DNA aptamer targeting Plasmodium falciparum histidine rich protein 2: Development of aptamer—antibody sandwich assay for malaria rapid diagnosis

Abstract

Introduction: Aptamers are single-stranded oligonucleotides that specifically bind to their targets, which providing a remarkable potential application for improving malaria diagnosis. Histidine rich protein 2 (HRP2) is a diagnostic marker for malaria that produced by Plasmodium falciparum. Herein, a novel aptamer-antibody hybrid sandwich assay that targeting HRP2 is developed for the diagnosis of malaria. Method: HRP2 specific aptamer was identified by using Systematic Evolution of Ligands by EXponential enrichment (SELEX). Identified HRP2 aptamer was immobilised to microtitre plate for capturing HRP2, presences of HRP2 was detected by horseradish peroxidase conjugated antihistidine antibody, and signal was developed by adding 3,3',5,5'-tetramethylbenzidine. Limit of detection (LoD) and specificity was evaluated by using recombinant HRP2 and human whole blood samples spiked with malaria parasite cultures. Results: LoD of the aptamer-antibody hybrid assay is 0.9 μg/mL of recombinant HRP2. And, this assay is able to detect different percentages of malaria parasite in human whole blood and able to distinguish the samples with and without parasites. Conclusion: The present study identified an aptamer that able to recognise HRP2 from the parasite culture, which has a great potential application on different detection approaches. This work lays a foundation for further development of malaria diagnosis by using aptamer technology.