. It was predicted that in the presence of PfHRP2, PfHRP2 specific aptamer-gold nanoparticles would bind to the protein, forming red dots due to the unique optical properties of gold. The sensitivity was improved with a silver enhancement solution that amplified the gold nanoparticle label. The conjugation of thiolated oligonucleotides to gold nanoparticles was followed by UV-Vis spectroscopy characterization. The actual test involved four steps: 1) immobilization of the sample onto nitrocellulose membrane 2) incubation with blocking buffer 3) incubation with aptamer-gold nanoparticle conjugates 4) silver enhancement. The results demonstrate the ability of aptamer-gold nanoparticle conjugates to bind to PfHRP2, introducing the first aptasensor colorimetric detection method for Plasmodium falciparum. As aptamers emerge as a worthy alternative to antibodies, an aptamer-based test could become more effective and feasible than its antibody counterpart. The proposed method’s simplicity results in minimal equipment and required training, thus presenting a potential solution for widespread distribution in developing nations.

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