Title

Characterization and utility of immobilized metal affinity-functionalized cellulose membranes for point-of-care malaria diagnostics

Document Type

Article

Publication Title

Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

Publication Date

12-1-2021

Abstract

Immobilized metal affinity chromatography (IMAC) is a well-established technique for protein separation and purification. IMAC has been previously utilized to capture the malaria biomarker histidine-rich protein 2 (HRP2) from blood, enhancing the sensitivity of field-appropriate diagnostic tools such as lateral flow assays. However, little work has been done to translate this technique to a truly field-usable design. In this study, IMAC-functionalized cellulose membranes are created and characterized fully for future use in applied malaria diagnostics. IMAC-functionalized cellulose membranes were investigated across a range of cellulose substrates, IMAC ligands, and divalent transition metals before use in a capture and elution flowthrough workflow. Following characterization and optimization, it was found that iminodiacetic acid bound to Zn(II) was the most promising ligand–metal pair, with three available coordination sites and a molar loading capacity of 57.7 μmol of metal/cm3 of cellulose. Using these parameters, more than 99% of HRP2 was captured from a large-volume lysed blood sample in a simple flow-through assay and 89% of the captured protein was eluted from the membrane using the chelating compound ethylenediaminetetraacetic acid. Use of this enhancement protocol on an in-house HRP2 lateral flow assay (LFA) yielded a limit of detection of 7 parasites/μL, a 15.8x enhancement factor compared to traditional LFA methods.

Volume

1186

DOI

10.1016/j.jchromb.2021.123023

ISSN

15700232

E-ISSN

1873376X

PubMed ID

34788723

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