Biomarker-mediated disruption of coffee-ring formation as a low resource diagnostic indicator.

Abstract

The ring pattern resulting from the unique microfluidics in an evaporating coffee drop is a well-studied mass transport phenomenon generating interest in the research community mostly from a mechanistic perspective. In this report, we describe how biomarker-induced particle-particle assemblies, magnetic separation, and evaporation-driven ring formation can be combined for simple pathogen detection. In this assay design, the presence of biomarkers causes self-assembly of a magnetic nanoparticle and a fluorescently labeled micrometer-sized particle. A small spherical magnet under the center of the drop prevents these assemblies from migrating to the drop's edge while a nonreactive control particle flows to the edge forming a ring pattern. Thus the presence or absence of biomarker results in distinctly different distributions of particles in the dried drop. Proof-of-principle studies using poly-L-histidine, a peptide mimic of the malaria biomarker pfHRPII, show that the predicted particle distributions occur with a limit of detection of approximately 200-300 nM.

• Authors: Joshua R Trantum, David W Wright, Frederick R Haselton
• Journal: Langmuir : the ACS journal of surfaces and colloids (Langmuir) Vol. 28 Issue 4 Pg. 2187-93 (Jan 31 2012) ISSN: 1520-5827 [Electronic] United States
• PMID: 22148855 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2011 American Chemical Society

Chemical References

• Antigens, Protozoan
• Biomarkers
• Fluorescent Dyes
• HRP-2 antigen, Plasmodium falciparum
• Protozoan Proteins
• polyhistidine
• Histidine

Topics

• Antigens, Protozoan (metabolism)
• Biomarkers (analysis, chemistry)
• Biomimetic Materials (chemistry, metabolism)
• Clinical Chemistry Tests (instrumentation)
• Fluorescent Dyes (chemistry)
• Histidine (chemistry, metabolism)
• Limit of Detection
• Magnets (chemistry)
• Malaria (diagnosis, metabolism)
• Microfluidic Analytical Techniques (instrumentation)
• Nanoparticles (chemistry)
• Protozoan Proteins (metabolism)
• Volatilization