Portable and power-free serodiagnosis of Chagas disease using magnetic levitating microbeads

Abstract

This work describes the detection of anti-T. cruzi antibodies in whole blood solutions using magnetic levitating microbeads (MLμBs). This simple diagnostic method can be easily performed by minimally trained personnel using an inexpensive and portable magnetic stage that requires no electricity. A multiphase test tube containing the MLμBs facilitates the sequential incubation, filtering, and reading of the immunoassays. The diagnostic method starts by adding a blood sample to the top phase of the test tube where the anti-T. cruzi antibodies present in the blood attach to the T. cruzi antigens on the surface of the MLμBs. Shaking the test tube after incubation mixes the top layer with a paramagnetic medium loaded with SiO microcrystals. The attachment of SiO microcrystals to those MLμBs bound to T. cruzi antibodies decreases their levitation height once the tube is placed between two antialigned permanent magnets. Measuring the levitation height of MLμBs enables the accurate detection and quantification of anti-T. cruzi antibodies in the blood across the clinically relevant range, with a detection limit of 5 μg mL. The small size of the test tubes facilitates the simultaneous analysis of over 50 different samples. MLμBs act as partial collimators for non-polarized light, facilitating their visual identification by the naked eye or by projecting incident light on a thin paper screen. A machine-vision algorithm was created to automatically interpret the results of the MLμB tests from a digital image, resulting in a rapid, accurate, and user-friendly assay for Chagas disease that can be used in resource-limited settings.

Magnetic Levitation in Chemistry, Materials Science, and Biochemistry

“…[7,87] TheM artinez group has prototyped aserological assay for diagnosing disease in resource-limited settings. [88] Yu has applied Maglev to analyze cooking oils. [89] Grzybowski has developed potentially important methods to carry out magnetic tweezing and self-assembly of diamagnetic colloids in paramagnetic solutions.…”

“…[89] Grzybowski has developed potentially important methods to carry out magnetic tweezing and self-assembly of diamagnetic colloids in paramagnetic solutions. [90][91][92] Thew ork of these groups is summarized in their papers and in separate reviews; [6,7,69,72,76,[87][88][89]92] their work, and these summaries and analyses,a re described and referenced in appropriate sections of this Review.…”

“…•C haracterization of kinetics of free-radical polymerization of low-molecular-weight monomers [111] •M onitoring of chemical reactions supported on asolid substrate (e.g. ap olymericb ead) [42,123] •C arrying out density-linked assays for biological molecules (e.g.,p roteins) [88,[106][107][108] 4.1. Density Measurement of Materials 4.1.…”

Magnetische Levitation in Chemie, Materialwissenschaft und Biochemie

“…haben einen innovativen Ansatz entwickelt, der MagLev und Zentrifugation zur dynamischen Kontrolle der dichtebasierten Analyse integriert [7, 87] . Die Martinez‐Gruppe hat einen serologischen Assay zur Diagnose von Krankheiten bei begrenzten Ressourcen entwickelt [88] . Yu hat Maglev eingesetzt, um Speiseöle zu analysieren [89] .…”

“…Grzybowski hat potenziell wichtige Methoden entwickelt, um magnetische Pinzetten und die Selbstorganisation von diamagnetischen Kolloiden in paramagnetischen Lösungen durchzuführen [90–92] . Die Arbeit dieser Gruppen ist in ihren Veröffentlichungen und in separaten Übersichtsartikeln zusammengefasst; [6, 7, 69, 72, 76, 87–89, 92] ihre Arbeit, dessen Zusammenfassungen und Analysen werden in entsprechenden Abschnitten dieses Aufsatzes beschrieben und referenziert.…”