Direct transfer of HRPII-magnetic bead complexes to malaria rapid diagnostic tests significantly improves test sensitivity

Malaria Journal

Methodology

Nicholas M. Adams¹  Thomas F. Scherr¹  David W. Wright²  Keersten M. Ricks²  Frederick R. Haselton³ 

[1] Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA;Department of Chemistry, Vanderbilt University, 37235, Nashville, TN, USA;Department of Chemistry, Vanderbilt University, 37235, Nashville, TN, USA;Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA;

关键词: Malaria;    Diagnostics;    Extraction;    Magnetic beads;    Biomarker concentration;   

DOI  :  10.1186/s12936-016-1448-6

 received in 2016-04-15, accepted in 2016-07-20,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundThe characteristic ease of use, rapid time to result, and low cost of malaria rapid diagnostic tests (RDTs) promote their widespread use at the point-of-care for malaria detection and surveillance. However, in many settings, the success of malaria elimination campaigns depends on point-of-care diagnostics with greater sensitivity than currently available RDTs. To address this need, a sample preparation method was developed to deliver more biomarkers onto a malaria RDT by concentrating the biomarker from blood sample volumes that are too large to be directly applied to a lateral flow strip.MethodsIn this design, Ni–NTA-functionalized magnetic beads captured the Plasmodium falciparum biomarker HRPII from a P. falciparum D6 culture spiked blood sample. This transfer of magnetic beads to the RDT was facilitated by an inexpensive 3D-printed apparatus that aligned the sample tube with the sample deposition pad and a magnet beneath the RDT. Biomarkers were released from the bead surface onto the lateral flow strip using imidazole-spiked running buffer. Kinetics of HRPII binding to the Ni–NTA beads as a function of blood sample volume were explored prior to determining the effect of the proposed method on the limit of detection of Paracheck RDTs.ResultsMore than 80 % of HRPII biomarkers were extracted from blood sample volumes ranging from 25 to 250 µL. The time required to reach 80 % binding ranged from 5 to 60 min, depending on sample volume. Using 250 μL of blood and a 30-min biomarker binding time, the limit of detection of the Paracheck Pf RDT brand was improved by 21-fold, resulting in a limit of detection below 1 parasite/μL.ConclusionsThis approach has the sensitivity and simplicity required to assist in malaria elimination campaigns in settings with limited access to clinical and laboratory resources.

【 授权许可】

CC BY   
© The Author(s) 2016

【 图 表 】

Fig. 2