A portable microfluidic Aptamer-Tethered Enzyme Capture (APTEC) biosensor for malaria diagnosis

• Published in: Biosensors & bioelectronics Vol. 100; pp. 591 - 596
• Main Authors: Fraser, Lewis A., Kinghorn, Andrew B., Dirkzwager, Roderick M., Liang, Shaolin, Cheung, Yee-Wai, Lim, Bryce, Shiu, Simon Chi-Chin, Tang, Marco S.L., Andrew, Dean, Manitta, Joseph, Richards, Jack S., Tanner, Julian A.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.02.2018
• Subjects: 3D print; Aptamer; Aptamers, Nucleotide - chemistry; biomarkers; Biosensing Techniques - instrumentation; biosensors; colorimetry; Colorimetry - instrumentation; Diagnosis; DNA; Humans; L-Lactate Dehydrogenase - isolation & purification; lactate dehydrogenase; Limit of Detection; magnetism; Malaria; Malaria - blood; Malaria - diagnosis; microbeads; Microfluidic; Microfluidic Analytical Techniques - instrumentation; Models, Molecular; oligonucleotides; parasites; patients; Plasmodium falciparum; Plasmodium falciparum - enzymology; Plasmodium falciparum - isolation & purification; point-of-care systems; Printing, Three-Dimensional; prototypes; 3D print; Plasmodium falciparum; Aptamer; Diagnosis; Malaria; Microfluidic
• DOI: 10.1016/j.bios.2017.10.001
• ISSN: 0956-5663; 1873-4235

There is a critical need for better biosensors for the detection and diagnosis of malaria. We previously developed a DNA aptamer that recognises the Plasmodium falciparum lactate dehydrogenase (PfLDH) enzyme with high sensitivity and specificity. The aptamer was integrated into an Aptamer-Tethered Enzyme Capture (APTEC) assay as a laboratory-based diagnostic approach. However, a portable equipment-free point-of-care aptamer-mediated biosensor could have a significant impact on malaria diagnosis in endemic regions. Here, we present a new concept for a malaria biosensor whereby aptamers are coated onto magnetic microbeads for magnet-guided capture, wash and detection of the biomarker. A biosensor incorporating three separate microfluidic chambers was designed to enable such magnet-guided equipment-free colorimetric detection of PfLDH. A series of microfluidic biosensor prototypes were optimised to lower rates of inter-chamber diffusion, increase sensitivity, and provide a method for point-of-care sample testing. The biosensor showed high sensitivity and specificity when detecting PfLDH using both in vitro cultured parasite samples and using clinical samples from malaria patients. The high performance of the biosensor provides a proof-of-principle for a portable biosensor that could be adaptable for a variety of aptamer-mediated diagnostic scenarios. •An aptamer-mediated magnet-guided microfluidic biosensor is developed.•The biosensor can be visualized by eye without other equipment.•The biosensor is integrated into a mobile tele-medical setup.•The biosensor could detect Plasmodium falciparum infection in patient blood samples.